p.1
Functions of the Digestive System
What is the primary function of the digestive system?
To break down food into forms that can be absorbed and used by body cells.
p.1
Functions of the Digestive System
What additional substances does the digestive system absorb?
Water, vitamins, and minerals.
p.6
Functions of the Digestive System
What role does water play in saliva?
It dissolves food and helps produce taste to initiate digestion.
p.5
Anatomy and Functions of the Mouth
Where are the submandibular glands found?
In the floor of the mouth, below the lower jaw.
p.1
Overview of the Digestive System
What is the structure of the digestive system?
A tubular system that extends from the mouth to the anus.
p.6
Functions of the Digestive System
How do chloride ions in saliva contribute to digestion?
They activate salivary amylase, which starts the breakdown of starch.
p.6
Functions of the Digestive System
What role does immunoglobulin A (IgA) play in saliva?
It prevents microbes from entering or attaching to epithelial cells.
p.5
Anatomy and Functions of the Mouth
What are some locations of minor salivary glands?
In the cheeks, palates, tongue, and lips.
p.2
Functions of the Digestive System
What is defecation?
The process of eliminating wastes, indigestible substances, and digested materials that were not absorbed through the anus.
p.10
Layers of the Gastrointestinal Tract
What types of muscle make up the upper and lower esophageal sphincters?
The upper esophageal sphincter consists of skeletal muscle, while the lower esophageal sphincter consists of smooth muscle.
p.6
Functions of the Digestive System
What is the main composition of saliva?
99.5% water and 0.5% solutes.
p.3
Layers of the Gastrointestinal Tract
What is the purpose of the muscularis mucosae?
Increases the surface area of the stomach and small intestine to enhance digestion and absorption.
p.5
Anatomy and Functions of the Mouth
What is the location of the sublingual glands?
Beneath the tongue and superior to the submandibular glands.
p.4
Layers of the Gastrointestinal Tract
What is the serosa?
A protective and connective tissue that forms the outer layer of the gastrointestinal tract.
p.2
Functions of the Digestive System
What is the process of ingestion?
Taking foods and liquids into the mouth.
p.2
Functions of the Digestive System
What is motility in the context of the digestive system?
The capability of the GI tract to mix and move material along its length through alternating contractions and relaxations of smooth muscle.
p.7
Anatomy and Functions of the Mouth
What are the two types of muscles in the tongue?
Extrinsic muscles and intrinsic muscles.
p.7
Anatomy and Functions of the Mouth
What do lingual glands secrete?
Mucus and fluid containing the enzyme lingual lipase.
p.8
Anatomy and Functions of the Mouth
What do root canals contain?
Blood vessels, nerves, and lymphatic vessels.
p.9
Anatomy and Functions of the Mouth
What is the role of saliva in digestion?
It dissolves small food molecules and contains enzymes.
p.10
Digestive Processes in the Stomach
What is peristalsis?
A progression of coordinated contractions and relaxations of the muscularis that pushes the bolus toward the stomach.
p.6
Functions of the Digestive System
What is the function of mucus in saliva?
It lubricates and moistens food for easy swallowing.
p.6
Anatomy and Functions of the Mouth
What is the composition and function of the tongue?
The tongue is composed of skeletal muscle covered with mucous membrane; it helps taste, swallow food, and speak.
p.4
Anatomy and Functions of the Mouth
What is the hard palate made up of?
Palatine and maxillae bones covered with mucous membrane.
p.12
Digestive Processes in the Stomach
Why is intrinsic factor important?
It is needed for the absorption of vitamin B12.
p.14
Digestive Processes in the Stomach
What protects the stomach epithelial cells from gastric juices?
A 1-3 mm thick layer of alkaline mucus.
p.15
Digestive Processes in the Stomach
What role does carbonic anhydrase play in parietal cells?
It produces carbonic acid from CO2 and H2O, which dissociates into H+ and HCO3-.
p.18
Pancreas and Its Role in Digestion
What is pancreatic juice composed of?
Water, salts, sodium bicarbonate, and several enzymes.
p.18
Liver and Gallbladder Functions
How is the liver anatomically divided?
