Week 18 / Renal system 2

Question 1

What is the role of the distal convoluted tubules in the nephron?

Answer 1

A: The distal convoluted tubules of several nephrons empty into a single collecting duct.

Question 2

Where do collecting ducts from nephrons converge?

Answer 2

Collecting ducts unite and converge into several hundred large papillary ducts.

Question 3

Into which structures do papillary ducts drain?

Answer 3

Papillary ducts drain into the minor calyces, which lead to the major calyces, renal pelvis, and ureters.

Question 4

Function of nephron:

What is the primary function of the renal corpuscle?

Answer 4

Filtration of blood plasma into the nephron.

Question 5

Function of nephron:

What occurs in the renal tubule and collecting duct?

Answer 5

Tubular reabsorption: Substances are reabsorbed from the fluid into the blood.
Tubular secretion: Substances are secreted from the blood into the tubular fluid.

Question 6

Function of nephron:
Q: What is the role of the afferent arteriole in the nephron?

Answer 6

A: It carries blood to the glomerulus for filtration.

Question 7

Function of nephron:
Q: What is the function of the glomerular capsule (Bowman’s capsule)?

Answer 7

A: It collects the filtrate from the glomerulus.

Question 8

Function of nephron:
Q: What is the significance of the efferent arteriole in nephron function?

Answer 8

A: It carries blood away from the glomerulus and leads to the peritubular capillaries.

Question 9

Function of nephron:
Q: What is the role of peritubular capillaries?

Answer 9

A: They allow reabsorbed substances from the renal tubule to enter back into the blood.

Question 10

Function of nephron:
Q: What does the fluid in the renal tubule eventually become?

Answer 10

A: Urine, which contains excreted substances.

Question 11

Function of nephron:
Q: What happens to blood after reabsorption and secretion processes in the nephron?

Answer 11

A: It contains reabsorbed substances and continues through the circulatory system.

Question 12

Renal Corpuscle :
Flashcard 1
Q: What two main structures make up the renal corpuscle?

Answer 12

A: The glomerular (Bowman’s) capsule and the glomerulus.

Question 13

Renal Corpuscle :
Flashcard 2
Q: What is the function of the parietal layer of the glomerular (Bowman’s) capsule?

Answer 13

A: It forms the outer structural layer of the capsule.

Question 14

Renal Corpuscle :
Flashcard 3
Q: What is the role of the afferent arteriole in the renal corpuscle?

Answer 14

A: It brings blood into the glomerulus for filtration.

Question 15

Renal Corpuscle :
Flashcard 4
Q: What is the function of juxtaglomerular cells?

Answer 15

A: They secrete renin and help regulate blood pressure.

Question 16

Renal Corpuscle :
Flashcard 5
Q: What are mesangial cells and their function?

Answer 16

A: They provide structural support, regulate blood flow in the glomerulus, and clear debris.

Question 17

Renal Corpuscle :
Flashcard 6
Q: What is the capsular space in the renal corpuscle?

Answer 17

A: It is the space between the parietal and visceral layers of the Bowman’s capsule where filtrate collects.

Question 18

Renal Corpuscle :
Flashcard 7
Q: What is the macula densa, and what is its role?

Answer 18

A: It is a group of specialized cells in the ascending limb of the nephron loop that detect sodium concentration in the filtrate and regulate glomerular filtration rate.

Question 19

Renal Corpuscle :
Flashcard 8
Q: What is the function of the efferent arteriole in the renal corpuscle?

Answer 19

A: It carries blood away from the glomerulus after filtration.

Question 20

Renal Corpuscle :
*Flashcard 9**
Q: What structure leads to the proximal convoluted tubule?

Answer 20

A: The capsular space funnels filtrate into the proximal convoluted tubule.

Question 21

Renal Corpuscle :
Flashcard 10
Q: What is a podocyte, and where is it located?

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Answer 21

A: A podocyte is a cell of the visceral layer of the glomerular capsule that wraps around glomerular capillaries.

Question 22

Renal Corpuscle :
Q: What are pedicels in the renal corpuscle?

Answer 22

A: Pedicels are the foot-like extensions of podocytes that form filtration slits.

