p.32
Nervous System Control of GI Functions
What is the sensory homunculus?
A visual representation of the body as seen by the brain, highlighting areas of sensory information.
p.62
Esophageal Motility and Peristalsis
What is retroperistalsis?
Retroperistalsis is the reverse of peristalsis, where the contents of the stomach move back up into the esophagus.
p.26
Pathophysiology of GI Disorders
What relieves the patient's abdominal pain?
Taking antacids that contain bicarbonate.
p.26
Pathophysiology of GI Disorders
What did the endoscopy reveal in the patient?
An ulcer in the duodenum.
p.32
Nervous System Control of GI Functions
How does the sensory homunculus function as a defense mechanism?
It helps the brain prioritize sensory information, which can be crucial for survival and defense.
p.51
Nervous System Control of GI Functions
Do ganglia play a role in the motility of the esophagus?
No, ganglia do not play a role in the motility of the esophagus.
p.42
Pathophysiology of GI Disorders
What type of disorder is Sjogren's Syndrome?
Sjogren's Syndrome is an autoimmune disorder.
p.23
Nervous System Control of GI Functions
What is associated with muscular contraction?
The occurrence of action potentials.
p.5
Esophageal Motility and Peristalsis
What is achalasia?
Achalasia is a condition characterized by the absence of relaxation of the lower esophageal sphincter (LES) and impaired peristalsis in the distal esophagus.
p.5
Esophageal Motility and Peristalsis
What are the treatment options for achalasia?
Treatment options for achalasia include pneumatic dilation, Botox injections, medications such as nitroglycerin, and surgery.
p.26
Pathophysiology of GI Disorders
What symptoms did the 52-year-old man present with?
Abdominal pain, nausea, loss of appetite, frequent belching, and diarrhea (floaters).
p.59
Esophageal Motility and Peristalsis
What neurotransmitters are involved in the latency gradient in esophageal circular smooth muscle?
VIP (Vasoactive Intestinal Peptide) or NO (Nitric Oxide).
p.9
Nervous System Control of GI Functions
How does norepinephrine affect the gut in the context of the sympathetic division?
Norepinephrine acts on smooth muscle and/or neurons of the enteric nervous system to decrease motor and secretory activity.
p.59
Nervous System Control of GI Functions
What types of neurotransmitters are released from the Myenteric Plexus to control the Lower Esophageal Sphincter (LES)?
Both excitatory and inhibitory neurotransmitters.
p.23
Nervous System Control of GI Functions
In the context of electrical activity and mechanical action, what is more important: number or amplitude?
Number is more important than amplitude.
p.51
Nervous System Control of GI Functions
What is the function of the swallowing center in relation to the esophagus?
The swallowing center coordinates the process of swallowing, ensuring the proper movement of food from the mouth through the esophagus.
p.53
Esophageal Motility and Peristalsis
What is the role of the nucleus ambiguus in esophageal peristalsis?
The nucleus ambiguus is involved in controlling the peristalsis of the striated muscle portion of the esophagus.
p.41
Pathophysiology of GI Disorders
What complication can mumps cause in adult men?
Inflammation of the testes, which can affect fertility.
p.9
Nervous System Control of GI Functions
Where does the sympathetic division of the nervous system originate in the spinal cord?
The sympathetic division originates in the spinal cord segments T1 to L3.
p.74
Gastric Motility and Emptying
What is the appropriate response required to permit the exit of a swallowed quarter from a child's stomach?
The mixing and grinding movements in the stomach.
p.46
Functions of the GI Tract
What controls actin/myosin interaction in smooth muscle?
Calcium/calmodulin (Ca/CM).
p.61
Gastroesophageal Reflux Disease (GERD)
What symptoms did the 58-year-old man present with at the clinic?
Mild chronic cough and heartburn.
p.26
Pathophysiology of GI Disorders
What is the likely diagnosis for the patient given the symptoms and test results?
Zollinger-Ellison syndrome, characterized by a gastrin-secreting tumor (gastrinoma) leading to increased gastric acid production.
p.43
Nervous System Control of GI Functions
Which types of medications are known to have muscarinic antagonist properties that can cause dry mouth?
Allergy medications with H1 receptor antagonists (e.g., pyrilamine/mepyramine) and tricyclic antidepressants (e.g., imipramine).
p.43
Nervous System Control of GI Functions
What effect do agents that inhibit acetylcholine breakdown have on salivation?
Agents that inhibit acetylcholine breakdown induce salivation.
p.29
Nervous System Control of GI Functions
Which cranial nerves carry efferent output from the swallowing center?
The 5th (trigeminal), 10th (vagus), and 12th (hypoglossal) cranial nerves.
p.49
Esophageal Motility and Peristalsis
How does esophageal pressure at rest compare to intraabdominal pressure?
At rest, esophageal pressure is about the same as intraabdominal pressure.
p.49
Esophageal Motility and Peristalsis
What happens to the pressure at the upper esophageal sphincter (UES) during swallowing?
During swallowing, the movement of food to the pharynx increases pressure at the UES up to 100 mmHg.
p.50
Nervous System Control of GI Functions
What is the role of the myenteric plexus in the esophagus?
It helps regulate peristalsis, especially in the smooth muscle sections.
p.13
Nervous System Control of GI Functions
What types of neurons are found in the Myenteric Plexus?
Excitatory and inhibitory neurons.
p.21
Hormonal Regulation in the GI Tract
What role does secretin play in the gastrointestinal system?
Secretin stimulates the pancreas to release bicarbonate-rich fluid to neutralize the acidic chyme entering the small intestine from the stomach.
p.2
Components of the Gastrointestinal Tract
What are the hollow organs of the gastrointestinal tract?
The hollow organs of the gastrointestinal tract include the oropharynx (mouth), esophagus, stomach, gallbladder, duodenum, jejunum, ileum, colon, and rectum.
p.9
Nervous System Control of GI Functions
What is the effect of sympathetic stimulation on motor and secretory activity in the gut?
Sympathetic stimulation decreases motor and secretory activity in the gut.
p.57
Esophageal Motility and Peristalsis
What happens when the smooth muscle portion of the esophagus is placed in a tissue chamber and stimulated?
It exhibits peristaltic movement.
p.57
Esophageal Motility and Peristalsis
Is the central nervous system (CNS) required for peristalsis in the esophagus?
No, the CNS is not required for peristalsis.
p.50
Components of the Gastrointestinal Tract
What type of muscle is found in the middle esophagus?
Mixed striated and smooth muscle.
p.13
Nervous System Control of GI Functions
What type of innervation does the Myenteric Plexus provide to the longitudinal and circular muscles?
Excitatory and inhibitory innervation.
p.5
Esophageal Motility and Peristalsis
What are the common symptoms of achalasia?
Common symptoms of achalasia include difficulty in swallowing (dysphagia) and the formation of a bag-like protrusion in the esophagus.
p.25
Immune Function in the GI Tract
What role does Peyer's Patch play in the GALT system?
Peyer's Patch contains antigenic material and acts as the afferent (sensory) limb of the system.
p.25
Immune Function in the GI Tract
Why is it important for the GALT system to cease activity once the antigen is cleared?
It is important for the system to cease to prevent unnecessary immune responses that could damage the host's own tissues.
p.2
Components of the Gastrointestinal Tract
What is the function of the Sphincter of Oddi?
The Sphincter of Oddi controls the flow of digestive juices (bile and pancreatic juice) through the ducts from the liver and pancreas into the duodenum.
p.44
Nervous System Control of GI Functions
What effect does chewing gum have on salivary secretion?
Chewing gum increases salivary secretion.
p.87
Pathophysiology of GI Disorders
What is an antrectomy?
The removal of the antral part of the stomach.
p.46
Functions of the GI Tract
What triggers the excitation-contraction process in smooth muscle?
Depolarization, hormones, and neurotransmitters.
p.61
Gastroesophageal Reflux Disease (GERD)
What were the findings from the diagnostic procedures?
Hypotensive lower esophageal sphincter (LES) pressure and mild GERD.
p.29
Nervous System Control of GI Functions
Which cranial nerves provide afferent input to the swallowing center?
The 5th (trigeminal), 9th (glossopharyngeal), and 10th (vagus) cranial nerves.
p.50
Components of the Gastrointestinal Tract
What is the function of the upper esophageal sphincter?
It controls the passage of food from the pharynx into the esophagus.
p.23
Nervous System Control of GI Functions
What are the two types of activities mentioned in relation to muscular contraction?
Electrical Activity and Mechanical Activity.
p.25
Immune Function in the GI Tract
Which cells act as the efferent limb of the GALT system?
Cells in the lamina propria, such as mast cells and macrophages, act as the efferent limb of the system.
p.26
Hormonal Regulation in the GI Tract
What did the blood tests reveal about the patient's condition?
An increase in the levels of gastrin.
p.59
Esophageal Motility and Peristalsis
How is the propagation of the peristaltic wave in the esophagus related to the latency gradient?
The propagation of the peristaltic wave is related to the latency gradient in the esophageal circular smooth muscle.
p.42
Pathophysiology of GI Disorders
What type of cells infiltrate tissues in Sjogren's Syndrome?
Lymphocytes infiltrate tissues in Sjogren's Syndrome.
p.38
Gastroesophageal Reflux Disease (GERD)
Why is bicarbonate important in preventing esophageal injury?
Bicarbonate neutralizes stomach acid, protecting the esophagus from acid damage.
p.87
Gastric Secretions and Their Regulation
What is a significant consequence of losing gastrin release after an antrectomy?
Loss of HCl acid production.
p.57
Esophageal Motility and Peristalsis
What are the different muscle types involved in the control of esophageal peristalsis?
Smooth muscle, striated muscle, and mixed muscle.
p.61
Esophageal Motility and Peristalsis
Which option is NOT a primary genesis of LES pressure in adults?
Tonic excitatory sympathetic nerve input to the smooth muscle.
p.5
Esophageal Motility and Peristalsis
What causes the failure of the LES to relax in achalasia?
The failure of the LES to relax in achalasia is caused by the loss of Vagal Inhibitory Fibers (VIF), which are responsible for preventing relaxation of the LES.
p.25
Immune Function in the GI Tract
What is the Gut-Associated Lymphoid Tissue (GALT) and its primary function?
The intestine contains a mucosal immune system known as GALT, which acts as a barrier between the host and potentially harmful/toxic agents.
p.62
Esophageal Motility and Peristalsis
What is the function of the upper esophageal sphincter?
The upper esophageal sphincter controls the passage of food from the pharynx into the esophagus and prevents air from entering the esophagus during breathing.
p.59
Esophageal Motility and Peristalsis
What is the relationship between latency and the number of inhibitory neurotransmitters in esophageal circular smooth muscle?
Short latency is associated with less NO (Nitric Oxide), while long latency is associated with more NO.
p.38
Pathophysiology of GI Disorders
What did the endoscopic examination reveal in the patient's distal esophagus?
Erosions and scarring just above (orad) to the lower esophageal sphincter.
p.43
Nervous System Control of GI Functions
Why do many medications produce dry mouth?
Many medications produce dry mouth because they have muscarinic antagonist properties.
p.70
Gastric Motility and Emptying
How does the volume of a meal affect gastric emptying?
The stomach empties in proportion to the volume of the meal.
p.49
Esophageal Motility and Peristalsis
What are the three types of muscle found in the esophagus and where are they located?
The esophagus consists of skeletal muscle in the upper third, mixed muscle in the middle third, and smooth muscle in the lower third.
p.65
Gastric Secretions and Their Regulation
What did William Beaumont observe about gastric juices?