Into two lobes: the right lobe (larger) and the left lobe (smaller), separated by the falciform ligament.
p.19
Gallbladder Functions
What is the primary function of the gall bladder?
To store and concentrate bile.
p.20
Liver and Gallbladder Functions
What is the role of bile salts in digestion?
They aid in emulsification and absorption of lipids.
What do chemoreceptors in the stomach monitor?
The pH of the stomach chyme.
p.3
Layers of the Gastrointestinal Tract
What are the four layers of the GI tract wall?
Mucosa, submucosa, muscularis, and serosa.
p.3
Layers of the Gastrointestinal Tract
What does the submucosa contain that is important for nutrient absorption?
Many blood and lymphatic vessels.
p.5
Anatomy and Functions of the Mouth
Where do the ducts of the submandibular glands open?
Into the oral cavity lateral to the lingual frenulum.
p.2
Gastrointestinal Tract and Accessory Organs
What role do accessory digestive organs play?
They assist in digestion but do not come into direct contact with food; they produce secretions that aid in chemical breakdown.
p.7
Anatomy and Functions of the Mouth
What are papillae on the tongue?
Structures that cover the upper and lateral surfaces of the tongue, many of which contain taste buds.
p.10
Functions of the Digestive System
What regulates the movement of food from the pharynx into the esophagus?
The upper esophageal sphincter (UES).
p.16
Pancreas and Its Role in Digestion
What is the tail of the pancreas?
The last tapering portion of the pancreas.
p.18
Pancreas and Its Role in Digestion
What is the function of pancreatic amylase?
It is a starch-digesting enzyme.
p.20
Liver and Gallbladder Functions
What are the main components of bile?
Water, bile salts, cholesterol, lecithin, bile pigments, and several ions.
p.21
Small Intestine: Structure and Function
What is the function of the small intestine?
It plays a major role in digestion and absorption of nutrients.
p.23
Mucosa of the Small Intestine
What are circular folds in the small intestine?
Folds of mucosa and submucosa that increase surface area and facilitate the movement of chime.
p.24
Layers of the Gastrointestinal Tract
What does the submucosa of the duodenum secrete?
Alkaline mucus that helps neutralize gastric acid in the chyme.
p.27
Functions of the Digestive System
Which vitamins are absorbed by simple diffusion?
Water-soluble vitamins B and C.
p.3
Layers of the Gastrointestinal Tract
What role does the epithelium play in the GI tract?
Protection, secretion, and absorption.
p.3
Layers of the Gastrointestinal Tract
What type of tissue binds the mucosa to the muscularis in the submucosa?
Areolar connective tissue.
p.6
Functions of the Digestive System
What is the function of lysozyme in saliva?
It destroys harmful bacteria.
p.4
Layers of the Gastrointestinal Tract
What is the peritoneum?
The largest serous membrane in the body.
p.2
Digestive Processes in the Stomach
How does mechanical digestion occur?
Through the cutting and grinding of food by teeth and the mixing by smooth muscles in the stomach and small intestine.
p.10
Functions of the Digestive System
What facilitates the act of swallowing?
The secretion of saliva and mucus.
p.9
Digestive Processes in the Stomach
In what environment is lingual lipase activated?
In the acidic environment of the stomach.
p.17
Pancreas and Its Role in Digestion
What do exocrine cells in the pancreas secrete?
Pancreatic juice, a mixture of fluid and digestive enzymes.
p.18
Pancreas and Its Role in Digestion
Which enzymes in pancreatic juice are responsible for protein digestion?
Trypsin, Chymotrypsin, Carboxypeptidase, and Elastase.
p.19
Gallbladder Functions
How does the gall bladder concentrate bile?
By the absorption of water and ions.
p.20
Liver and Gallbladder Functions
How does the liver maintain normal blood glucose levels?
By breaking down glycogen to glucose and converting lactic acid and amino acids into glucose.
p.21
Liver and Gallbladder Functions
What is the role of the liver in vitamin D synthesis?
The liver, along with skin and kidneys, participates in synthesizing the active form of vitamin D.
p.21
Small Intestine: Structure and Function
Where does the small intestine begin?
