p.17
Fluid and Electrolyte Balance
How does natriuretic peptide affect aldosterone levels?
It decreases aldosterone levels.
p.19
Integrated Control of Blood Volume and Osmolarity
What systems are involved in the integrated control of blood volume and osmolarity?
Cardiovascular, renin-angiotensin, renal, and hypothalamic systems.
p.1
Homeostasis and Body Balance
What is the equation that represents the maintenance of homeostasis in the body?
Input + production = utilization + output.
p.8
Osmotic Gradient and Urine Concentration
Which nephrons establish the vertical osmotic gradient?
Juxtamedullary nephrons (loop of Henle).
p.3
Fluid and Electrolyte Balance
Why are we concerned with water and ion balance?
Because it is essential for maintaining homeostasis and proper functioning of the body's systems.
p.6
Fluid and Electrolyte Balance
What happens to urine concentration when fluid is lost from the body?
Concentrated urine is produced to prevent additional fluid loss.
p.14
Hormonal Regulation of Fluid Balance
How does increased plasma osmolarity affect vasopressin release?
Increased plasma osmolarity stimulates osmoreceptors in the hypothalamus, leading to the release of vasopressin.
p.14
Hormonal Regulation of Fluid Balance
How does decreased blood volume influence vasopressin release?
Decreased blood volume is detected by baroreceptors, which signal the hypothalamus to release vasopressin.
p.10
Osmotic Gradient and Urine Concentration
What happens to urea in the distal collecting duct?
The distal collecting duct is permeable to urea, allowing concentrated urea to move into the renal interstitium.
p.24
Acid-Base Balance and pH Homeostasis
What reaction does carbonic anhydrase (CA) catalyze in intercalated cells?
CA converts CO2 and water to H+ and HCO3-.
p.8
Osmotic Gradient and Urine Concentration
What is the entire functional organization involving the vertical osmotic gradient known as?
The medullary countercurrent system.
p.16
Role of Aldosterone in Sodium and Potassium Balance
What is the primary function of aldosterone in sodium balance?
To facilitate the reabsorption of sodium and the secretion of potassium.
p.18
Behavioral Mechanisms in Fluid Regulation
What behavioral mechanism helps replace fluid loss in the body?
Drinking replaces fluid loss.
p.8
Osmotic Gradient and Urine Concentration
What role does the vasa recta play in the medullary countercurrent system?
The vasa recta preserve/maintain the vertical osmotic gradient while providing blood to the renal medulla.
p.8
Osmotic Gradient and Urine Concentration
How do collecting ducts use the vertical osmotic gradient?
Collecting ducts use the vertical osmotic gradient to concentrate urine.
p.25
Acid-Base Balance and pH Homeostasis
How is the polarity of type B intercalated cells different from type A cells?
The polarity is reversed, meaning the same transport systems take place but on the opposite sides of the cells.
p.6
Fluid and Electrolyte Balance
What role do the kidneys play in water balance?
The kidneys conserve volume but cannot replace lost volume.
p.12
Osmotic Gradient and Urine Concentration
What role do collecting ducts play in water balance?
Collecting ducts use the vertical osmotic gradient to regulate water balance.
p.25
Acid-Base Balance and pH Homeostasis
What do type B intercalated cells secrete and reabsorb during alkalosis?
They secrete HCO3- and reabsorb H+.
p.1
Fluid and Electrolyte Balance
What is the daily intake of fluid required to maintain homeostasis?
Approximately 2 liters of fluid.
p.15
Fluid and Electrolyte Balance
What is the primary homeostatic response to salt ingestion?
The body increases water retention to dilute the excess salt, primarily through the release of antidiuretic hormone (ADH).
p.4
Fluid and Electrolyte Balance
What are the primary systems involved in the body's response to changes in blood volume and pressure?
The cardiovascular system and the kidneys.
p.20
Acid-Base Balance and pH Homeostasis
What happens to neurons during alkalosis?
Neurons become hyperexcitable, leading to sensory changes and sustained contractions
p.3
Fluid and Electrolyte Balance
How do Na+ and water affect the body?