He observed the composition and control of gastric juices, noting factors such as temperature, exercise, and emotion.
p.65
Gastric Secretions and Their Regulation
What is the role of gastric acid in digestion?
Gastric acid, primarily hydrochloric acid (HCL) produced by the stomach lining, digests food. This process is a chemical event, not purely mechanical.
p.65
Gastric Secretions and Their Regulation
How much gastric secretion does the stomach produce daily?
The stomach secretes about 1 to 2 liters of gastric juice per day.
p.66
Components of the Gastrointestinal Tract
What is the function of the cardia region of the stomach?
The cardia is where the esophagus joins the stomach and contains cardiac glands that secrete mucus for protection.
p.82
Gastric Secretions and Their Regulation
What triggers the cephalic phase of gastric secretion?
The thought, smell, or taste of food triggers the cephalic phase, which accounts for about 30% of gastric secretions, involving acetylcholine (Ach) and gastrin.
p.77
Gastric Secretions and Their Regulation
What is the function of bicarbonate in the stomach?
Bicarbonate buffers the stomach acid.
p.8
Nervous System Control of GI Functions
Which regions of the spinal cord are involved in the parasympathetic innervation of the GI tract?
Cranial and Sacral regions.
p.67
Esophageal Motility and Peristalsis
What triggers the contraction of GI smooth muscle?
Contraction of GI smooth muscle occurs when action potentials are generated.
p.32
Nervous System Control of GI Functions
What does the sensory homunculus represent?
It represents areas of sensory information in the brain.
p.41
Pathophysiology of GI Disorders
Which glands are inflamed in mumps?
One or both parotid glands.
p.83
Hormonal Regulation in the GI Tract
What is the role of CCK-B receptors in the gastrointestinal system?
CCK-B receptors are involved in the regulation of gastric acid secretion and are primarily activated by gastrin.
p.9
Nervous System Control of GI Functions
What areas of the body does the sympathetic division innervate?
The sympathetic division innervates most areas of the gut.
p.2
Components of the Gastrointestinal Tract
What types of muscles are found in the gastrointestinal tract?
The gastrointestinal tract contains both smooth muscle and skeletal muscle.
p.2
Components of the Gastrointestinal Tract
What is the role of sphincters in the gastrointestinal tract?
Sphincters in the gastrointestinal tract regulate the passage of food and digestive juices between different sections of the tract, ensuring proper digestion and absorption.
p.87
Pathophysiology of GI Disorders
What conditions can an antrectomy be associated with?
Ulcers, gastric bleeding, tears, blockage, and/or cancer of the antral portion of the stomach.
p.29
Nervous System Control of GI Functions
Where is the swallowing center located?
In the pons and medulla of the brainstem.
p.71
Pathophysiology of GI Disorders
What is nausea?
Nausea is the sensation that vomiting will occur and is often accompanied by intense salivation.
p.70
Gastric Motility and Emptying
How does osmolality influence gastric emptying?
Hypertonic or hypotonic solutions empty slower than isotonic solutions due to osmoreceptors in the duodenum.
p.71
Hormonal Regulation in the GI Tract
What are some causes of pregnancy-related nausea?
Pregnancy-related nausea is associated with HCG and/or GDF15, which are produced by the placenta/fetus.
p.65
Gastric Secretions and Their Regulation
What is the tonicity of gastric secretion compared to plasma?
Gastric secretion is isotonic to plasma.
p.77
Gastric Secretions and Their Regulation
How does mucus contribute to gastric function?
Mucus lubricates and protects the stomach lining by entrapping bicarbonate.
p.64
Pathophysiology of GI Disorders
What is the significance of metaplastic change in the esophagus?
It indicates a transformation of cell types, which can be a response to chronic irritation and may increase the risk of esophageal cancer.
p.66
Components of the Gastrointestinal Tract
What is the main role of the corpus (body) of the stomach?
The corpus is the main functional part of the stomach, responsible for acid secretion through parietal cells.
p.82
Gastric Secretions and Their Regulation
What causes the gastric phase of gastric secretion?
The gastric phase is caused by the distention (irritation) of the stomach and accounts for about 50% of gastric secretions, involving gastrin, acetylcholine (Ach), and histamine.
p.1
Nervous System Control of GI Functions
Which parts of the nervous system are involved in controlling GI functions?
The sympathetic nervous system, parasympathetic nervous system, and enteric nervous system.
p.47
Components of the Gastrointestinal Tract
What is the size and nucleus characteristic of smooth muscle cells?
Smooth muscle cells are the smallest of the muscle types and have a single nucleus.
p.75
Gastric Secretions and Their Regulation
What do parietal (oxyntic) cells secrete and where are they located?
Parietal (oxyntic) cells secrete hydrochloric acid (HCl) and intrinsic factor, and are located in the glands of the cardia, fundus, and corpus of the stomach.
p.56
Nervous System Control of GI Functions
What is the role of the nucleus ambiguus in esophageal peristalsis?
The nucleus ambiguus is involved in the neural control of peristalsis in the striated muscle portion of the esophagus.
p.54
Nervous System Control of GI Functions
What is the role of the nucleus ambiguus in esophageal peristalsis?
It is involved in the neural control of peristalsis in the striated muscle portion of the esophagus.
p.21
Hormonal Regulation in the GI Tract
What is the primary stimulus for the release of secretin?
The presence of acidic chyme (low pH) in the small intestine.
p.38
Pathophysiology of GI Disorders
What condition is the 50-year-old female patient suffering from that affects her eyes?
Severe dryness of her eyes due to inadequate tear production.
p.9
Nervous System Control of GI Functions
What neurotransmitter is directly involved in the sympathetic division's effect on the gut?
Norepinephrine is the neurotransmitter involved.
p.40
Pathophysiology of GI Disorders
What are some common symptoms of xerostomia?
Dry mouth, food tasting tasteless, chronic infections of buccal mucosa, tooth decay, difficulty swallowing, and esophageal erosions.
p.9
Nervous System Control of GI Functions
What percentage of sympathetic division fibers are afferent, and what is their function?
50% of sympathetic division fibers are afferent, sending signals back to the spinal cord via the pre-vertebral ganglion.
p.74
Gastric Motility and Emptying
What is the role of the mixing and grinding movements in the stomach?
To break down food and move contents, including foreign objects like a swallowed quarter, towards the intestines.
p.40
Pathophysiology of GI Disorders
What percentage of patients on medication experience xerostomia?
20% of patients on medication.
p.65
Gastric Secretions and Their Regulation
Who was William Beaumont, M.D. and what was his contribution to the study of gastric secretions?
William Beaumont was a doctor who treated Alexis St. Martin for a gunshot wound in the stomach, leading to the creation of a gastric fistula. He observed the composition and control of gastric juices.
p.87
Pathophysiology of GI Disorders
What are some possible complications following an antrectomy?
Gastric and intestinal inflammation/infection, nausea, and vomiting.
p.79
Gastric Secretions and Their Regulation
What is the consequence of losing parietal cells in the stomach?
Loss of parietal cells leads to a loss of HCl production and intrinsic factor, which are essential for digestion and vitamin B12 absorption.
p.52
Esophageal Motility and Peristalsis
What is the role of the nucleus ambiguus in esophageal peristalsis?
The nucleus ambiguus coordinates the firing of motor nerves in the proximal portion of the esophagus, ensuring a coordinated contraction.
p.45
Functions of the GI Tract
What happens when calcium binds to troponin-C in skeletal muscle?
Tropomyosin no longer inhibits actin/myosin interaction.
p.66
Components of the Gastrointestinal Tract
What is the primary function of the fundus region of the stomach?
The fundus serves as a gas storage/trap area.
p.73
Gastric Motility and Emptying
What are the cycles of intense contractions of the stomach and small intestine during fasting called?
Migrating Motor Complex (MMC) or Migrating Myoelectric Complex.
p.1
Functions of the GI Tract
Which systems control the functions of the GI tract?
The functions of the GI tract are controlled by the nervous system and hormones.
p.68
Components of the Gastrointestinal Tract
What is the role of quiescent cells in the stomach?
Quiescent cells are less active and have a lower level of excitability.
p.31
Esophageal Motility and Peristalsis
What is the swallowing reflex?
The swallowing reflex is an involuntary action that moves food from the mouth through the pharynx and esophagus to the stomach.
p.82
Gastric Secretions and Their Regulation
What triggers the intestinal phase of gastric secretion?
The presence of food in the duodenum triggers the intestinal phase, which involves gastrin but is overwhelmed by inhibitory pathways such as CCK, GIP, and Secretin, accounting for less than 5% of gastric secretions.
p.19
Hormonal Regulation in the GI Tract
What triggers the release of somatostatin and what is its function?
Somatostatin is released by D cells in response to glucose, fats, and bile salts in the intestinal lumen, and it inhibits the secretion of gastrin.
p.55
Nervous System Control of GI Functions
What is the role of the nucleus ambiguus in esophageal peristalsis?
The nucleus ambiguus is involved in the control of peristalsis in the striated muscle portion of the esophagus.
p.62
Esophageal Motility and Peristalsis
What is an esophageal spasm?
An esophageal spasm is a sudden, painful contraction of the muscles in the esophagus.
p.42
Pathophysiology of GI Disorders
What are the primary symptoms of Sjogren's Syndrome?
Dryness of mucus membranes and skin, lymphocyte infiltration, and a decrease in salivary secretions.
p.2
Components of the Gastrointestinal Tract
What are the solid organs of the gastrointestinal tract?
The solid organs of the gastrointestinal tract include the salivary glands, liver, and pancreas.
p.26
Pathophysiology of GI Disorders
What did the CT scan reveal in the patient?
A tumor at the head of the pancreas.
p.43
Nervous System Control of GI Functions
What stimulates M3 receptors and what blocks them?
M3 receptors are stimulated by acetylcholine and blocked by atropine.
p.44
Nervous System Control of GI Functions
How does a dental exam affect salivary secretion?
A dental exam can increase salivary secretion due to nervous stimulation.
p.61
Esophageal Motility and Peristalsis
What diagnostic procedures were performed on the patient?
Measurement of esophageal pressure and endoscopic examination.
p.44
Nervous System Control of GI Functions
What is the effect of exposure to a nauseating odor on salivary secretion?
Exposure to a nauseating odor can increase salivary secretion.
p.42
Pathophysiology of GI Disorders
How does Sjogren's Syndrome affect salivary secretions?
Sjogren's Syndrome causes a decrease in salivary secretions.
p.15
Nervous System Control of GI Functions
What functions does the submucosal plexus control in the gastrointestinal tract?
The submucosal plexus controls GI secretions and blood flow.
p.29
Nervous System Control of GI Functions
How can a stroke affect the swallowing reflex?
A stroke can damage upper motor neurons, altering the transmission of signals from the brain to the swallowing muscles.
p.71
Pathophysiology of GI Disorders
What is retching?
Retching is when the contents of the stomach (duodenum) are moved into the esophagus, but do not reach the pharynx, resulting in dry heaves.
p.79
Gastric Secretions and Their Regulation
What happens when there is a loss of HCl production in the stomach?
Without HCl, pepsinogen cannot be converted to pepsin, impairing protein digestion.
p.29
Nervous System Control of GI Functions
What are the primary goals of the swallowing reflex?
To prevent food from entering the nose, trachea, and mouth.
p.52
Esophageal Motility and Peristalsis
What happens when the entire bundle of motor nerves in the esophagus is stimulated simultaneously?
The whole segment of the esophagus will contract, leading to a loss of coordination.
p.49
Esophageal Motility and Peristalsis
What is a primary peristaltic wave and its effect on intra-esophageal pressure?