At the pyloric sphincter of the stomach.
p.23
Mucosa of the Small Intestine
What are villi and their function?
Fingerlike projections of mucosa that vastly increase surface area for absorption and digestion.
p.3
Layers of the Gastrointestinal Tract
What are the three layers of the mucosa?
Epithelium, lamina propria, and muscularis mucosae.
p.4
Layers of the Gastrointestinal Tract
What types of muscles are found in the muscularis layer of the gastrointestinal tract?
Both skeletal muscles and smooth muscles.
p.2
Digestive Processes in the Stomach
What are the two types of digestion?
Mechanical digestion and chemical digestion.
p.12
Digestive Processes in the Stomach
What substances do chief cells secrete?
Pepsinogen and gastric lipase.
p.9
Digestive Processes in the Stomach
What does salivary amylase convert starch into?
Monosaccharides and disaccharides.
p.11
Anatomy and Functions of the Mouth
What are the four main regions of the stomach?
Cardia, fundus, body, and pylorus.
p.11
Layers of the Gastrointestinal Tract
What are rugae in the stomach?
Large folds in the mucosa that can be seen with the unaided eye when the stomach is empty.
p.13
Layers of the Gastrointestinal Tract
What type of tissue makes up the submucosa?
Areolar connective tissue.
p.15
Digestive Processes in the Stomach
What stimulates HCl secretion in parietal cells?
Gastrin, Acetylcholine, and Histamine.
p.15
Gastrointestinal Tract and Accessory Organs
Where is the head of the pancreas located?
Near the curve of the duodenum.
p.18
Liver and Gallbladder Functions
What are the three portions of the gallbladder?
Fundus (inferior broad portion), body (middle portion), and neck (upper taper portion).
p.21
Small Intestine: Structure and Function
What are the three major parts of the small intestine?
Duodenum, jejunum, and ileum.
p.24
Layers of the Gastrointestinal Tract
What surrounds the small intestine?
The serosa (or visceral peritoneum).
p.5
Functions of the Digestive System
What is saliva's role in the mouth?
To keep mucous membranes moist, cleanse the mouth and teeth, lubricate, dissolve, and begin the chemical breakdown of food.
p.6
Functions of the Digestive System
What is the pH range of saliva, and why is it important?
6.35 - 6.85; phosphate and bicarbonate ions buffer acidic food.
p.4
Layers of the Gastrointestinal Tract
What is the myenteric plexus?
A bundle of neurons present in the muscularis layer.
p.2
Functions of the Digestive System
What is absorption in the digestive system?
The entrance of ingested and secreted fluids, ions, and products of digestion into the epithelial cells lining the GI tract.
p.8
Anatomy and Functions of the Mouth
What does enamel primarily consist of?
Calcium phosphate and calcium carbonate.
p.7
Anatomy and Functions of the Mouth
What is the function of teeth in the digestive system?
To cut, tear, and pulverize solid food into smaller particles for easier swallowing and digestion.
p.11
Functions of the Digestive System
What is the primary function of the esophagus?
To secrete mucus and transport food into the stomach.
p.14
Digestive Processes in the Stomach
How is pepsin kept from digesting the proteins in stomach cells?
It is secreted in an inactive form called pepsinogen.
p.16
Pancreas and Its Role in Digestion
What is the function of the pancreatic duct?
It carries pancreatic juices into the duodenum and combines with the common bile duct to form the hepatopancreatic ampulla.
p.15
Gastrointestinal Tract and Accessory Organs
What is the anatomical position of the pancreas?
It is a retroperitoneal gland located posterior to the greater curvature of the stomach.
p.18
Liver and Gallbladder Functions
What is the location of the liver in the body?
Inferior to the diaphragm.
p.19
Anatomy and Functions of the Mouth
What is the pathway of bile from hepatocytes to the common bile duct?
Bile canaliculi → bile ductules → left/right hepatic ducts → common hepatic duct → cystic duct → common bile duct.
p.20
Liver and Gallbladder Functions
What happens to excess glucose when blood sugar levels rise?
It is converted into glycogen and triglycerides for storage.
p.23
Mucosa of the Small Intestine
What is the function of absorptive cells in the small intestine?