They affect extracellular fluid (ECF) volume and osmolarity, which in turn affect cell volume.
p.3
Fluid and Electrolyte Balance
What is the role of K+ in the body?
K+ affects cardiac and muscle function.
p.3
Fluid and Electrolyte Balance
What functions are influenced by Ca2+?
Ca2+ affects exocytosis, muscle contraction, and other functions.
p.18
Role of Aldosterone in Sodium and Potassium Balance
What role does aldosterone play in potassium homeostasis?
Aldosterone plays a critical role in potassium homeostasis by facilitating the renal excretion of potassium ions.
p.24
Acid-Base Balance and pH Homeostasis
What type of cells in the collecting duct are involved in pH homeostasis?
Type A intercalated cells.
p.1
Fluid and Electrolyte Balance
What is the body's task in maintaining fluid and electrolyte balance?
To excrete what comes in if the body does not need it.
p.14
Hormonal Regulation of Fluid Balance
Which organ releases vasopressin?
The posterior pituitary gland releases vasopressin.
p.3
Fluid and Electrolyte Balance
Which systems are involved in the maintenance of water and ion balance?
Respiratory and cardiovascular systems, renal and behavioral responses.
p.15
Hormonal Regulation of Fluid Balance
What is the effect of increased ADH on the kidneys?
Increased ADH causes the kidneys to reabsorb more water, reducing urine output and diluting the blood's salt concentration.
p.15
Fluid and Electrolyte Balance
How does the body balance electrolytes after salt ingestion?
The body retains water to dilute the salt and may excrete excess sodium through urine, regulated by hormones like ADH and aldosterone.
p.7
Fluid and Electrolyte Balance
What is the driving force for water reabsorption throughout the entire length of the nephrons?
Osmotic gradient between the tubular lumen and surrounding interstitial fluid.
p.12
Osmotic Gradient and Urine Concentration
How do collecting ducts contribute to the regulation of water balance?
By utilizing the vertical osmotic gradient.
p.10
Osmotic Gradient and Urine Concentration
What are the two main processes that establish the medullary vertical osmotic gradient?
Countercurrent multiplication and urea recycling.
p.1
Fluid and Electrolyte Balance
What other electrolytes need to be balanced in the body besides NaCl?
Electrolytes such as K+, H+, Ca2+, and HCO3-.
p.4
Fluid and Electrolyte Balance
What triggers homeostatic reflexes related to fluid and electrolyte balance?
Changes in blood volume and blood pressure.
p.20
Acid-Base Balance and pH Homeostasis
What happens to neurons during acidosis?
Neurons become less excitable and CNS depression results
p.17
Fluid and Electrolyte Balance
What effect does natriuretic peptide have on vasopressin levels?
It decreases vasopressin levels.
p.4
Fluid and Electrolyte Balance
How does the cardiovascular system respond to changes in blood volume and pressure?
By adjusting cardiac output and vasodilation or vasoconstriction.
p.6
Fluid and Electrolyte Balance
What is the only way to replace lost fluid in the body?
By adding water from an external source.
p.3
Fluid and Electrolyte Balance
What must the body maintain to ensure proper function?
The body must maintain mass balance.
p.19
Integrated Control of Blood Volume and Osmolarity
Which system plays a key role in regulating blood volume and osmolarity?
The renin-angiotensin system.
p.18
Behavioral Mechanisms in Fluid Regulation
What stimulates salt appetite in the body?
Low sodium levels stimulate salt appetite.
p.10
Osmotic Gradient and Urine Concentration
What is the role of the proximal cortical collecting duct in urea recycling?
It is permeable to water, allowing water to move out and causing the concentration of urea in the duct.
p.9
Osmotic Gradient and Urine Concentration
What are the two main processes that establish the medullary vertical osmotic gradient?
Countercurrent multiplication and urea recycling.
p.11
Osmotic Gradient and Urine Concentration
What role do the vasa recta play in the renal medulla?
They preserve/maintain the vertical osmotic gradient while providing blood to the renal medulla.
p.20
Acid-Base Balance and pH Homeostasis
What can severe CNS depression due to acidosis lead to?
Cease respiratory center function and death
p.16
Role of Aldosterone in Sodium and Potassium Balance
On which cells does aldosterone act to regulate sodium balance?