Question 23

Renal Corpuscle :
Flashcard 12
Q: What is the role of the endothelium of the glomerulus?

Answer 23

A: It forms part of the filtration membrane, allowing passage of water and small solutes while blocking large molecules like proteins

Question 24

Glomerular Filtration :
Flashcard 1
Q: What is the glomerular filtration process?

Flashcard 2
Q: What are the three key components of the filtration membrane?

Flashcard 3
Q: What is the role of the capillary endothelium in the filtration membrane?

Flashcard 4
Q: How does the basement membrane function in filtration?

Flashcard 5
Q: What is the significance of the foot processes of podocytes in glomerular filtration?

Flashcard 6
Q: What is a filtration slit?

Flashcard 7
Q: What is the role of the slit diaphragm in the filtration process?

Flashcard 8
Q: What happens to the filtrate once it passes through the filtration membrane?

Flashcard 9
Q: What is a fenestration (pore) in the capillary endothelium?

Answer 24

A: It is the process by which blood plasma is filtered through the filtration membrane in the glomerulus to form filtrate in the capsular space.

A:
1. Capillary endothelium
2. Basement membrane
3. Foot processes of podocytes

A: It contains fenestrations (pores) that allow plasma and small molecules to pass while blocking blood cells.

A: It acts as a molecular sieve, preventing large proteins from passing into the filtrate while allowing water and small solutes through.

A: They create filtration slits that allow fluid and small molecules to pass while preventing the passage of larger molecules like proteins.

A: A narrow gap between the foot processes of podocytes through which filtered fluid passes.

A: It spans the filtration slits to provide an additional barrier, allowing selective filtration of smaller molecules.

A: It enters the capsular space, becoming the fluid that moves into the renal tubule for further processing.

A: It is a small opening that permits the passage of water, ions, and small solutes but blocks blood cells.

Question 25

Pressures Involved in Glomerular Filtration **Q:** What is glomerular (blood) hydrostatic pressure and its typical value? --- **Flashcard 2** **Q:** What is blood colloid osmotic pressure and its typical value? --- **Flashcard 3** **Q:** What is capsular hydrostatic pressure and its typical value? --- **Flashcard 4** **Q:** How do these pressures determine the net filtration pressure (NFP)? **Flashcard 5** **Q:** What does a positive net filtration pressure (NFP) indicate?

Answer 25

**A:** It is the blood pressure in the glomerular capillaries, driving fluid and solutes out of the blood and into the capsular space. **Typical value:** 55 mm Hg. **A:** It is the osmotic pressure exerted by proteins in the blood, pulling water back into the capillaries from the filtrate. **Typical value:** 30 mm Hg. **A:** It is the pressure exerted by the fluid already in the capsular space, opposing filtration. **Typical value:** 15 mm Hg. Typical calculation: NFP = 55 mm Hg – (30 mm Hg + 15 mm Hg) = **10 mm Hg**. **A:** It indicates that filtration is occurring, with fluid moving from the glomerulus into the capsular space

Question 26

Regulation of Glomerular Filtration Rate (GFR) --- **Flashcard 1** **Q:** How do intrinsic mechanisms regulate GFR? --- **Flashcard 2** **Q:** What are the two main intrinsic mechanisms for GFR regulation? --- **Flashcard 3** **Q:** How do extrinsic mechanisms regulate GFR? --- **Flashcard 4** **Q:** What are the two main extrinsic mechanisms for GFR regulation? --- **Flashcard 5** **Q:** What is the primary goal of intrinsic GFR regulation? --- **Flashcard 6** **Q:** What is the primary goal of extrinsic GFR regulation?

Answer 26

**A:** Intrinsic mechanisms directly regulate GFR by adjusting the diameter of afferent and efferent arterioles to maintain a stable GFR despite moderate changes in blood pressure (80–180 mm Hg mean arterial pressure). **A:** 1. **Myogenic mechanism**: Responds to changes in blood pressure by contracting or relaxing the afferent arteriole. 2. **Tubuloglomerular feedback**: The macula densa detects changes in NaCl levels in the filtrate and adjusts arteriole diameter accordingly. **A:** Extrinsic mechanisms indirectly regulate GFR by maintaining systemic blood pressure, ensuring sufficient pressure for filtration in the kidneys. **A:** 1. **Sympathetic nervous system**: Constricts afferent arterioles during stress or low blood pressure, reducing GFR to prioritize blood flow to vital organs. 2. **Renin-angiotensin-aldosterone system (RAAS)**: Activates in response to low blood pressure, increasing systemic blood pressure and restoring GFR. **A:** To maintain a consistent GFR and kidney function despite fluctuations in blood pressure. **A:** To maintain systemic blood pressure to ensure adequate filtration pressure in the kidneys.