They digest and absorb nutrients.
p.3
Layers of the Gastrointestinal Tract
What is the function of the lamina propria?
Contains blood and lymphatic vessels that transfer absorbed nutrients and contains immune system cells.
p.4
Layers of the Gastrointestinal Tract
What is the submucosal plexus?
An extensive network of neurons that is part of the enteric nervous system (ENS).
p.4
Layers of the Gastrointestinal Tract
What are the two divisions of the peritoneum?
Parietal peritoneum and visceral peritoneum.
p.7
Anatomy and Functions of the Mouth
What is the role of intrinsic muscles of the tongue?
They alter the shape and size of the tongue for speech and swallowing.
p.10
Gastrointestinal Tract and Accessory Organs
Where does the esophagus start and end?
Starts from the inferior end of the laryngopharynx and ends at the superior portion of the stomach.
p.11
Functions of the Digestive System
Does the esophagus produce digestive enzymes?
No, it does not produce digestive enzymes.
p.16
Pancreas and Its Role in Digestion
What is the hepatopancreatic ampulla?
It is formed by the combination of the pancreatic duct and the common bile duct, opening into the duodenum.
p.19
Gallbladder Functions
What triggers the ejection of bile from the gall bladder?
Contraction of smooth muscles.
p.20
Liver and Gallbladder Functions
What is the function of hepatocytes in lipid metabolism?
They store triglycerides, break down fatty acids for ATP, synthesize lipoproteins, and produce bile salts from cholesterol.
p.23
Mucosa of the Small Intestine
What types of cells are found in the mucosa of the small intestine?
Absorptive cells, Goblet cells, Paneth cells, and Endocrine cells.
p.24
Functions of the Digestive System
What types of nucleotide-digesting enzymes are present in brush border enzymes?
Nucleosidases and phosphatases.
p.28
Anatomy and Functions of the Mouth
What is attached to the cecum?
The appendix or vermiform appendix.
p.29
Layers of the Gastrointestinal Tract
What are the four basic layers of the large intestine?
Mucosa, Submucosa, Muscularis, and Serosa.
p.6
Functions of the Digestive System
What are some solutes found in saliva?
Chloride ions, sodium, potassium, bicarbonate, and phosphate ions.
p.5
Anatomy and Functions of the Mouth
What is the function of the parotid duct?
To secrete saliva into the oral cavity opposite the second maxillary molar tooth.
p.2
Functions of the Digestive System
What is secretion in the digestive system?
The release of about 7 liters of water, acid, buffers, and enzymes into the GI tract to aid digestion.
p.7
Anatomy and Functions of the Mouth
What is the lingual frenulum?
A fold of mucous membrane that controls the posterior movement of the tongue.
p.10
Functions of the Digestive System
What is the main function of the esophagus?
To transfer the bolus from the mouth to the stomach.
p.11
Digestive Processes in the Stomach
What happens to the semisolid bolus in the stomach?
It is converted into liquid.
p.13
Gastrointestinal Tract and Accessory Organs
Where are G cells primarily located?
In the mucous of the pyloric antrum.
p.15
Digestive Processes in the Stomach
How do proton pumps function in parietal cells?
They actively transport H+ into the lumen and bring K+ back into the cell.
p.15
Gastrointestinal Tract and Accessory Organs
Where is the body of the pancreas situated?
It is left and superior to the head.
p.18
Pancreas and Its Role in Digestion
What role does sodium bicarbonate play in pancreatic juice?
It makes pancreatic juice slightly alkaline (pH 7.1 - 8.2) and stops the action of pepsin from the stomach.
p.18
Pancreas and Its Role in Digestion
What enzymes in pancreatic juice digest nucleic acids?
Ribonuclease and deoxyribonuclease.
p.21
Liver and Gallbladder Functions
What type of cells in the liver are responsible for phagocytosis?
Stellate reticuloendothelial (Kupffer) cells.
p.20
Liver and Gallbladder Functions
What is bilirubin and how is it processed by the liver?
Bilirubin is derived from aged red blood cells and is absorbed by the liver to be secreted into bile, where it is metabolized in the small intestine.
p.23
Mucosa of the Small Intestine
What hormones do endocrine cells in the small intestine secrete?