Principal cells in the distal tubule and cortical collecting duct.
p.18
Role of Aldosterone in Sodium and Potassium Balance
How does aldosterone affect potassium ion levels in the body?
Aldosterone facilitates the renal excretion of potassium ions.
p.19
Fluid and Electrolyte Balance
What are the main factors controlled to maintain fluid and electrolyte balance?
Blood volume and osmolarity.
p.19
Integrated Control of Blood Volume and Osmolarity
What role does the hypothalamus play in fluid and electrolyte balance?
It helps regulate osmolarity and triggers thirst mechanisms.
p.24
Acid-Base Balance and pH Homeostasis
What do Type A intercalated cells secrete and reabsorb during acidosis?
They secrete H+ and reabsorb HCO3-.
p.6
Fluid and Electrolyte Balance
How can the glomerular filtration rate (GFR) be adjusted?
GFR can be adjusted based on the body's fluid volume.
p.11
Kidney Function in Water and Salt Regulation
How does blood supply reach the renal medulla?
Via the vasa recta, which descend from the cortex to the medulla and loop back up to the cortex.
p.23
Fluid and Electrolyte Balance
What occurs after CO2 diffuses into the proximal tubule cell?
It combines with water to form H+ and HCO3-.
p.15
Integrated Control of Blood Volume and Osmolarity
What is the consequence of excessive salt ingestion on blood pressure?
Excessive salt ingestion can lead to increased blood volume and higher blood pressure due to water retention.
p.17
Fluid and Electrolyte Balance
What is the result of increased GFR due to natriuretic peptide release?
Increased NaCl and H2O excretion.
p.8
Osmotic Gradient and Urine Concentration
What enables the kidneys to produce urine of varying concentration?
The medullary vertical osmotic gradient in conjunction with the hormone vasopressin.
p.10
Osmotic Gradient and Urine Concentration
How is urea recycled in the kidney?
Urea moves from the distal collecting duct into the renal interstitium and can be absorbed into the ascending limb fluid, where it is recycled.
p.20
Acid-Base Balance and pH Homeostasis
What can a change in intracellular pH result in?
Denature intracellular proteins (e.g., enzymes and membrane channels)
p.15
Hormonal Regulation of Fluid Balance
Which hormone is released in response to high salt intake to promote water retention?
Antidiuretic hormone (ADH).
p.11
Countercurrent Multiplication and Urea Recycling
What is countercurrent exchange in the medulla of the kidney?
It is the process by which the vasa recta maintain the osmotic gradient by reabsorbing solutes and removing water on the descent, and allowing solutes to diffuse back and water to move into the capillaries on the ascent.
p.4
Fluid and Electrolyte Balance
What role do the kidneys play in fluid and electrolyte balance?
They excrete salts and water in urine or conserve water to minimize further volume loss.
p.4
Behavioral Mechanisms in Fluid Regulation
How does the body respond behaviorally to changes in blood volume and pressure?
Thirst causes water intake.
p.23
Fluid and Electrolyte Balance
What happens to H+ after it is formed in the proximal tubule cell?
It is secreted again and excreted.
p.25
Acid-Base Balance and pH Homeostasis
What type of cells in the collecting duct are involved in pH homeostasis?
Type B intercalated cells.
p.19
Fluid and Electrolyte Balance
Which organ systems are primarily responsible for maintaining fluid and electrolyte balance?
The renal and cardiovascular systems.
p.10
Hormonal Regulation of Fluid Balance
What effect does vasopressin have on the collecting duct?
Vasopressin increases the permeability of the collecting duct to urea.
p.4
Fluid and Electrolyte Balance
Which receptors are involved in detecting changes in blood volume and pressure?
Volume receptors in atria, endocrine cells in atria, and carotid and aortic baroreceptors.
p.24
Acid-Base Balance and pH Homeostasis
How is H+ secretion in the collecting duct similar to that in the proximal tubule?
Both involve the secretion of H+, but in the collecting duct, H+-K+-ATPase is involved.
p.23
Fluid and Electrolyte Balance
What is the role of the Na+-H+ antiport in the proximal tubule?