Question 27

Hormonal Regulation of Glomerular Filtration Rate (GFR) **Flashcard 1** **Q:** Which two hormones contribute to the regulation of GFR? **Flashcard 2** **Q:** What is the effect of angiotensin II on GFR? **Flashcard 3** **Q:** What triggers the release of atrial natriuretic peptide (ANP)? **Flashcard 4** **Q:** How does ANP affect the glomerulus and GFR? **Flashcard 5** **Q:** What is the primary role of ANP in the regulation of GFR?

Answer 27

**A:** Angiotensin II and Atrial Natriuretic Peptide (ANP). **A:** Angiotensin II is a potent vasoconstrictor of both afferent and efferent arterioles, which reduces GFR by decreasing blood flow through the glomerulus. **A:** A sudden large increase in blood pressure stretches the cardiac atria, causing the release of ANP. **A:** ANP causes the glomerulus to relax, increasing the surface area available for filtration, which enhances GFR. **A:** To increase GFR and promote the excretion of excess fluid and sodium, helping to lower blood pressure.

Question 28

Flashcard Set: Hormones and Homeostasis in Kidney Function **Flashcard 1** **Q:** Which five hormones regulate renal tubule function and help maintain homeostasis? What do these hormones have an effect on to and extent? What do they maintain? **Flashcard 2** **Q:** What is the role of angiotensin II in kidney function? **Flashcard 3** **Q:** How does antidiuretic hormone (ADH) regulate water balance? **Flashcard 4** **Q:** What is the function of aldosterone in the renal system? **Flashcard 5** **Q:** How does atrial natriuretic peptide (ANP) affect GFR and blood pressure? **Flashcard 6** **Q:** What role does parathyroid hormone (PTH) play in kidney function?

Answer 28

**A:** 1. **Angiotensin II** 2. **Antidiuretic Hormone (ADH)** 3. **Aldosterone** 4. **Atrial Natriuretic Peptide (ANP)** 5. **Parathyroid Hormone (PTH)** the extent of Nat, CM, Cart, and water reabsorption as well as K* secretion by the renal tubules. homeostasis of not only renal blood flow and B.P., but systemic blood flow and B.P. **A:** It promotes vasoconstriction of arterioles, enhances Na+ and water reabsorption, and stimulates aldosterone release, increasing blood pressure and GFR. **A:** ADH increases water reabsorption in the collecting ducts by promoting the insertion of aquaporins, reducing urine output and increasing blood volume. **A:** Aldosterone enhances Na + and water reabsorption while promoting K +secretion, helping to regulate blood pressure and electrolyte balance. **A:** ANP increases GFR by relaxing the glomerulus, promoting the excretion of Na + and water, which reduces blood volume and blood pressure. **A:** PTH increases calcium reabsorption in the renal tubules and decreases phosphate reabsorption, helping to regulate calcium and phosphate balance in the blood.

Question 29

Flashcard 1 Q: Where is antidiuretic hormone (ADH) released from, and in response to what condition? Flashcard 2 Q: How does ADH affect water reabsorption in the kidneys? Q: What happens to water permeability in the absence of ADH? Q: What is facultative water reabsorption? What role does ADH play in maintaining homeostasis?

Answer 29

A: ADH is released by the posterior pituitary in response to low blood flow in the hypothalamus. A: ADH increases facultative water reabsorption by enhancing the water permeability of principal cells in the last part of the distal convoluted tubule and throughout the collecting duct. A: The apical membranes of principal cells become almost impermeable to water, reducing water reabsorption and leading to increased urine output. A: It is the reabsorption of water in response to the body's hydration needs, regulated by ADH. A: ADH helps conserve body water, maintain blood volume, and regulate blood pressure by adjusting water reabsorption in the kidneys.