Secretin, cholecystokinin (CCK), and glucose-dependent insulinotropic peptide (GIP).
p.23
Mucosa of the Small Intestine
What is the role of brush border enzymes?
They have digestive functions and are located on the brush border formed by microvilli.
p.26
Functions of the Digestive System
What type of transport is used for the absorption of glucose and galactose?
Secondary active transport.
p.25
Mechanical and chemical digestion in small intestine
What are the two types of movements that result in mechanical digestion in the small intestine?
Segmentation and Migrating Motility Complex (MMC).
p.28
Anatomy and Functions of the Mouth
What are the four major regions of the large intestine?
Cecum, colon, rectum, and anal canal.
p.25
Chemical digestion in the small intestine
What is the role of maltase in carbohydrate digestion?
It splits maltose and maltriose into 2-3 units of glucose.
p.5
Anatomy and Functions of the Mouth
What is the primary function of salivary glands?
To release saliva into the oral cavity.
p.4
Layers of the Gastrointestinal Tract
What is the function of skeletal muscles in the muscularis layer?
They help in voluntary swallowing and defecation.
p.2
Gastrointestinal Tract and Accessory Organs
What is the gastrointestinal tract?
A continuous tube extending from the mouth to the anus, including organs like the mouth, pharynx, esophagus, stomach, small intestine, and large intestine.
p.4
Anatomy and Functions of the Mouth
What is the mouth also known as?
Oral cavity or Buccal cavity.
p.4
Anatomy and Functions of the Mouth
What is the function of the uvula?
It prevents the entrance of swallowed food and liquid into the nasal cavity.
p.9
Anatomy and Functions of the Mouth
What initiates mechanical digestion in the mouth?
Chewing or mastication by teeth.
p.9
Digestive Processes in the Stomach
What is the role of lingual lipase?
It breaks down triglycerides into diglycerides and fatty acids.
p.9
Anatomy and Functions of the Mouth
What are the three parts of the pharynx?
Nasopharynx, oropharynx, and laryngopharynx.
p.11
Gastrointestinal Tract and Accessory Organs
What is the role of the pyloric sphincter?
It regulates communication between the stomach and the duodenum.
p.15
Gastrointestinal Tract and Accessory Organs
What are the dimensions of the pancreas?
It is 12-15 cm long and 2-3 cm thick.
p.21
Liver and Gallbladder Functions
What is the primary storage function of the liver?
The liver stores glycogen, certain vitamins (A, B12, D, E, and K), and minerals (iron and copper).
p.21
Small Intestine: Structure and Function
Where does the ileum end?
At the ileocecal junction of the large intestine.
p.24
Layers of the Gastrointestinal Tract
What are the two layers of smooth muscle in the muscularis of the small intestine?
Outer longitudinal and inner circular muscles.
p.28
Anatomy and Functions of the Mouth
Where does the large intestine extend from and to?
From the ileum to the anus.
p.25
Chemical digestion in the small intestine
What enzymes are involved in the digestion of carbohydrates in the small intestine?
Pancreatic amylase and brush border enzymes.
p.25
Chemical digestion in the small intestine
What are the two nucleases found in pancreatic juice?
Ribonuclease (digests RNA) and deoxyribonuclease (digests DNA).
p.29
Anatomy and Functions of the Mouth
What is absent in the large intestine that is present in the small intestine?
Villi and circular folds.
p.29
Digestive Processes in the Stomach
What is mass peristalsis in the large intestine?
A strong peristaltic wave that drives colonic contents into the rectum.
p.30
Functions of the Digestive System
What causes flatulence in the large intestine?
Excessive production of gases by bacteria.
p.32
Disorders of the Digestive System
What is vomiting (emesis)?
The forcible expulsion of contents from the upper GI tract through the mouth.
p.33
Disorders of the Digestive System
What is the primary mode of transmission for Hepatitis B?
Sexual contact and contaminated syringes.
p.2
Overview of the Digestive System
What are the two main parts of the digestive system?