It secretes H+ into the filtrate.
p.9
Osmotic Gradient and Urine Concentration
How is the 200-mOsm gradient established in the ascending limb?
By Na+ pumps pumping out NaCl to the interstitium.
p.9
Osmotic Gradient and Urine Concentration
What happens to water in the descending limb during countercurrent multiplication?
Water diffuses from the descending limb into the interstitial fluid.
p.9
Osmotic Gradient and Urine Concentration
What is the characteristic of the descending limb in the countercurrent multiplication process?
It is water permeable and has no active Na+ pump.
p.5
Fluid and Electrolyte Balance
What must be equal to maintain a constant volume of water in the body?
Intake must equal output.
p.14
Hormonal Regulation of Fluid Balance
What triggers the release of vasopressin?
Increased plasma osmolarity and decreased blood volume or blood pressure trigger the release of vasopressin.
p.20
Acid-Base Balance and pH Homeostasis
What can severe alkalosis lead to in terms of respiratory function?
Paralyze respiratory muscle and death
p.17
Fluid and Electrolyte Balance
What is the effect of natriuretic peptide on blood pressure?
It decreases blood pressure.
p.11
Countercurrent Multiplication and Urea Recycling
What occurs in the vasa recta during its ascent?
Solutes diffuse back to the interstitium and water moves back into the capillaries.
p.2
Fluid and Electrolyte Balance
What are the four parameters that homeostatic control mechanisms aim to maintain?
Fluid volume, osmolarity, concentration of individual ions, and pH.
p.9
Osmotic Gradient and Urine Concentration
What is the final result of the repeated steps in countercurrent multiplication?
The final vertical osmotic gradient is established.
p.7
Osmotic Gradient and Urine Concentration
What creates hyposmotic fluid in the nephron?
Removal of solute in the thick ascending limb.
p.21
Acid-Base Balance and pH Homeostasis
What acids are produced from fatty acids and amino acids?
Ketoacids and lactic acid
p.14
Hormonal Regulation of Fluid Balance
What is vasopressin?
Vasopressin, also known as antidiuretic hormone (ADH), is a hormone that regulates water balance in the body.
p.15
Fluid and Electrolyte Balance
How does the body detect increased salt levels in the blood?
Osmoreceptors in the hypothalamus detect increased osmolarity due to high salt levels.
p.24
Acid-Base Balance and pH Homeostasis
How does HCO3- leave the intercalated cells to the interstitial space?
Through the HCO3--Cl- antiporter.
p.15
Role of Aldosterone in Sodium and Potassium Balance
What role does aldosterone play in response to salt ingestion?
Aldosterone promotes sodium reabsorption in the kidneys, which can help regulate blood pressure and fluid balance.
p.11
Countercurrent Multiplication and Urea Recycling
What happens in the vasa recta during its descent?
The vasa recta reabsorbs solutes from the medullary interstitium and removes water.
p.6
Fluid and Electrolyte Balance
What happens when extra fluid is added to the body?
Excess water is excreted in urine.
p.14
Hormonal Regulation of Fluid Balance
How does vasopressin affect blood pressure?
By increasing water reabsorption and blood volume, vasopressin helps to raise blood pressure.
p.7
Osmotic Gradient and Urine Concentration
What happens to the fluid leaving the proximal tubule?
It becomes progressively more concentrated in the descending limb.
p.22
Acid-Base Balance and pH Homeostasis
How do buffers help moderate changes in pH?
Buffers combine with or release H+ to moderate changes in pH.
p.9
Osmotic Gradient and Urine Concentration
What is the characteristic of the ascending limb in the countercurrent multiplication process?
It is water impermeable and has active Na+ transport.
p.4
Fluid and Electrolyte Balance
What is the effect of volume receptors in the atria and baroreceptors in the carotid and aortic arteries?
They trigger homeostatic reflexes to maintain blood volume and pressure.
p.11
Osmotic Gradient and Urine Concentration
Why don't the vasa recta wash away the concentration gradient in the renal medulla?
Because of the countercurrent exchange mechanism, which allows solutes and water to be reabsorbed and diffused back in a controlled manner.
p.13
Osmotic Gradient and Urine Concentration
What happens to ions and water in the ascending limb of the Loop of Henle?