Question 30

Q: Where is parathyroid hormone (PTH) released from? Q: What effect does PTH have on calcium reabsorption in the kidneys? Flashcard 3 Q: How does PTH affect phosphate (HPO ) reabsorption in the kidneys? Flashcard 4 Q: What is the primary role of PTH in regulating mineral balance? Flashcard 5 Q: Why is it important for PTH to inhibit phosphate reabsorption?

Answer 30

A: PTH is released by the parathyroid glands. A: PTH stimulates cells in the early distal convoluted tubule to reabsorb calcium (Ca 2+) into the blood. A: PTH inhibits phosphate reabsorption in the proximal convoluted tubule, promoting phosphate excretion in the urine. A: PTH helps increase blood calcium levels by promoting calcium reabsorption and phosphate excretion in the kidneys. A: Inhibiting phosphate reabsorption helps prevent the formation of calcium phosphate crystals, maintaining the balance of calcium and phosphate in the blood.

Question 31

Flashcard Set: Proximal Convoluted Tubule (PCT) Function and Transport **Flashcard 1** **Q:** What percentage of water is reabsorbed in the proximal convoluted tubule (PCT)? **Flashcard 2** **Q:** How is sodium (Na+) reabsorbed in the PCT? **Flashcard 3** **Q:** What percentage of potassium (K+) is reabsorbed in the PCT? **Flashcard 4** **Q:** How is glucose reabsorbed in the PCT? --- **Flashcard 5** **Q:** What percentage of amino acids is reabsorbed in the PCT? --- **Flashcard 6** **Q:** What is the reabsorption percentage of chloride (Cl-) in the PCT? --- **Flashcard 7** **Q:** How is bicarbonate (HCO\(_3^-\)) reabsorbed in the PCT? --- **Flashcard 8** **Q:** What is the reabsorption rate of urea in the PCT? --- **Flashcard 9** **Q:** How are calcium (Ca\(^{2+}\)) and magnesium (Mg\(^{2+}\)) reabsorbed in the PCT? --- **Flashcard 10** **Q:** What is secreted into the urine from the PCT? --- **Flashcard 11** **Q:** How does secretion of H\(^+\) and NH\(_4^+\) in the PCT vary? --- **Flashcard 12** **Q:** What is the osmolality of the tubular fluid at the end of the PCT? ---

Answer 31

**A:** 65% of water is reabsorbed into the blood through osmosis. **A:** 65% of sodium is reabsorbed via sodium-potassium pumps, symporters, and antiporters. **A:** 65% of potassium is reabsorbed through diffusion. **A:** 65% of potassium is reabsorbed through diffusion. **A:** 100% of glucose is reabsorbed using symporters and facilitated diffusion. **A:** 100% of amino acids are reabsorbed using symporters and facilitated diffusion. **A:** 50% of chloride is reabsorbed through diffusion. **A:** 80-90% of bicarbonate is reabsorbed via facilitated diffusion. **A:** 50% of urea is reabsorbed via diffusion. **A:** Calcium and magnesium are reabsorbed at variable rates through diffusion. **A:** H\(^+\) (protons), NH\(_4^+\) (ammonium), urea, and a small amount of creatinine are secreted. **A:** Secretion of H\(^+\) and NH\(_4^+\) is variable and increases in acidosis via antiporters. **A:** The tubular fluid remains isotonic to blood at the end of the PCT, with an osmolality of 300 mOsm/L.

Question 32

Flashcard Set: Loop of Henle Function and Transport **Flashcard 1** **Q:** What percentage of water is reabsorbed in the descending limb of the Loop of Henle? **Flashcard 2** **Q:** How is sodium (Na\(^+\)) reabsorbed in the ascending limb of the Loop of Henle? **Flashcard 3** **Q:** What percentage of potassium (K\(^+\)) is reabsorbed in the ascending limb of the Loop of Henle? --- **Flashcard 4** **Q:** How is chloride (Cl\(^-\)) reabsorbed in the ascending limb of the Loop of Henle? --- **Flashcard 5** **Q:** What is the reabsorption rate of bicarbonate (HCO\(_3^-\)) in the Loop of Henle? --- **Flashcard 6** **Q:** How are calcium (Ca\(^{2+}\)) and magnesium (Mg\(^{2+}\)) reabsorbed in the Loop of Henle? --- **Flashcard 7** **Q:** What is secreted into the urine from the Loop of Henle? --- **Flashcard 8** **Q:** What is the osmolality of the tubular fluid at the end of the Loop of Henle? ---