The gastrointestinal (GI) tract and the accessory digestive organs.
p.7
Anatomy and Functions of the Mouth
What is the function of extrinsic muscles of the tongue?
They move the tongue from side to side and in and out to maneuver food for chewing and swallowing.
p.12
Layers of the Gastrointestinal Tract
What are the four basic layers of the stomach wall?
Mucosa, submucosa, muscularis, and serosa.
p.7
Anatomy and Functions of the Mouth
Where are teeth located?
In the alveolar processes of the mandible and maxillae.
p.10
Digestive Processes in the Stomach
What are the three stages of swallowing?
1) Voluntary stage, 2) Pharyngeal stage, 3) Esophageal stage.
p.11
Functions of the Digestive System
What are the main functions of the stomach?
Mixing chamber, holding reservoir for food, and initiating digestion.
p.9
Anatomy and Functions of the Mouth
What do the oropharynx and laryngopharynx assist with?
They help in respiration and swallowing of food.
p.13
Functions of the Digestive System
What do the secretions of mucous, parietal, and chief cells collectively form?
Gastric juice (2 – 3 liters per day).
p.16
Pancreas and Its Role in Digestion
What is the size comparison between the pancreatic duct and the accessory duct?
The pancreatic duct is larger in size, while the accessory duct is smaller.
p.28
Large Intestine: Absorption and Feces Formation
What is the primary function of the large intestine?
Completion of absorption, production of certain vitamins, formation of feces, and expulsion of feces from the body.
p.27
Functions of the Digestive System
How are fat-soluble vitamins A, D, E, and K absorbed?
By simple diffusion through micelle formation.
p.29
Functions of the Digestive System
What are haustra in the large intestine?
Pouches formed by the tonic contraction of circular muscles.
p.33
Disorders of the Digestive System
What are peptic ulcers?
Ulcers that develop in areas of the GI tract exposed to acidic gastric juice.
p.12
Digestive Processes in the Stomach
What is the function of parietal cells in the stomach?
They produce intrinsic factor and hydrochloric acid.
p.9
Anatomy and Functions of the Mouth
What is the pharynx?
A funnel-shaped tube covered with mucous and composed of skeletal muscle.
p.11
Anatomy and Functions of the Mouth
What are the lesser and greater curvatures of the stomach?
The concave medial border is the lesser curvature, and the convex lateral border is the greater curvature.
p.13
Layers of the Gastrointestinal Tract
What are the three layers of smooth muscle in the muscularis?
Oblique muscles, circular muscles, and longitudinal muscles.
p.14
Digestive Processes in the Stomach
What nutrients are absorbed in the stomach?
Water, ions, short-chain fatty acids, certain drugs (like aspirin), and alcohol.
p.17
Pancreas and Its Role in Digestion
What are the endocrine cells in the pancreas called?
Pancreatic Islets or Islet of Langerhans.
p.22
Layers of the Gastrointestinal Tract
What are the basic layers of the small intestine?
The small intestine is composed of four basic layers.
p.23
Mucosa of the Small Intestine
What enzyme do Paneth cells secrete?
Lysozyme, which has a bactericidal function.
p.26
Functions of the Digestive System
What are the main electrolytes absorbed in the small intestine?
Na+, Ca2+, bicarbonate, chloride, iodide, nitrate.
p.25
Chemical digestion in the small intestine
What does α-Dextrinase do?
It acts on α-dextrin to produce glucose.
p.25
Chemical digestion in the small intestine
How are lipids digested in the small intestine?
Triglycerides are broken into fatty acids and monoglycerides by pancreatic lipase, and bile salts emulsify long chain fatty acids.
What initiates the intestinal phase of digestion?
Food entering the small intestine.
What does cholecystokinin (CCK) stimulate?
Secretion of pancreatic juice and contraction of the gallbladder.
p.32
Disorders of the Digestive System
What causes heartburn in GERD?
Irritation of the esophageal wall by hydrochloric acid (HCl) from stomach contents.
p.32
Disorders of the Digestive System
What is jaundice?
A yellowish coloration of the sclerae, skin, and mucous membranes due to a buildup of bilirubin.
p.16
Pancreas and Its Role in Digestion
What are the two ducts of the pancreas that open into the duodenum?