A primary peristaltic wave is a coordinated muscle contraction that increases intra-esophageal pressure by 30-100 mmHg to move the bolus of food down the esophagus.
p.52
Nervous System Control of GI Functions
Why is input from the CNS required for esophageal contraction?
Input from the CNS is required to coordinate the firing of motor nerves, ensuring a coordinated contraction of the esophagus.
p.33
Components of the Gastrointestinal Tract
What type of solution do the parotid glands secrete?
Serous solution (water, enzymes, ions)
p.51
Nervous System Control of GI Functions
What is the primary source of innervation for the esophagus?
The esophagus is innervated by the vagus nerve (NA) and the dorsal motor nucleus (DMN).
p.62
Esophageal Motility and Peristalsis
What is peristalsis?
Peristalsis is a series of wave-like muscle contractions that move food through the digestive tract.
p.83
Hormonal Regulation in the GI Tract
What is the function of gastrin in the gastrointestinal tract?
Gastrin stimulates the secretion of gastric acid by the stomach's parietal cells.
p.83
Hormonal Regulation in the GI Tract
Why would a loss of CCK-B receptors lead to increased levels of gastrin?
The loss of CCK-B receptors would impair the feedback mechanism that regulates gastrin secretion, leading to increased circulating levels of gastrin.
p.42
Pathophysiology of GI Disorders
What causes the dryness of mucus membranes in Sjogren's Syndrome?
The dryness is caused by an autoimmune response that affects the glands producing mucus.
p.74
Gastric Motility and Emptying
Why did the physician reassure the father that the swallowed quarter would pass?
Because the mixing and grinding movements in the stomach would eventually move the quarter into the intestines.
p.70
Gastric Motility and Emptying
How does particle size affect gastric emptying?
Liquids empty faster than solids, and indigestible solids empty the slowest.
p.15
Nervous System Control of GI Functions
Which agents influence the submucosal plexus?
The release of agents including 5-HT (serotonin) and histamine (from mast cells) influences the submucosal plexus.
p.40
Pathophysiology of GI Disorders
Which medications are commonly associated with causing xerostomia?
Anti-depressants and radiation therapy.
p.40
Pathophysiology of GI Disorders
How does decreased salivary secretion affect oral health?
It causes a decrease in pH, leading to tooth decay and esophageal erosions.
p.45
Functions of the GI Tract
To which protein does calcium bind during skeletal muscle contraction?
Troponin-C (thin filament).
p.82
Gastric Secretions and Their Regulation
What is the basal or interdigestive period in gastric secretion?
It is a phase where a small amount of gastric secretion occurs over a long period of time, accounting for 15% of total secretions, due to a small basal release of gastrin.
p.8
Nervous System Control of GI Functions
Which part of the central nervous system is associated with the parasympathetic division for GI tract innervation?
The Dorsal Motor Nucleus of the Vagus.
p.52
Esophageal Motility and Peristalsis
What happens to the lower esophageal sphincter (LES) during a primary peristaltic wave?
The LES relaxes during the approaching pressure wave.
p.17
Hormonal Regulation in the GI Tract
What is autocrine signaling?
Autocrine signaling is a form of cell signaling where a cell secretes a hormone or chemical messenger that binds to receptors on the same cell, leading to changes in the cell.
p.77
Gastric Secretions and Their Regulation
Why is intrinsic factor important in the stomach?
Intrinsic factor is necessary for the absorption of Vitamin B12.
p.19
Hormonal Regulation in the GI Tract
How do paracrines function in the gastrointestinal system?
Paracrines are released by endocrine cells within the mucosa and diffuse through the extracellular space to their target cells.
p.68
Components of the Gastrointestinal Tract
What is the role of active cells in the stomach?
Active cells have a higher level of excitability and play an increased role in motility.
p.7
Nervous System Control of GI Functions
What is the role of postganglionic neurons in the autonomic nervous system?
Postganglionic neurons transmit nerve impulses from a ganglion to the target organ.
p.48
Functions of the GI Tract
What is the primary function of mixing movements in the GI tract?
To increase surface area for digestion and absorption.
p.34
Functions of the GI Tract
What role does saliva play in tissue repair?
Saliva contains Epidermal Growth Factor which aids in tissue repair.
p.7
Nervous System Control of GI Functions
Which division of the autonomic nervous system is responsible for 'rest and digest' functions in the GI tract?
The parasympathetic nervous system.
p.34
Functions of the GI Tract
What are the antibacterial components of saliva?
Lactoferrin and lysozyme.
p.28
Functions of the GI Tract
What role does food in the mouth play in the chewing reflex?
Food in the mouth (palate) helps to stimulate the chewing reflex.
p.27
Gastroesophageal Reflux Disease (GERD)
What lifestyle habit does the patient admit to that could exacerbate her symptoms?
Smoking a pack of cigarettes per day for the past 15 years.
p.21
Hormonal Regulation in the GI Tract
What is the function of gastrin in the gastrointestinal system?
Gastrin stimulates the secretion of gastric acid (HCl) by the stomach.
p.40
Pathophysiology of GI Disorders
What is xerostomia?
Xerostomia is a condition characterized by dry mouth.
p.46
Functions of the GI Tract
What is the role of calcium/calmodulin (Ca/CM) in smooth muscle contraction?
It allows cross-bridge formation between actin and myosin.
p.15
Nervous System Control of GI Functions
What types of neurons are contained in the submucosal plexus?
Sensory afferent neurons, interneurons, and neurons that project to the muscularis mucosae (motor) and the gut epithelium (secretion).
p.15
Nervous System Control of GI Functions
What type of innervation does the submucosal plexus provide to the epithelium and muscularis mucosae?
It provides both excitatory and inhibitory innervation to the epithelium and muscularis mucosae.
p.44
Nervous System Control of GI Functions
How does resting conditions affect salivary secretion compared to sleep?
Resting conditions have higher rates of salivary secretion compared to sleep.
p.3
Gastroesophageal Reflux Disease (GERD)
What is Gastroesophageal Reflux Disease (GERD)?
GERD is a condition where the lower esophageal sphincter (LES) fails to contract properly after food moves into the stomach, leading to acid reflux.
p.57
Esophageal Motility and Peristalsis
What are the abbreviations UES and LES in the context of esophageal peristalsis?
UES stands for Upper Esophageal Sphincter and LES stands for Lower Esophageal Sphincter.
p.77
Gastric Secretions and Their Regulation
What are the functions of hydrochloric acid (HCL) in the stomach?
HCL converts pepsinogen to pepsin, kills bacteria, and denatures protein.
p.1
Functions of the GI Tract
How much food does an average person consume per day?
About 4.5 pounds of food per day.
p.70
Nervous System Control of GI Functions
What is the enterogastric reflex and how does it affect gastric emptying?
The enterogastric reflex involves chemical and mechanical stimuli that slow down gastric emptying.
p.19
Nervous System Control of GI Functions
Where are neurocrines synthesized and how are they released?
Neurocrines are synthesized in the cell bodies of neurons, migrate to the axonal ending, and are released by an action potential.
p.52
Esophageal Motility and Peristalsis
What is the role of gravity in esophageal peristalsis?
Gravity assists in the movement of the bolus down the esophagus during peristalsis.
p.75
Gastric Secretions and Their Regulation
Where are G cells located and what do they secrete?
G cells are located in the glands of the pyloric antrum and they secrete gastrin.
p.33
Components of the Gastrointestinal Tract
What type of secretion do the submandibular glands produce?
Mixed glands (mucus and serous)
p.28
Nervous System Control of GI Functions
Which cranial nerve innervates the muscles involved in mastication?
The motor branch of the 5th cranial nerve.
p.36
Components of the Gastrointestinal Tract
How does chloride (Cl-) move during the production of saliva?
Chloride (Cl-) moves into the acinar cell and then into the lumen.
p.11
Nervous System Control of GI Functions
What is the Enteric Nervous System (ENS) also known as?
The Intrinsic Nervous System.
p.66
Components of the Gastrointestinal Tract
What is the role of the pyloric valve in the stomach?
The pyloric valve is an anatomical sphincter that regulates the passage of stomach contents into the small intestine.
p.66
Components of the Gastrointestinal Tract
Are nutrients absorbed in the stomach?
No, the stomach does not absorb nutrients, except for certain substances like aspirin and alcohol.
p.28
Nervous System Control of GI Functions
What reflex is triggered by the excitation of stretch receptors in the jaw?
The stretch reflex, which causes the jaw to close.
p.58
Esophageal Motility and Peristalsis
What is the significance of the 'duration response' in esophageal smooth muscle?
The 'duration response' refers to the sustained contraction phase due to acetylcholine (Ach) release.
p.30
Esophageal Motility and Peristalsis
How is the bolus of food moved through the pharynx during swallowing?
Contraction of pharyngeal muscles forces the bolus through the pharynx and enlarges the esophagus.
p.80
Hormonal Regulation in the GI Tract
What are prostanoids and how do they affect acid secretion?
Prostanoids, including Cox-1 and Cox-2, suppress histamine and thus inhibit acid secretion.
p.80
Hormonal Regulation in the GI Tract
At what pH levels in the stomach and duodenum is gastrin secretion shut off?
Stomach pH < 1.5 and duodenum pH 3-4.
p.30
Esophageal Motility and Peristalsis
What are the primary and secondary peristaltic waves in the esophageal stage?
Primary peristaltic waves are initiated by swallowing, while secondary waves are inherent to the smooth muscle of the esophagus.
p.50
Components of the Gastrointestinal Tract
What are the three sections of the human esophagus?
Upper, middle, and lower.
p.57
Esophageal Motility and Peristalsis
What role does the dorsal motor nucleus (DMN) play in the motility of smooth muscle in the esophagus?
The DMN plays no role in the motility of smooth muscle.
p.42
Pathophysiology of GI Disorders
Which other autoimmune disorders may be associated with Sjogren's Syndrome?
Sjogren's Syndrome may be associated with lupus and rheumatoid arthritis.
p.61
Esophageal Motility and Peristalsis
What is the primary genesis of LES pressure in adults?
Myogenic properties of LES smooth muscle.
p.70
Gastric Motility and Emptying
How does meal composition affect the rate of gastric emptying?
Meals high in glucose empty faster than those high in protein, which in turn empty faster than those high in fats.
p.40
Pathophysiology of GI Disorders
What are some treatments for xerostomia?
Artificial saliva and parasympathetic agonists.
p.79
Gastric Secretions and Their Regulation
Why is intrinsic factor important?
Intrinsic factor is crucial for the protection and absorption of vitamin B12 in the small intestine.
p.65
Gastric Secretions and Their Regulation
What are the two distinct components of gastric secretions?
The two distinct components are basal secretion, which is continuous, and a stimulated component that is rich in H+ ions produced by parietal cells.
p.75
Gastric Secretions and Their Regulation
What is the primary function of mucus neck cells in the stomach?
Mucus neck cells, located in the neck of the gland, secrete mucus.
p.68
Components of the Gastrointestinal Tract
What are the functional regions of the stomach?
The functional regions of the stomach are the fundus, corpus, antrum, and pyloric ring.
p.7
Nervous System Control of GI Functions
What type of nervous system controls voluntary actions?
The voluntary nervous system.
p.64
Gastroesophageal Reflux Disease (GERD)
What are potential treatments for the patient's condition?
Treatment may include proton pump inhibitors (PPIs) to reduce stomach acid, lifestyle changes such as diet modification, and possibly surgical intervention if a fistula is confirmed.
p.88
Gastric Motility and Emptying
What is the role of nitric oxide in maintaining gastric pressure-volume relationship?