Ions are reabsorbed but no water.
p.2
Acid-Base Balance and pH Homeostasis
How do the lungs contribute to fluid and electrolyte balance?
By losing water and helping to remove H+ and HCO3- through breathing out CO2.
p.21
Acid-Base Balance and pH Homeostasis
Which substances act as buffers in cells?
Proteins, hemoglobin, and phosphates
p.14
Hormonal Regulation of Fluid Balance
How does stress influence vasopressin release?
Stress can increase vasopressin release as part of the body's response to maintain fluid balance.
p.5
Fluid and Electrolyte Balance
What is insensible water loss?
Water loss that occurs through the skin and lungs without being noticed.
p.22
Acid-Base Balance and pH Homeostasis
What happens to pH during hypoventilation?
pH decreases (becomes more acidic).
p.7
Osmotic Gradient and Urine Concentration
How does the fluid leaving the proximal tubule compare to the fluid in the descending limb?
The fluid leaving the proximal tubule is isosmotic, while it becomes progressively more concentrated in the descending limb.
p.9
Osmotic Gradient and Urine Concentration
What occurs when a new mass of 300 mOsm fluid enters from the proximal tubule?
The ascending limb pump and descending limb passive fluxes reestablish the 200-mOsm gradient.
p.23
Fluid and Electrolyte Balance
What is glutamine metabolized into in the proximal tubule cell?
Ammonium ion (NH4+) and HCO3-.
p.13
Hormonal Regulation of Fluid Balance
What is the role of hormones in the collecting duct?
They control the permeability to water, affecting urine osmolarity.
p.14
Kidney Function in Water and Salt Regulation
What role does vasopressin play in the kidneys?
Vasopressin increases water reabsorption in the kidneys, reducing urine output and conserving water.
p.4
Fluid and Electrolyte Balance
What are the systemic responses to changes in blood volume and pressure?
Adjustments in ECF and ICF volume and blood pressure.
p.22
Acid-Base Balance and pH Homeostasis
What are the main buffers in cells?
Proteins, hemoglobin, and phosphates.
p.21
Acid-Base Balance and pH Homeostasis
What are the sources of acid input in the body?
Diet (e.g., fatty acids, amino acids), metabolism (e.g., anaerobic respiration), and disease (e.g., diabetes)
p.6
Fluid and Electrolyte Balance
What mechanism is regulated to control water reabsorption in the kidneys?
Regulated H2O reabsorption.
p.23
Fluid and Electrolyte Balance
What happens to NH4+ in the proximal tubule?
It is secreted and excreted.
p.7
Osmotic Gradient and Urine Concentration
What does urine osmolarity depend on?
Reabsorption in the collecting duct.
p.22
Acid-Base Balance and pH Homeostasis
What happens to pH during hyperventilation?
pH increases (becomes more alkaline).
p.14
Hormonal Regulation of Fluid Balance
What is the effect of alcohol on vasopressin release?
Alcohol inhibits the release of vasopressin, leading to increased urine production and dehydration.
p.22
Acid-Base Balance and pH Homeostasis
What are the three main mechanisms for maintaining pH homeostasis?
Buffers, ventilation, and renal regulation.
p.23
Fluid and Electrolyte Balance
What are the two pathways involved in H+ secretion and HCO3- reabsorption in the proximal tubule?
Pathway A (steps 1-5) and Pathway B (steps 6-7).
p.7
Osmotic Gradient and Urine Concentration
What is reabsorbed in the thick ascending limb of the Loop of Henle?
Ions are reabsorbed but no water.
p.7
Osmotic Gradient and Urine Concentration
What is reabsorbed in the descending limb of the Loop of Henle?
Only water is reabsorbed.
p.22
Acid-Base Balance and pH Homeostasis
How does renal regulation manage pH disturbances?
By directly excreting or reabsorbing H+ and indirectly by changing the excretion or reabsorption of HCO3-.
p.13
Osmotic Gradient and Urine Concentration
What happens to water in the descending limb of the Loop of Henle?
Only water is reabsorbed.