Pancreatic duct and accessory duct.
p.15
Digestive Processes in the Stomach
What do parietal cells secrete into the stomach lumen?
H+ and Cl- separately, resulting in the secretion of HCl.
p.17
Pancreas and Its Role in Digestion
What is the function of somatostatin?
It maintains glucagon and insulin levels in the body.
p.20
Liver and Gallbladder Functions
How does the liver process amino acids?
By removing the amino group to produce ATP or convert them into carbohydrates or fats, and converting harmful amino groups into urea.
p.20
Liver and Gallbladder Functions
What substances can the liver detoxify?
Alcohol and various drugs such as penicillin and erythromycin.
p.23
Mucosa of the Small Intestine
What are microvilli and where are they found?
Projections from the free membrane of absorptive cells that form a brush border.
p.24
Functions of the Digestive System
What are the protein-digesting enzymes found in brush border enzymes?
Aminopeptidase and dipeptidase.
p.27
Functions of the Digestive System
How are minerals like iron, potassium, magnesium, and phosphate absorbed in the digestive system?
By active or passive transport.
p.27
Functions of the Digestive System
How is Vitamin B12 absorbed in the digestive system?
It combines with intrinsic factor produced by the stomach and is absorbed in the ileum via active transport.
p.27
Functions of the Digestive System
What factors influence water absorption from the small intestine?
The absorption of electrolytes and nutrients to maintain osmotic balance with the blood.
What hormones are involved in hormonal regulation during the intestinal phase?
Cholecystokinin (CCK) and secretin.
p.32
Disorders of the Digestive System
What is gastroesophageal reflux disease (GERD)?
A condition where stomach contents reflux into the esophagus due to inadequate closure of the lower esophageal sphincter.
p.20
Liver and Gallbladder Functions
What is the role of bile salts in the small intestine?
They are used for emulsification and absorption of lipids.
p.26
Small Intestine: Structure and Function
What are nucleotides further digested into by brush-border enzymes?
Pentoses, phosphates, and nitrogenous bases.
p.24
Functions of the Digestive System
What types of enzymes are found in brush border enzymes?
Carbohydrate-digesting enzymes, protein-digesting enzymes, and nucleotide-digesting enzymes.
p.25
Mechanical and chemical digestion in small intestine
What is segmentation in the context of the small intestine?
Localized mixing contractions that help in mixing and absorption of chyme without pushing it forward.
p.25
Chemical digestion in the small intestine
What enzymes convert proteins into peptide units?
Trypsin, chymotrypsin, carboxypeptidase, and elastase.
p.27
Functions of the Digestive System
How does water absorption occur in the gastrointestinal tract?
All water absorption occurs via osmosis.
p.29
Layers of the Gastrointestinal Tract
What types of cells are primarily found in the mucosa of the large intestine?
Absorptive and goblet cells.
p.30
Functions of the Digestive System
What gases are released by bacteria during fermentation in the large intestine?
Hydrogen, CO2, and methane gas.
What is the effect of the intestinal phase on gastric emptying?
It slows the exit of chyme from the stomach.
p.30
Functions of the Digestive System
What are the three overlapping phases of digestion?
Cephalic phase, gastric phase, and intestinal phase.
p.33
Disorders of the Digestive System
What is the role of Helicobacter pylori in PUD?
It produces urease, which damages the protective mucous layer of the stomach.
p.32
Disorders of the Digestive System
What are the three main categories of jaundice?
Prehepatic, hepatic, and extrahepatic jaundice.
p.24
Functions of the Digestive System
Name the carbohydrate-digesting enzymes secreted by brush border enzymes.
α-dextrinase, maltase, sucrase, and lactase.
p.28
Anatomy and Functions of the Mouth
What is the cecum?
A small pouch-like organ next to the ileocecal sphincter.
p.29
Functions of the Digestive System
What do goblet cells secrete in the large intestine?
Mucus that lubricates the passage of colonic contents.
p.29
Layers of the Gastrointestinal Tract
What is the role of the muscularis layer in the large intestine?
It consists of circular and longitudinal muscles that aid in movement.
What stimulates the stretch receptors in the stomach?