Nitric oxide helps in relaxing the stomach muscles, allowing the stomach to accommodate increased volume without a significant rise in pressure.
p.75
Gastric Secretions and Their Regulation
What is the function of chief (peptic) cells in the stomach?
Chief (peptic) cells secrete pepsinogen and are located in the glands of the cardia, fundus, and corpus.
p.36
Components of the Gastrointestinal Tract
What type of transport is involved in moving Na+ out of the acinar cell?
Active transport via the Na/K ATPase pump.
p.11
Nervous System Control of GI Functions
What are the two main plexuses of the Enteric Nervous System?
The Myenteric (Auerbach’s) Plexus and the Submucosal (Meissner’s) Plexus.
p.68
Components of the Gastrointestinal Tract
Which region of the stomach has the least excitable cells?
The pyloric ring has the least excitable cells with a membrane potential of -75mV.
p.36
Components of the Gastrointestinal Tract
What type of transport is involved in moving HCO3- and K+ into the lumen?
Secondary active transport.
p.47
Components of the Gastrointestinal Tract
Where are smooth muscle cells generally found?
Smooth muscle cells are generally found lining organs or forming organs such as blood vessels, the eye, bladder, GI tract, and uterus.
p.69
Gastric Motility and Emptying
Where do low-frequency contractions that generate basal pressure of the stomach occur?
In the fundus and upper corpus (body) of the stomach.
p.34
Functions of the GI Tract
What is the role of salivary amylase?
Salivary amylase begins the digestion of carbohydrates in the mouth.
p.47
Components of the Gastrointestinal Tract
How is contraction in the gut governed in smooth muscle cells?
In the gut, contraction of smooth muscle cells is governed by slow waves.
p.34
Functions of the GI Tract
How does saliva buffer acids in the mouth, esophagus, and stomach?
Saliva contains bicarbonate buffers that neutralize H+ ions.
p.72
Nervous System Control of GI Functions
How do pain and emotion affect gastric motility?
Pain and emotion can influence gastric motility through neuronal factors via the CNS.
p.72
Gastric Motility and Emptying
What is receptive relaxation in the context of gastric motility?
Receptive relaxation is the process where the stomach relaxes to accommodate incoming food, mediated by intrinsic nerve pathways.
p.26
Pathophysiology of GI Disorders
What is the initial treatment for the patient's condition?
The patient is referred for surgery to remove the tumor.
p.57
Esophageal Motility and Peristalsis
What type of muscle event is mostly involved in esophageal peristalsis?
Mostly a circular muscle event.
p.43
Nervous System Control of GI Functions
What is Eserine (physostigmine) used to treat?
Eserine (physostigmine) is used to treat glaucoma and delayed gastric emptying (gastroparesis).
p.43
Nervous System Control of GI Functions
What is Sarin and what is its effect on the nervous system?
Sarin is a nerve gas that inhibits acetylcholinesterase, leading to increased acetylcholine levels.
p.8
Nervous System Control of GI Functions
What are the two main divisions of the extrinsic innervation of the GI tract?
Parasympathetic Division and Sympathetic Division.
p.70
Hormonal Regulation in the GI Tract
Which hormones are involved in regulating gastric emptying?
CCK (cholecystokinin), secretin, GIP (gastric inhibitory peptide), and gastrin.
p.64
Pathophysiology of GI Disorders
What was revealed in the view of the patient's lower esophagus?
Mucosal inflammation with evidence of a potential fistula.
p.78
Gastric Secretions and Their Regulation
What role do chloride ions play in gastric acid secretion?
Chloride ions are involved in anion exchange and contribute to the formation of hydrochloric acid in the stomach.
p.82
Gastric Motility and Emptying
What effect does the cephalic phase have on gastric motility?
The cephalic phase may produce a small increase in gastric motility.
p.64
Gastroesophageal Reflux Disease (GERD)
What condition might be suggested by the combination of chest pain, persistent cough, bronchospasm, and mucosal inflammation in the esophagus?
Gastroesophageal Reflux Disease (GERD) with possible complications such as esophagitis or a fistula.
p.28
Nervous System Control of GI Functions
Which reflex centers coordinate the process of mastication?
Reflex centers that facilitate the opening and closing of the mouth.
p.7
Nervous System Control of GI Functions
What are the two types of neurons involved in the autonomic nervous system?
Preganglionic and postganglionic neurons.
p.7
Nervous System Control of GI Functions
What is the role of preganglionic neurons in the autonomic nervous system?
Preganglionic neurons transmit nerve impulses from the central nervous system to a ganglion.
p.31
Esophageal Motility and Peristalsis
Which phases are involved in the swallowing reflex?
The swallowing reflex involves three phases: the oral phase, the pharyngeal phase, and the esophageal phase.
p.34
Functions of the GI Tract
How much saliva is produced daily?
0.5 - 1.5 liters per day.
p.19
Hormonal Regulation in the GI Tract
What is the role of histamine in the gastrointestinal system?
Histamine, released by mast cells, stimulates acid secretion by parietal cells and acts as a co-factor with acetylcholine and gastrin.
p.80
Hormonal Regulation in the GI Tract
What role does histamine play in the regulation of acid secretion?
Histamine potentiates acid secretion by acting as a co-factor and binding to H2 receptors.
p.27
Gastroesophageal Reflux Disease (GERD)
What are the primary symptoms presented by the 60-year-old female patient?
Heartburn and chest pain.
p.75
Gastric Secretions and Their Regulation
What is the role of stem cells in the gastric glands?
Stem cells in the gastric glands are responsible for replacing existing cells.
p.11
Nervous System Control of GI Functions
What is the primary function of the Submucosal (Meissner’s) Plexus?
To control GI secretions and blood flow.
p.48
Esophageal Motility and Peristalsis
Which neurotransmitters are involved in relaxing longitudinal smooth muscle during peristalsis?
Nitric oxide and VIP (vasoactive intestinal peptide).
p.30
Esophageal Motility and Peristalsis
Is gravity the main force moving the bolus towards the stomach during the esophageal stage?
No, it is primarily a muscular event.
p.6
Nervous System Control of GI Functions
What is the role of the enteric nervous system (ENS) in the GI tract?
The ENS controls local reflexes, regulates motility, secretion, and blood flow within the GI tract.
p.4
Gastroesophageal Reflux Disease (GERD)
What is the potential risk of untreated GERD?
Untreated GERD can increase the risk of developing esophageal cancer.
p.79
Gastric Secretions and Their Regulation
What is achlorhydria?
Achlorhydria is the absence of hydrochloric acid (HCl) in gastric secretions.
p.87
Pathophysiology of GI Disorders
What is gastric mucosal atrophy and how is it related to antrectomy?
Gastric mucosal atrophy is the thinning of the stomach lining, which can occur after an antrectomy.
p.61
Gastroesophageal Reflux Disease (GERD)
What condition is characterized by a hypotensive lower esophageal sphincter (LES) pressure?
Gastroesophageal Reflux Disease (GERD).
p.64
Pathophysiology of GI Disorders
What symptoms did the 38-year-old male present with?
Chest pain, persistent cough, and bronchospasm.
p.71
Esophageal Motility and Peristalsis
Why is reverse peristalsis alone not sufficient for vomiting?
Reverse peristalsis alone is not sufficient for vomiting because the pressure generated is not enough; contraction of abdominal muscles is also needed.
p.64
Pathophysiology of GI Disorders
What type of cellular change was observed in the patient's esophageal mucosal lining?
Metaplastic change from stratified, squamous, non-keratinizing cells to glandular columnar cells.
p.3
Gastroesophageal Reflux Disease (GERD)
What were some traditional treatments for GERD?
Traditional treatments included vagotomy (to reduce acid) and gastric resection, though these could lead to complications like dumping syndrome.
p.58
Esophageal Motility and Peristalsis
What are the two types of muscles involved in esophageal peristalsis?
Circular muscle and longitudinal muscle.
p.73
Gastric Motility and Emptying
What is the purpose of the Migrating Motor Complex?
To move 'debris' from the stomach and small intestine through the ileocecal valve and into the colon.
p.17
Hormonal Regulation in the GI Tract
What is endocrine signaling?
Endocrine signaling is a form of cell signaling where hormones are released into the bloodstream and travel to distant target cells throughout the body.
p.58
Esophageal Motility and Peristalsis
What is the 'off response' in esophageal smooth muscle contraction?
The 'off response' is a cryptogenic response related to the relaxation phase.
p.68
Components of the Gastrointestinal Tract
How does membrane potential vary across different regions of the stomach?
The membrane potential varies as follows: Fundus (-48mV), Corpus (-51mV), Antrum (-70mV), Pyloric Ring (-75mV).
p.7
Nervous System Control of GI Functions
What are the two divisions of the autonomic nervous system that innervate the GI tract?
The parasympathetic and sympathetic nervous systems.
p.28
Nervous System Control of GI Functions
What happens when the jaw opens during mastication?
Stretch receptors (muscle spindles) are excited.
p.80
Hormonal Regulation in the GI Tract
Which medications can block histamine's effect on acid secretion?
Pepcid (famotidine) and Tagamet (cimetidine).
p.7
Nervous System Control of GI Functions
Which division of the autonomic nervous system is responsible for 'fight or flight' responses in the GI tract?
The sympathetic nervous system.
p.67
Esophageal Motility and Peristalsis
What is the relationship between electrical and mechanical activity in GI smooth muscle?
Electrical activity, such as action potentials and spike potentials, triggers mechanical activity, which is the contraction of the muscle.
p.48
Esophageal Motility and Peristalsis
Which neurotransmitters are involved in contracting circular smooth muscle during peristalsis?
Acetylcholine and substance P.
p.11
Nervous System Control of GI Functions
Which neurotransmitters are considered inhibitory in the Enteric Nervous System?
Nitric oxide (NO), norepinephrine (NE), and vasoactive intestinal peptide (VIP).
p.37
Components of the Gastrointestinal Tract
What happens to sodium as saliva passes through the ductal cells?
Sodium is reabsorbed through Na+/H+ exchange (active) and ENaC.
p.37
Components of the Gastrointestinal Tract
How is chloride reabsorbed in the ductal cells?
Chloride is reabsorbed via the Cl/HCO3 exchanger, which is passive and involves recycling from the CFTR transporter.
p.6
Nervous System Control of GI Functions
What effect does the sympathetic nervous system have on the GI tract?
The sympathetic nervous system generally inhibits digestive activities, decreasing motility and secretion.
p.12
Nervous System Control of GI Functions
What type of fibers are preganglionic parasympathetic fibers?
Preganglionic parasympathetic fibers are part of the autonomic nervous system that typically release acetylcholine (Ach) to stimulate gastrointestinal movements.
p.60
Esophageal Motility and Peristalsis
What is responsible for the closing of the LES?
The closing of the LES is related to the intrinsic activity of the smooth muscle.
p.50
Components of the Gastrointestinal Tract
What is the function of the lower esophageal sphincter?
It prevents the backflow of stomach contents into the esophagus.
p.71
Pathophysiology of GI Disorders
What is emesis?
Emesis is the process of vomiting.
p.3
Gastroesophageal Reflux Disease (GERD)
What symptom is commonly associated with GERD?
A feeling of 'heartburn'.
p.3
Gastroesophageal Reflux Disease (GERD)
How does an increase in stomach pressure contribute to GERD?
Reflux occurs due to an increase in pressure (5 - 15 mmHg) in the stomach caused by contractions.
p.1
Functions of the GI Tract
What are the key processes involved in the function of the GI tract?
Secretion, motility, digestion, absorption, and immunity.
p.79
Pathophysiology of GI Disorders
What is pernicious anemia?
Pernicious anemia is a type of anemia caused by the body's inability to absorb vitamin B12, leading to the failure of RBCs to mature.
p.52
Nervous System Control of GI Functions
Which part of the nervous system is involved in stimulating esophageal peristalsis?
The vagal efferent nerves are involved in stimulating esophageal peristalsis.
p.66
Components of the Gastrointestinal Tract
What occurs in the antrum region of the stomach?
The antrum is involved in large intense contractions for emptying and secretes gastrin, somatostatin, and mucus.
p.63
Esophageal Motility and Peristalsis
What is achalasia?
Achalasia is a condition characterized by the failure of the lower esophageal sphincter (LES) to relax, often due to the loss of nitric oxide (NO).
p.73
Gastric Motility and Emptying
What are the phases of the Migrating Motor Complex?
Phase I: Quiescent period, Phase II: Increasing action potential frequency and peristalsis, Phase III: Peak time of intense contraction.
p.63
Esophageal Motility and Peristalsis
What are common symptoms of achalasia?
Common symptoms of achalasia include esophageal distension, dysphagia (difficulty swallowing), vomiting, and aspiration pneumonia.
p.88
Gastric Motility and Emptying
How does a cholinergic agonist affect gastric motility?
A cholinergic agonist increases gastric motility and could potentially increase gastric pressure.
p.58
Nervous System Control of GI Functions
What is the role of the myenteric plexus in esophageal motility?
The myenteric plexus regulates the peristaltic movements and coordination of muscle contractions in the esophagus.
p.69
Gastric Motility and Emptying
What is the difference between receptive relaxation and adaptive relaxation in the stomach?
Receptive relaxation is mediated by acetylcholine (Ach) and nitric oxide (NO), while adaptive relaxation occurs due to increased pressure in the fundus and is mediated by NO.
p.31
Esophageal Motility and Peristalsis
Describe the esophageal phase of the swallowing reflex.
During the esophageal phase, peristaltic waves move the food bolus down the esophagus and into the stomach.
p.7
Nervous System Control of GI Functions
What are the primary receptors found in the gut involved in autonomic nervous system regulation?
M2 (80%) and M3 (20%) receptors.
p.34
Functions of the GI Tract
How does saliva aid in chewing and swallowing?
Saliva lubricates the mouth and breaks apart food, making it easier to chew and swallow.
p.27
Gastroesophageal Reflux Disease (GERD)
What additional symptoms does the patient experience upon awakening?
Sore throat and raspy voice.
p.72
Gastric Motility and Emptying
What local neural circuits respond to in the context of gastric motility?
Local neural circuits respond to distension.
p.22
Nervous System Control of GI Functions
What are the Interstitial Cells of Cajal (ICC) responsible for in the GI tract?
They are responsible for generating the slow waves or Basal Electrical Rhythm (BER) in the GI smooth muscle.
p.22
Nervous System Control of GI Functions
What is the frequency of slow waves in the stomach, duodenum, and distal ileum?
3/min in the stomach, 10-20/min in the duodenum, and 8-10/min in the distal ileum.
p.76
Gastric Secretions and Their Regulation
What is the role of D cells in the pyloric glands?
D cells secrete somatostatin, which inhibits the release of gastrin and thus reduces acid secretion.
p.12
Nervous System Control of GI Functions
What type of fibers are postganglionic sympathetic fibers?
Postganglionic sympathetic fibers are part of the autonomic nervous system that typically release norepinephrine (NE) to inhibit gastrointestinal movements.
p.12
Nervous System Control of GI Functions
What is the function of the myenteric plexus (Auerbach’s plexus)?
The myenteric plexus (Auerbach’s plexus) is responsible for controlling gastrointestinal motility by coordinating the contraction of the longitudinal and circular muscles.
p.60
Pathophysiology of GI Disorders
What happens to the LES in the condition known as achalasia?
In achalasia, there is damage or loss of the myenteric plexus, leading to a loss of nitric oxide (NO) and impaired relaxation of the LES.
p.39
Nervous System Control of GI Functions
What factors inhibit salivary secretion under parasympathetic control?
Dehydration, fear, and sleep.
p.3
Gastroesophageal Reflux Disease (GERD)
What can cause the lower esophageal sphincter (LES) to fail in GERD?
Alterations in the enteric nervous system (ENS) or external factors such as caffeine, chocolate, nicotine, and alcohol.
p.49
Esophageal Motility and Peristalsis
What is the role of the upper esophageal sphincter (UES) during swallowing?
The increased pressure at the UES causes it to open, allowing food to move into the esophagus.
p.1
Functions of the GI Tract
What are the main types of food consumed by an average person?
Meat, dairy products, fats and oils, fruits and vegetables, grains/fiber, and sugar.
p.1
Functions of the GI Tract
What is the primary function of the gastrointestinal (GI) tract?
To provide a continual supply of water and nutrients to the body.
p.19
Nervous System Control of GI Functions
What are the effects of Vasoactive Intestinal Polypeptide (VIP) on the gastrointestinal system?
VIP causes smooth muscle cell relaxation, increasing GI blood flow, and decreases HCL secretion.
p.78
Gastric Secretions and Their Regulation
What is the role of water and CO2 in gastric acid secretion?
Water and CO2 combine to form carbonic acid, which dissociates into hydrogen and bicarbonate ions, contributing to the acidification process.
p.17
Hormonal Regulation in the GI Tract
What is paracrine signaling?
Paracrine signaling involves the release of hormones or chemical messengers by a cell that affect nearby target cells in the local environment.
p.75
Gastric Secretions and Their Regulation
What is the role of D cells in the stomach?
D cells, found in the antrum of the stomach, secrete somatostatin, which inhibits the secretion of gastrin.
p.78
Gastric Secretions and Their Regulation
What is the function of the H-K ATPase in gastric acid secretion?
The H-K ATPase, also known as the Proton Pump, actively exchanges hydrogen ions for potassium ions, facilitating the secretion of gastric acid.
p.17
Hormonal Regulation in the GI Tract
How do hormones travel in endocrine signaling?
In endocrine signaling, hormones travel through the bloodstream to reach distant target cells.
p.73
Gastric Motility and Emptying
What phenomenon during fasting may be explained by the Migrating Motor Complex?
The 'growling' of the stomach/intestine.
p.63
Esophageal Motility and Peristalsis
What causes the failure of the LES to relax in achalasia?
The failure of the LES to relax in achalasia is often caused by the damage or loss of the myenteric plexus.
p.69
Gastric Motility and Emptying
What role do weak peristaltic waves play in gastric motility?
They mix food to form chyme.
p.33
Functions of the GI Tract
What type of fluid is secreted by salivary glands besides enzymes and mucus?
Extracellular fluid (ECF)
p.30
Esophageal Motility and Peristalsis
What is generated during the pharyngeal stage to aid in swallowing?
A primary peristaltic wave.
p.4
Gastroesophageal Reflux Disease (GERD)
What is Barrett's esophagus and how is it related to GERD?
Barrett's esophagus is a condition where the esophageal lining changes, becoming similar to the lining of the intestine, and it can be caused by chronic GERD.
p.4
Gastroesophageal Reflux Disease (GERD)
How can GERD affect the respiratory system?
GERD can cause respiratory issues such as chronic cough, laryngitis, and asthma due to the aspiration of acid into the airways.
p.27
Gastroesophageal Reflux Disease (GERD)
What are some initial thoughts on the patient's condition based on her symptoms and habits?
The patient may be suffering from Gastroesophageal Reflux Disease (GERD), exacerbated by smoking, high BMI, and consumption of acidic and fatty foods.
p.27
Gastroesophageal Reflux Disease (GERD)
Why is the patient's smoking habit relevant to her symptoms?
Smoking can weaken the lower esophageal sphincter, leading to increased acid reflux and GERD symptoms.
p.72
Nervous System Control of GI Functions
What role do extrinsic nerve pathways play in gastric motility?
Extrinsic nerve pathways, including the vagovagal reflex, help regulate gastric motility by slowing down the stomach.
p.76
Gastric Secretions and Their Regulation
What do peptic (chief) cells secrete?
Peptic (chief) cells secrete pepsinogen, which is converted to pepsin in the acidic environment of the stomach.
p.22
Nervous System Control of GI Functions
What is the role of calcium channels in GI smooth muscle activity?
Calcium channels are involved in the generation of spike potentials, which are true action potentials necessary for muscle contraction.
p.84
Gastric Secretions and Their Regulation
What is the pH level in the lumen of the stomach?
The pH level in the lumen of the stomach is approximately 1.5.
p.84
Gastric Secretions and Their Regulation
What is the pH level in the plasma surrounding the stomach?
The pH level in the plasma is approximately 7.4.
p.77
Gastric Secretions and Their Regulation
What is the role of pepsinogen in gastric secretions?
Pepsinogen is converted to pepsin to partially digest proteins.
p.79
Pathophysiology of GI Disorders
What is the result of vitamin B12 not being protected and absorbed?
Failure to absorb vitamin B12 leads to the inability of red blood cells (RBCs) to mature properly, causing pernicious anemia.
p.78
Gastric Secretions and Their Regulation
How are hydrogen ions actively pumped into the lumen of the canaliculus?
Hydrogen ions are actively pumped into the lumen of the canaliculus in exchange for potassium ions via the H-K ATPase (Proton Pump).
p.88
Gastric Motility and Emptying
Which pharmacological agent could abolish the remarkable pressure-volume relationship in the stomach?
B. inhibitor of nitric oxide synthase.
p.36
Components of the Gastrointestinal Tract
What role does the Na/K ATPase pump play in the production of saliva?
It pumps sodium (Na+) out of the acinar cell.
p.1
Hormonal Regulation in the GI Tract
What role do hormones play in the GI tract?
Hormones help regulate the various functions of the GI tract.
p.28
Functions of the GI Tract
What are the primary functions of mastication?
To lubricate food with salivary secretions, increase surface area by breaking down cellulose membranes, and begin the digestion of carbohydrates and fats.
p.68
Components of the Gastrointestinal Tract
Which region of the stomach is the most excitable?
The fundus is the most excitable region with a membrane potential of -48mV.
p.33
Functions of the GI Tract
What digestive enzymes are secreted by salivary glands?
Alpha amylase and salivary lipase
p.30
Esophageal Motility and Peristalsis
What occurs during the pharyngeal stage of swallowing?
The soft palate elevates to close off the nasopharynx, and the pharynx and larynx are elevated.
p.63
Esophageal Motility and Peristalsis
What is Nutcracker Esophagus?
Nutcracker Esophagus is a condition characterized by hypertensive peristalsis, which is very painful but hard to localize due to its visceral nature.
p.47
Components of the Gastrointestinal Tract
What are the primary functions of smooth muscle cells?
The primary functions of smooth muscle cells are motility (e.g., in the gut) and maintaining tension (e.g., in blood vessels).
p.11
Nervous System Control of GI Functions
Is the Enteric Nervous System dependent on the Sympathetic Nervous System (SNS) and Parasympathetic Nervous System (PNS)?
No, it is independent of the SNS and PNS.
p.63
Esophageal Motility and Peristalsis
What is a key difference between coordinated and uncoordinated peristalsis in the context of esophageal disorders?
Coordinated peristalsis involves smooth, sequential muscle contractions, while uncoordinated peristalsis involves irregular, non-sequential contractions, often seen in conditions like Nutcracker Esophagus.
p.60
Esophageal Motility and Peristalsis
What is believed to be the mechanism behind the contraction of the LES?