Food distending the stomach.
p.30
Functions of the Digestive System
What pigment is produced from the decomposition of bilirubin by bacteria?
Stercobilin, which gives brown color to fecal material.
p.30
Digestive Processes in the Stomach
What happens during the gastric phase of digestion?
Neural and hormonal mechanisms regulate gastric secretion and motility.
p.32
Disorders of the Digestive System
What are some stimuli that can trigger vomiting?
Irritation and distension of the stomach, unpleasant sights, general anesthesia, dizziness, and certain drugs.
p.33
Disorders of the Digestive System
What lifestyle factors should be avoided to prevent PUD?
Cigarette smoke, alcohol, caffeine, and NSAIDs.
p.32
Disorders of the Digestive System
What causes gallstones?
Insufficient bile salts or lecithin or excessive cholesterol in bile.
p.33
Disorders of the Digestive System
How does Hepatitis C compare to Hepatitis B?
Clinically similar and can also cause cirrhosis and liver cancer.
p.24
Functions of the Digestive System
What role does intestinal juice play in digestion?
It mixes with pancreatic juices and provides a liquid medium for absorption from chyme into the small intestine.
p.28
Anatomy and Functions of the Mouth
How is the colon divided?
Into ascending colon, transverse colon, descending colon, and sigmoid colon.
p.29
Digestive Processes in the Stomach
What occurs during haustral churning in the colon?
Hustra remain relaxed and distend when filled, then contract to move contents.
p.30
Functions of the Digestive System
What is the role of bacteria in chemical digestion in the large intestine?
Bacteria ferment remaining carbohydrates and convert proteins to amino acids and simpler substances.
p.30
Large Intestine: Absorption and Feces Formation
What is the composition of feces?
Water, inorganic salts, sloughed-off epithelial cells, bacteria, products of bacterial decomposition, unabsorbed digested materials, and indigestible parts of food.
p.33
Disorders of the Digestive System
What are the three distinct causes of Peptic Ulcer Disease (PUD)?
1) Helicobacter pylori, 2) NSAIDs, 3) Hypersecretion of HCl.
p.33
Disorders of the Digestive System
What are the symptoms of Hepatitis A?
Loss of appetite, malaise, nausea, diarrhea, fever, and chills.
p.26
Functions of the Digestive System
What is the role of micelles in lipid absorption?
They carry fatty acids and monoglycerides to absorptive cells and help solubilize other large hydrophobic molecules.
p.25
Mechanical and chemical digestion in small intestine
What does the Migrating Motility Complex (MMC) do?
It is a type of peristaltic movement that pushes chyme forward when the volume in the small intestine decreases.
p.28
Anatomy and Functions of the Mouth
What guards the opening of the anal canal?
Internal sphincter of smooth muscles and external sphincter of skeletal muscles.
p.32
Functions of the Digestive System
What role does secretin play in the digestive system?
Secretin buffers acid in chyme that reaches the duodenum and slows acid production in the stomach.
p.33
Disorders of the Digestive System
How is Hepatitis A primarily spread?
Via fecal contamination of objects (fecal-oral route).
p.33
Disorders of the Digestive System
What are the potential long-term effects of Hepatitis B?
Cirrhosis and possibly liver cancer.
What is the role of gastrin in gastric secretion?
Stimulates gastric glands to secrete gastric juice.
What does secretin stimulate when acidic chyme enters the duodenum?
Flow of pancreatic juice rich in bicarbonate ions.
p.32
Disorders of the Digestive System
What lifestyle factors can worsen GERD symptoms?
Drinking alcohol and smoking.
p.30
Functions of the Digestive System
How does the liver contribute to the detoxification process in the large intestine?
It converts toxic substances like indole and hydrogen sulfide into less toxic substances.
p.30
Functions of the Digestive System
What activates the cephalic phase of digestion?
Smell, sight, thought, or initial taste of food.
p.33
Disorders of the Digestive System
What is the most common complication of peptic ulcers?
Bleeding, which can lead to anemia.
p.33
Disorders of the Digestive System
What is hepatitis?
An inflammation of the liver caused by viruses, drugs, and chemicals.