The mechanism of contraction remains unclear but is probably related to the intrinsic myogenic tone of the muscle.
p.60
Esophageal Motility and Peristalsis
How can the relaxation of the LES be inhibited?
The relaxation of the LES can be inhibited by TTX (tetrodotoxin).
p.37
Components of the Gastrointestinal Tract
What role does the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) play in salivary secretion?
CFTR is involved in the recycling of chloride ions during the reabsorption process.
p.39
Nervous System Control of GI Functions
What stimuli are stimulatory for salivary secretion under parasympathetic control?
Taste, tactile stimuli, smell (cephalic phase), and nausea.
p.10
Nervous System Control of GI Functions
Where does the vagus nerve originate in the parasympathetic division?
In the Dorsal Motor Nucleus of the medulla in the brainstem.
p.10
Nervous System Control of GI Functions
What types of information do the sensory fibers of the vagus nerve transmit from the gut to the brain?
Information about glucose, pH, osmolality, and mechanical stimuli (level of stretch).
p.49
Esophageal Motility and Peristalsis
What happens when the bolus of food reaches the lower esophageal sphincter (LES)?
When the bolus of food reaches the LES, it relaxes to allow the food to enter the stomach.
p.3
Gastroesophageal Reflux Disease (GERD)
What are some modern treatments for GERD?
Modern treatments include antihistamines, proton pump inhibitors, and surgical options such as stitching or radio therapy.
p.78
Gastric Secretions and Their Regulation
How does water pass through the membrane during gastric acid secretion?
Water passes through the membrane via osmosis.
p.67
Esophageal Motility and Peristalsis
How is the duration of GI smooth muscle contraction determined?
The duration of contraction is related to the number of spike potentials.
p.45
Functions of the GI Tract
What is the role of the motor endplate in muscle contraction?
It receives the signal from the presynaptic nerve terminal to initiate muscle contraction.
p.67
Esophageal Motility and Peristalsis
What role does calcium play in GI smooth muscle activity?
Calcium entry is crucial for the contraction of GI smooth muscle.
p.47
Components of the Gastrointestinal Tract
Do smooth muscle cells have sarcomeres?
No, smooth muscle cells do not have sarcomeres.
p.48
Nervous System Control of GI Functions
What is required for propulsive movements in the GI tract?
An intact Myenteric Plexus.
p.31
Esophageal Motility and Peristalsis
What occurs during the pharyngeal phase of swallowing?
In the pharyngeal phase, the soft palate elevates to close off the nasopharynx, and the epiglottis covers the trachea to prevent food from entering the airway.
p.67
Esophageal Motility and Peristalsis
What are spike potentials in GI smooth muscle activity?
Spike potentials are rapid depolarizations that lead to muscle contractions.
p.48
Esophageal Motility and Peristalsis
What is peristalsis also known as?
The Law of the Gut, Peristaltic Reflex, or Myenteric Reflex.
p.58
Esophageal Motility and Peristalsis
What happens during the relaxation of the lower esophageal sphincter (LES)?
The LES relaxes to allow the passage of food from the esophagus into the stomach, a process mediated by nitric oxide (NO).
p.68
Components of the Gastrointestinal Tract
How does the level of excitability change from the fundus to the pyloric ring?
The level of excitability decreases from the fundus to the pyloric ring, with the fundus being the most excitable and the pyloric ring being the least excitable.
p.69
Gastric Motility and Emptying
What is the pyloric pump?
A mechanism that helps in the emptying of the stomach contents into the duodenum.
p.11
Nervous System Control of GI Functions
Can a single neuron in the Enteric Nervous System release more than one mediator?
Yes, a single neuron can release more than one mediator.
p.72
Hormonal Regulation in the GI Tract
What are enterogastrones and how do they influence gastric motility?
Enterogastrones are hormones that slow down gastric motility.
p.6
Nervous System Control of GI Functions
How does the autonomic nervous system (ANS) influence the GI tract?
The ANS modulates the activity of the ENS through sympathetic and parasympathetic inputs, affecting motility and secretion.
p.37
Components of the Gastrointestinal Tract
How is bicarbonate secreted in the ductal cells?
Bicarbonate is secreted by the Cl/HCO3 exchanger.
p.76
Gastric Secretions and Their Regulation
What is the role of pepsinogen in digestion?
Pepsinogen is converted to pepsin, an enzyme that breaks down proteins into peptides.
p.72
Gastric Motility and Emptying
How does hypertonic chyme influence gastric motility?
Hypertonic chyme slows down gastric motility.
p.84
Gastric Secretions and Their Regulation
What is the pH level in the neutralization zone of the gastric mucosal barrier?
The pH level in the neutralization zone is approximately 7.0.
p.18
Hormonal Regulation in the GI Tract
What triggers the release of Gastrin and where is it released from?
Gastrin is released by G-cells in the antrum of the stomach in response to stomach distention and neural (vagal) stimulation (GRP).
p.14
Nervous System Control of GI Functions
What role do sensory neurons in the submucosal plexus play?
They detect sensory information from the lumen of the gut.
p.16
Nervous System Control of GI Functions
What likely triggers the enterogastric reflex?
The presence of HCl in the duodenum, indicating a low pH in the stomach (< 1.5), likely triggers the enterogastric reflex.
p.88
Gastric Motility and Emptying
What happens to gastric pressure when a balloon is inflated in the stomach of a human volunteer?
Despite an increase in gastric volume by the inflation, gastric pressure remains relatively constant.
p.36
Components of the Gastrointestinal Tract
What ions are primarily added to the luminal solution during the production of saliva in the acinus?
Sodium (Na+), chloride (Cl-), potassium (K+), and bicarbonate (HCO3-).
p.19
Nervous System Control of GI Functions
What are the functions of enkephalins in the gastrointestinal system?
Enkephalins increase smooth muscle cell tone, mediate sphincter contraction, and delay transit time through the gut, making them useful in treating diarrhea.
p.45
Functions of the GI Tract
Where does the initial signal for muscle contraction originate?
Presynaptic nerve terminal.
p.66
Components of the Gastrointestinal Tract
What is the function of the lower esophageal sphincter (LES)?
The LES acts as a physiological sphincter, preventing the backflow of stomach contents into the esophagus.
p.88
Gastric Motility and Emptying
What effect would an adrenergic agonist have on gastric pressure?
An adrenergic agonist typically would not abolish the pressure-volume relationship in the stomach.
p.28
Nervous System Control of GI Functions
Which receptors are stimulated during mastication?
Oral and periodontal mechanoreceptors.
p.78
Gastric Secretions and Their Regulation
What is the role of anion exchange in the parietal cell during gastric acid secretion?
Anion exchange in the parietal cell helps to balance the charge by exchanging bicarbonate ions for chloride ions, which are then secreted into the stomach lumen.
p.30
Esophageal Motility and Peristalsis
What happens during the voluntary stage of the swallowing reflex?
A bolus of food is voluntarily pushed to the hard and soft palate.
p.75
Gastric Secretions and Their Regulation
What do surface mucosal cells secrete and where are they found?
Surface mucosal cells secrete mucus and alkaline secretion, and they are found throughout the entire mucosa of the stomach.
p.73
Gastric Motility and Emptying
What is the effect of prokinetic drugs like erythromycin on the small intestine?
They disrupt small intestine motility, which can cause nausea.
p.68
Components of the Gastrointestinal Tract
What is the significance of the pyloric sphincter in the stomach?
The pyloric sphincter regulates the passage of food from the stomach to the duodenum.
p.31
Nervous System Control of GI Functions
Which part of the nervous system controls the swallowing reflex?
The swallowing reflex is controlled by the central nervous system, specifically the brainstem.
p.31
Esophageal Motility and Peristalsis
What role does the epiglottis play in the swallowing reflex?
The epiglottis covers the trachea during swallowing to prevent food from entering the airway.
p.63
Esophageal Motility and Peristalsis
What type of pain is associated with Nutcracker Esophagus?
Nutcracker Esophagus is associated with angina-like pain.
p.69
Gastric Motility and Emptying
What factors inhibit gastric emptying?
Distention of the duodenum, presence of acid (secretin), fat (CCK), and carbohydrates (GIP), which are part of the Enterogastric Reflex.
p.22
Nervous System Control of GI Functions
What role do gap junctions play in the GI smooth muscle?
Gap junctions allow for the spread of electrical activity between smooth muscle cells, facilitating coordinated contractions.
p.60
Esophageal Motility and Peristalsis
What causes the relaxation of the LES during peristalsis?
The relaxation of the LES during peristalsis is related to the release of nitric oxide (NO) via nNOS (neuronal nitric oxide synthase) in the myenteric plexus.
p.84
Gastric Secretions and Their Regulation
What is the function of the gastric mucosal barrier?
The gastric mucosal barrier protects the stomach lining from the acidic environment of the stomach lumen.
p.12
Nervous System Control of GI Functions
What neurotransmitters are involved in excitatory signals in the GI tract?
Excitatory signals in the GI tract involve neurotransmitters such as acetylcholine (Ach) and kinins.
p.12
Nervous System Control of GI Functions
What are the two main muscle layers involved in GI movements?
The two main muscle layers involved in GI movements are the longitudinal muscle and the circular muscle.
p.84
Gastric Secretions and Their Regulation
What is the concentration of hydrogen ions ([H+]) in the neutralization zone?
The concentration of hydrogen ions ([H+]) in the neutralization zone is 100 μM.
p.39
Nervous System Control of GI Functions
How does the tonicity of salivary secretion change as secretion increases?
Tonicity increases but remains hypotonic to plasma.
p.10
Nervous System Control of GI Functions
What percentage of vagal fibers are sensory (afferent) and what percentage are efferent?
90% of vagal fibers are sensory (afferent) and 10% are efferent.
p.77
Gastric Secretions and Their Regulation
What role does water play in gastric secretions?
Water dissolves and dilutes ingested foods.
p.47
Components of the Gastrointestinal Tract
How are the thick and thin filaments in smooth muscle cells organized?
Smooth muscle cells have thick and thin filaments, but they are not organized into striations.
p.31
Esophageal Motility and Peristalsis
What happens during the oral phase of swallowing?
During the oral phase, the tongue pushes the food bolus to the back of the mouth, triggering the swallowing reflex.
p.88
Hormonal Regulation in the GI Tract
What is the role of CCK (cholecystokinin) in gastric function?
CCK primarily stimulates the digestion of fat and protein and has a minor role in gastric motility.
p.88
Hormonal Regulation in the GI Tract
What is the function of gastrin in the gastrointestinal tract?
Gastrin stimulates the secretion of gastric acid, which aids in digestion.
p.4
Gastroesophageal Reflux Disease (GERD)
What are the common symptoms of GERD?
Common symptoms include heartburn, regurgitation of food or sour liquid, and difficulty swallowing.
p.4
Gastroesophageal Reflux Disease (GERD)
What can frequent acid reflux lead to in GERD patients?
Frequent acid reflux can lead to inflammation of the esophagus, known as esophagitis.
p.69
Gastric Motility and Emptying
How is the rate of gastric emptying regulated?
By neural and hormonal signals from the stomach and duodenum, with inhibition always prevailing.
p.76
Components of the Gastrointestinal Tract
What are the main regions of the stomach?
Pylorus, Cardia, Fundus, Corpus, Antrum.
p.76
Gastric Secretions and Their Regulation
What is the function of G cells in the pyloric glands?
G cells secrete gastrin, which stimulates acid secretion by the stomach.
p.6
Nervous System Control of GI Functions
What effect does the parasympathetic nervous system have on the GI tract?
The parasympathetic nervous system generally stimulates digestive activities, increasing motility and secretion.
p.37
Components of the Gastrointestinal Tract
Is water permeable across ductal cells?
No, water is impermeable across ductal cells.
p.60
Esophageal Motility and Peristalsis
What is the relationship between neural activity and the opening of the LES?
The opening of the LES is due to neural activity, specifically the release of nitric oxide (NO).
p.76
Gastric Secretions and Their Regulation
What type of mucosa is responsible for acid secretion in the stomach?
Acid (Oxyntic) Secreting Mucosa.
p.72
Gastric Motility and Emptying
What is the enterogastric reflex and its effect on gastric motility?
The enterogastric reflex is a feedback mechanism that slows down gastric motility in response to duodenal distension and other factors.
p.39
Nervous System Control of GI Functions
What is the effect of sympathetic stimulation on salivary secretion?
It produces a small, short-lived increase in secretion due to beta-adrenergic stimulation.
p.84
Gastric Secretions and Their Regulation
What is the concentration of bicarbonate ions (HCO3-) in the stomach lumen?
The concentration of bicarbonate ions (HCO3-) in the stomach lumen is 0 mM.
p.18
Hormonal Regulation in the GI Tract
What are the primary functions of Gastrin?
Gastrin stimulates the parietal cells in the body of the stomach to secrete HCL, stimulates gastric motility, and has structural similarities to CCK, stimulating the gallbladder and pancreas to secrete.
p.14
Nervous System Control of GI Functions
Which types of neurons are found in the submucosal plexus?
Sensory neurons, interneurons, and secretomotor neurons.
p.86
Pathophysiology of GI Disorders
How does ammonia produced by H. pylori bacteria affect the stomach environment?
Ammonia helps buffer the acid in the stomach.
p.14
Nervous System Control of GI Functions
What is the role of mechanoreceptors in the submucosal plexus?
They detect mechanical changes such as stretching in the gut wall.
p.35
Components of the Gastrointestinal Tract
What are the components of primary secretion in the salivon?
Enzymes, mucus, and extracellular fluid.
p.36
Components of the Gastrointestinal Tract
Which ions move into the lumen during saliva production?
Chloride (Cl-), bicarbonate (HCO3-), and potassium (K+).
p.67
Esophageal Motility and Peristalsis
What are slow waves in the context of GI smooth muscle activity?
Slow waves are rhythmic fluctuations in membrane potential that occur at a frequency of 3 per minute in the stomach.
p.73
Gastric Motility and Emptying
What effect does feeding have on the Migrating Motor Complex?
Feeding inhibits the Migrating Motor Complex.
p.17
Hormonal Regulation in the GI Tract
What does 'AP' stand for in the context of hormonal regulation?
'AP' stands for anterior pituitary, which is a gland that releases various hormones regulating different bodily functions.
p.47
Components of the Gastrointestinal Tract
Do smooth muscle cells need innervation for contractions to occur?
No, smooth muscle cells do not need innervation for contractions to occur; they can contract in response to stretch.
p.80
Hormonal Regulation in the GI Tract
What is the effect of secretin on acid secretion?
Secretin has mild effects on turning off acid secretion.
p.6
Nervous System Control of GI Functions
What are the two main components of the nervous system that innervate the gastrointestinal (GI) tract?
The enteric nervous system (ENS) and the autonomic nervous system (ANS).
p.30
Esophageal Motility and Peristalsis
What happens to the lower esophageal sphincter (LES) as the peristaltic wave moves towards the stomach?
There is a reflex opening of the LES.
p.37
Components of the Gastrointestinal Tract
How is potassium secreted in the ductal cells?
Potassium is secreted by H+/K+ exchange (active).
p.27
Gastroesophageal Reflux Disease (GERD)
How might the patient's nightly consumption of Pepsi and chocolate affect her condition?
Both Pepsi and chocolate can relax the lower esophageal sphincter and increase acid production, worsening GERD symptoms.
p.37
Components of the Gastrointestinal Tract
What drives the secretion of ions in the ductal cells?
Secretion is driven by Ca++ dependent signaling, which opens Cl- channels.
p.72
Gastric Motility and Emptying
What is the effect of H+ (acid) on gastric motility?
High levels of H+ (acid) slow down gastric motility.
p.6
Nervous System Control of GI Functions
What is the function of the submucosal plexus in the GI tract?
The submucosal plexus primarily regulates enzyme secretion, blood flow, and ion and water transport.
p.72
Nervous System Control of GI Functions
What is the dominant effect of the vagovagal reflex on the stomach?
The vagovagal reflex primarily slows down the stomach's motility.
p.18
Hormonal Regulation in the GI Tract
What receptors does Cholecystokinin (CCK) have an affinity for?
CCK has a high affinity for CCK A receptors and a low affinity for CCK B receptors.
p.24
Immune Function in the GI Tract
What is the significance of the lamina propria in the GI tract's immune function?
The lamina propria contains a variety of immune cells, including macrophages and plasma cells, that help in immune responses.
p.39
Nervous System Control of GI Functions
What happens to sodium and chloride concentration during maximal salivation?
Their concentration increases because there is less time for ductal cells to reabsorb them.
p.16
Nervous System Control of GI Functions
What is the gastrocolic reflex and how is it mediated?
The gastrocolic reflex involves information carried from chemo- or mechano-receptors in the gut to the spinal cord/brainstem and then back to the gut. It is mediated by the release of gastrin, CCK, PGE2, serotonin, and motilin.
p.10
Nervous System Control of GI Functions
Where do the pelvic nerves (pudendal nerve) originate in the sacral division of the parasympathetic system?
In the 2nd, 3rd, and 4th sacral segments of the spinal cord.
p.14
Nervous System Control of GI Functions
What are the two main types of cells regulated by the submucosal plexus?
Absorptive cells and crypt cells (secretory cells).
p.69
Gastric Motility and Emptying
What is the vagovagal reflex in the context of gastric motility?
It allows the stomach to increase in size without increasing pressure, enhancing compliance.
p.17
Hormonal Regulation in the GI Tract
What is neurocrine signaling?
Neurocrine signaling involves the release of hormones or neurotransmitters from nerve cells that affect other cells, often at a synapse.
p.47
Components of the Gastrointestinal Tract
What are the two types of smooth muscle units?
Smooth muscle can be multiunit (individual motor units) or unitary (syncytium).
p.4
Gastroesophageal Reflux Disease (GERD)
What is GERD?
GERD stands for Gastroesophageal Reflux Disease, a chronic condition where stomach acid frequently flows back into the esophagus.
p.34
Functions of the GI Tract
How does saliva contribute to taste?
Saliva acts as a solvent, allowing taste buds to detect flavors.
p.30
Esophageal Motility and Peristalsis
What mechanisms close off the trachea during swallowing?
The vestibular and vocal folds expand to close the larynx, and the epiglottis closes off the trachea.
p.11
Nervous System Control of GI Functions
Which neurotransmitters are considered excitatory in the Enteric Nervous System?
Acetylcholine (Ach) and kinins (substance P, 5-HT).
p.37
Components of the Gastrointestinal Tract
What ions are present in higher concentrations in saliva compared to plasma?
Bicarbonate and potassium.
p.27
Gastroesophageal Reflux Disease (GERD)
What dietary habits does the patient report that may be contributing to her condition?
Consuming a nightly can of Pepsi and a dark chocolate Milky Way bar.
p.4
Gastroesophageal Reflux Disease (GERD)
What is esophageal stricture and how is it related to GERD?
Esophageal stricture is the narrowing of the esophagus due to scar tissue from acid damage, which can result from chronic GERD.
p.60
Esophageal Motility and Peristalsis
What is the LES and what is its primary characteristic?
The LES (Lower Esophageal Sphincter) is an area of tonic contraction of the esophagus, characterized by high pressure.
p.22
Nervous System Control of GI Functions
What are spike potentials and what triggers them?
Spike potentials are true action potentials in the GI smooth muscle, triggered by factors such as stretch and parasympathetic stimulation (acetylcholine).
p.6
Nervous System Control of GI Functions
What is the function of the myenteric plexus in the GI tract?
The myenteric plexus primarily controls GI tract motility.
p.24
Immune Function in the GI Tract
What types of cells are involved in the immune function of the GI tract?
B cells, T cells, intraepithelial lymphocytes, mucosal mast cells, plasma cells, macrophages.
p.24
Immune Function in the GI Tract
What is the function of the follicle-associated epithelium in the GI tract?
It contains specialized cells that facilitate the transport of antigens to immune cells.
p.18
Hormonal Regulation in the GI Tract
What are the primary functions of Secretin?
Secretin stimulates the secretion of bicarbonate (HCO3-) from the liver and pancreatic ductal cells and acts as an enterogastrone.
p.24
Immune Function in the GI Tract
What is the role of antibodies in the immune function of the GI tract?
Antibodies neutralize pathogens and toxins, preventing them from causing infections.
p.84
Gastric Secretions and Their Regulation
What cells produce the mucus that forms part of the gastric mucosal barrier?
Mucus cells produce the mucus that forms part of the gastric mucosal barrier.
p.85
Gastric Motility and Emptying
What is the function of Bethanechol in gastric motility?
Bethanechol is a muscarinic agonist that stimulates gastric smooth muscle contraction.
p.85
Gastric Motility and Emptying
How does dopamine affect cholinergic activity in the gastrointestinal tract?
Dopamine blocks cholinergic activity, which can inhibit gastric motility.
p.35
Components of the Gastrointestinal Tract
What role do ductal cells play in saliva modification?
Ductal cells modify saliva, making it hypotonic to plasma.
p.27
Gastroesophageal Reflux Disease (GERD)
What are the patient's physical characteristics and BMI range?
She is 5 ft 3 inches tall, weighs 165 pounds, and her BMI is calculated to be 25.0 - 29.9.
p.63
Esophageal Motility and Peristalsis
What are the treatment options for Nutcracker Esophagus?
Treatment options for Nutcracker Esophagus include calcium channel blockers, nitroglycerin, and botox.
p.69
Gastric Motility and Emptying
What factors increase gastric motility?
Distention of the stomach and the hormone gastrin.
p.34
Functions of the GI Tract
What are the inorganic components of saliva?
Ions such as sodium, chloride, bicarbonate, calcium, and potassium.
p.34
Functions of the GI Tract
What are the organic components and enzymes found in saliva?
Mucin, amylase, lipase, Epidermal Growth Factor (EGF), and blood group antigens.
p.22
Nervous System Control of GI Functions
What is the concept of a syncytium in the context of GI smooth muscle?
A syncytium refers to the network of interconnected smooth muscle cells that function as a single unit, allowing for coordinated contractions.
p.22
Nervous System Control of GI Functions
How do sympathetic nerves affect GI motility?
Sympathetic nerves, through the release of norepinephrine (NE), inhibit GI motility by decreasing the frequency of spike potentials.
p.37
Nervous System Control of GI Functions
What type of stimulation affects salivary secretion and how?
Parasympathetic stimulation affects salivary secretion, making it hypotonic.
p.24
Immune Function in the GI Tract
What are Peyer's patches and where are they located?
Peyer's patches are small masses of lymphatic tissue found in the small intestine, important for immune surveillance.
p.18
Hormonal Regulation in the GI Tract
What stimulates the release of Secretin and where is it released from?
Secretin is released by S cells of the duodenum in response to acid (H+) and fats.
p.85
Gastric Motility and Emptying
What can cause damage to gastric smooth muscle or its innervation?
Damage can be caused by conditions such as diabetes or damage to the vagus nerve.
p.14
Nervous System Control of GI Functions
What is the primary function of the submucosal plexus (Meissner's plexus) in the gastrointestinal tract?
The submucosal plexus primarily regulates GI secretions and blood flow.
p.16
Nervous System Control of GI Functions
What triggers the gastrocolic reflex and in which population is it pronounced?
The gastrocolic reflex is triggered by the ingestion of a meal and is pronounced in infants.
p.14
Nervous System Control of GI Functions
What is the function of secretomotor neurons in the submucosal plexus?
They stimulate secretory cells in the epithelium to release digestive enzymes and fluids.
p.86
Pathophysiology of GI Disorders
Which common pain reliever does not increase the risk of ulcers by inhibiting prostaglandin production?
Acetaminophen (Tylenol, paracetamol).
p.48
Esophageal Motility and Peristalsis
What type of muscle event is primarily involved in GI tract movements?
Mostly a circular muscle event.
p.48
Esophageal Motility and Peristalsis
What role does longitudinal muscle play in peristalsis?
It shortens the distance between points but does not play a significant role in peristalsis.
p.4
Gastroesophageal Reflux Disease (GERD)
Can GERD lead to dental problems?
Yes, GERD can lead to dental erosion and other oral health issues due to the acid affecting the teeth.
p.76
Gastric Secretions and Their Regulation
What do oxyntic (parietal) cells secrete?
Oxyntic (parietal) cells secrete hydrochloric acid (HCL) and intrinsic factor.
p.22
Nervous System Control of GI Functions
How do parasympathetic nerves affect GI motility?
Parasympathetic nerves, through the release of acetylcholine (Ach), stimulate GI motility by increasing the frequency of spike potentials.
p.12
Nervous System Control of GI Functions
What is the role of the submucosal plexus (Meissner’s plexus)?
The submucosal plexus (Meissner’s plexus) primarily regulates enzyme secretion, blood flow, and ion and water transport in the gastrointestinal tract.
p.18
Hormonal Regulation in the GI Tract
What triggers the release of Cholecystokinin (CCK) and where is it released from?
CCK is released by intestinal mucosal cells (I cells) from the duodenum to the ileum in response to fats.
p.24
Immune Function in the GI Tract
What is the role of M cells in the immune function of the GI tract?
M cells transport antigens from the gut lumen to immune cells in Peyer's patches.
p.10
Nervous System Control of GI Functions
What effect does stimulation of the vagus nerve have on the gut?
It causes an increase in motility and secretions.
p.86
Pathophysiology of GI Disorders
What are the primary causes of gastric and duodenal ulcers?
Loss of gastric barrier, increased acid secretion, and bacterial infection (H. pylori).
p.85
Gastric Motility and Emptying
What is the role of Cisapride in treating gastroparesis?
Cisapride is a 5HT4 receptor agonist that enhances gastric motility.
p.14
Nervous System Control of GI Functions
What neurotransmitters are associated with the submucosal plexus?
Acetylcholine (Ach) and Vasoactive Intestinal Peptide (VIP).
p.16
Nervous System Control of GI Functions
What is the colonoileal reflex and what does it inhibit?
The colonoileal reflex involves signals from the colon to the ileum to inhibit the contents at the ileocecal valve from emptying into the colon.
p.35
Components of the Gastrointestinal Tract
Why is saliva hypotonic to plasma?
Because ductal cells are impermeable to water reabsorption.
p.76
Gastric Secretions and Their Regulation
What is the function of intrinsic factor secreted by oxyntic cells?
Intrinsic factor is essential for the absorption of vitamin B12 in the small intestine.
p.6
Nervous System Control of GI Functions
What are the two main plexuses of the enteric nervous system?
The myenteric plexus (Auerbach's plexus) and the submucosal plexus (Meissner's plexus).
p.24
Immune Function in the GI Tract
What does GALT stand for in the context of immune function in the GI tract?
Gut-Associated Lymphoid Tissue.
p.24
Immune Function in the GI Tract
What is the role of intraepithelial lymphocytes in the GI tract?
They are involved in the immune response by providing a first line of defense against pathogens.
p.84
Gastric Secretions and Their Regulation
What is the concentration of hydrogen ions ([H+]) in the stomach lumen?
The concentration of hydrogen ions ([H+]) in the stomach lumen is 20 mM.
p.24
Immune Function in the GI Tract
What are the afferent and efferent limbs in the context of immune function in the GI tract?
The afferent limb refers to the pathway that brings antigens to immune cells, while the efferent limb refers to the pathway that carries immune responses away from the site of antigen entry.
p.85
Gastric Motility and Emptying
What is gastroparesis?
Gastroparesis is a condition characterized by delayed gastric emptying without any mechanical obstruction.
p.85
Gastric Motility and Emptying
How does Erythromycin help in treating gastroparesis?
Erythromycin acts as a motilin agonist, which stimulates gastric motility.
p.86
Pathophysiology of GI Disorders
Why is it beneficial to inhibit acid production when treating H. pylori infections?
Inhibiting acid makes the bacteria more susceptible to antibiotics.
p.16
Nervous System Control of GI Functions
What triggers the defecation reflex and what are its components?
The defecation reflex is triggered by rectal distention (intrinsic component) and involves signals from the spinal cord (extrinsic component).
p.72
Gastric Motility and Emptying
How does lipid content in the stomach affect gastric motility?
High lipid content slows down gastric motility.
p.39
Nervous System Control of GI Functions
What effect does damage to the parasympathetic nerves have on salivary glands?
It causes atrophy of the gland.
p.12
Nervous System Control of GI Functions
What neurotransmitters are involved in inhibitory signals in the GI tract?
Inhibitory signals in the GI tract involve neurotransmitters such as vasoactive intestinal peptide (VIP), norepinephrine (NE), and nitric oxide.
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Nervous System Control of GI Functions
What is the role of pacemaker cells in the GI tract?
Pacemaker cells, also known as interstitial cells of Cajal (ICC), generate rhythmic electrical impulses that coordinate smooth muscle contractions in the gastrointestinal tract.
p.39
Nervous System Control of GI Functions
Why are the secretions from sympathetic stimulation short-lived?
Because of a decrease in blood flow.
p.85
Gastric Motility and Emptying
What is delayed gastric emptying?
Delayed gastric emptying is a condition where the stomach takes too long to empty its contents into the small intestine.
p.84
Gastric Secretions and Their Regulation
What is the role of the bicarbonate-rich zone in the gastric mucosal barrier?
The bicarbonate-rich zone neutralizes stomach acid (HCl) to form water (H2O) and carbon dioxide (CO2).
p.18
Hormonal Regulation in the GI Tract
What receptors does Gastrin have an affinity for?
Gastrin has a high affinity for CCK B receptors.
p.18
Hormonal Regulation in the GI Tract
What is the primary function of Motilin?
Motilin is involved in the migrating motor complex.
p.10
Nervous System Control of GI Functions
What is the function of the pelvic nerves in the sacral division?
They function in the defecation reflex.
p.22
Nervous System Control of GI Functions
What is the significance of slow waves in the GI tract?
Slow waves set the basic rhythm of electrical activity in the GI smooth muscle, controlling the timing of spike potentials and thus muscle contractions.
p.85
Gastric Motility and Emptying
How can delayed gastric emptying be treated?
It can be treated with prokinetic drugs that stimulate muscle activity through cholinergic stimulation.
p.39
Nervous System Control of GI Functions
What happens to bicarbonate during salivation?
Bicarbonate is selectively secreted, making the saliva more alkaline.
p.16
Nervous System Control of GI Functions
What is the gastroileal reflex and what does it stimulate?
The gastroileal reflex is stimulated by food in the stomach and leads to the opening of the ileocecal valve.
p.86
Pathophysiology of GI Disorders
Which group of patients is at risk for ulcers due to chronic use of NSAIDs?
Patients with rheumatoid arthritis who take NSAIDs on a chronic basis.
p.35
Components of the Gastrointestinal Tract
What is the nature of primary secretion in the acinus?
Primary secretion is isotonic to plasma.
p.18
Hormonal Regulation in the GI Tract
What are the primary functions of Cholecystokinin (CCK)?
CCK causes contraction of the gallbladder, relaxation of the sphincter of Oddi to release bile into the small intestine, acts as a pancreozymin, and functions as an enterogastrone to decrease gastric secretions and motility.
p.39
Nervous System Control of GI Functions
What is the characteristic of primary salivary secretion?
It is isotonic to plasma.
p.39
Nervous System Control of GI Functions
How does potassium concentration change during salivation?
Potassium concentration remains relatively constant.
p.18
Hormonal Regulation in the GI Tract
What triggers the release of Motilin and where is it released from?
Motilin is released by M cells of the intestinal (duodenal) mucosa.
p.16
Nervous System Control of GI Functions
What is the enterogastric reflex and what does it inhibit?
The enterogastric reflex involves signals from the small intestine to the stomach to inhibit gastric motility and secretions. It also shuts off the release of gastrin.
p.16
Nervous System Control of GI Functions
What is the vomiting reflex and where are the signals sent?
The vomiting reflex involves signals to and from the vomiting center in the brainstem.
p.35
Components of the Gastrointestinal Tract
How is chloride (Cl) modified in saliva?
Chloride (Cl) is passively absorbed.
p.35
Components of the Gastrointestinal Tract
What types of cells are involved in the structure of a salivon?
Acinar cells, myoepithelial cells, and ductal cells.
p.10
Nervous System Control of GI Functions
What is the vagovagal reflex?
A reflex where the vagus nerve transmits information from the gut to the brain and back.
p.85
Gastric Motility and Emptying
How do Neostigmine, Eserine, and Edrophonium aid in treating delayed gastric emptying?
These drugs inhibit cholinesterase, thereby increasing cholinergic activity and enhancing gastric motility.
p.14
Nervous System Control of GI Functions
What is the relationship between the submucosal plexus and the myenteric plexus?
The submucosal plexus primarily controls secretions and blood flow, while the myenteric plexus (Auerbach's plexus) primarily controls gut motility.
p.35
Components of the Gastrointestinal Tract
How is potassium (K) modified in saliva?
Potassium (K) is actively secreted.
p.86
Pathophysiology of GI Disorders
Why do H. pylori bacteria flourish in the stomach?
They flourish in an acidic environment.
p.10
Nervous System Control of GI Functions
Which regions of the gut are innervated by the pelvic nerves in the sacral division?
The descending colon, sigmoid colon, rectum, and anal regions.
p.86
Pathophysiology of GI Disorders
How do NSAIDs like aspirin or ibuprofen contribute to ulcer formation?
NSAIDs inhibit prostaglandin production, which can increase gastric acid production.
p.35
Components of the Gastrointestinal Tract
How is sodium (Na) modified in saliva?
Sodium (Na) is actively absorbed.
p.35
Components of the Gastrointestinal Tract
How is bicarbonate (HCO3) modified in saliva?
Bicarbonate (HCO3) is passively secreted.
p.86
Pathophysiology of GI Disorders
What enzyme do H. pylori bacteria contain and what is its function?
H. pylori bacteria contain urease, which converts urea to ammonia (toxic to epithelial cells) and CO2.
p.85
Gastric Motility and Emptying
What is the mechanism of action of Metoclopramide in treating gastroparesis?
Metoclopramide is a dopamine D2 antagonist that enhances cholinergic activity and promotes gastric motility.
p.16
Pathophysiology of GI Disorders
Which GI reflex is implicated in the pathogenesis of IBS?
The gastrocolic reflex is implicated in the pathogenesis of IBS.
p.14
Nervous System Control of GI Functions
What is the constant state of agitation in the submucosal plexus referring to?
It refers to the continuous activity of neurons regulating GI secretions and blood flow.