Answer 32

**A:** 15% of water is reabsorbed via osmosis in the descending limb. **A:** 20-30% of sodium is reabsorbed using symporters in the ascending limb. **A:** 20-30% of potassium is reabsorbed through symporters in the ascending limb. **A:** 35% of chloride is reabsorbed through symporters in the ascending limb. **A:** 10-20% of bicarbonate is reabsorbed through facilitated diffusion. **A:** Calcium and magnesium are reabsorbed at variable rates through diffusion. **A:** Urea is secreted into the urine through recycling from the collecting duct. **A:** The tubular fluid is hypotonic at the end of the Loop of Henle, with an osmolality of 100-150 mOsm/L.

Question 33

Flashcard Set: Renal Corpuscle and Glomerular Filtration **Flashcard 1** **Q:** What is the typical glomerular filtration rate (GFR)? --- **Flashcard 2** **Q:** What substances are filtered in the renal corpuscle? --- **Flashcard 3** **Q:** What is the composition of the fluid at the renal corpuscle? --- **Flashcard 4** **Q:** Why are proteins not filtered in the renal corpuscle?

Answer 33

**A:** The typical GFR is 105-125 mL/min of fluid that is isotonic to blood. **A:** The renal corpuscle filters water and all solutes present in blood (except proteins), including ions, glucose, amino acids, creatinine, and uric acid. **A:** The fluid at the renal corpuscle is isotonic to blood, meaning it has the same concentration of solutes as plasma, excluding proteins. **A:** Proteins are typically too large to pass through the filtration membrane of the glomerulus, which prevents them from being filtered into the renal tubules

Question 34

Flashcard Set: Early Distal Convoluted Tubule Function and Transport **Flashcard 1** **Q:** What percentage of water is reabsorbed in the early distal convoluted tubule? --- **Flashcard 2** **Q:** How is sodium (Na\(^+\)) reabsorbed in the early distal convoluted tubule? --- **Flashcard 3** **Q:** What percentage of chloride (Cl\(^-\)) is reabsorbed in the early distal convoluted tubule? --- **Flashcard 4** **Q:** How is calcium (Ca\(^{2+}\)) reabsorbed in the early distal convoluted tubule? ---

Answer 34

**A:** 10-15% of water is reabsorbed via osmosis in the early distal convoluted tubule. **A:** 5% of sodium is reabsorbed via symporters in the early distal convoluted tubule. **A:** 5% of chloride is reabsorbed via symporters in the early distal convoluted tubule. **A:** Calcium reabsorption in the early distal convoluted tubule is variable and is stimulated by parathyroid hormone (PTH).

Question 35

Flashcard Set: Late Distal Convoluted Tubule and Collecting Duct Function and Transport **Flashcard 1** **Q:** What percentage of water is reabsorbed in the late distal convoluted tubule and collecting duct? --- **Flashcard 2** **Q:** How is sodium (Na\(^+\)) reabsorbed in the late distal convoluted tubule and collecting duct? --- **Flashcard 3** **Q:** How is bicarbonate (HCO\(_3^-\)) reabsorbed in the late distal convoluted tubule and collecting duct? --- **Flashcard 4** **Q:** How is urea handled in the late distal convoluted tubule and collecting duct? --- **Flashcard 5** **Q:** What is secreted into the urine from the late distal convoluted tubule and collecting duct? --- **Flashcard 6** **Q:** What determines whether the tubular fluid leaving the collecting duct is dilute or concentrated?

Answer 35

**A:** 5-9% of water is reabsorbed, with the insertion of water channels stimulated by ADH. **A:** 1-4% of sodium is reabsorbed through sodium-potassium pumps and sodium channels, stimulated by aldosterone. **A:** The reabsorption of bicarbonate is variable, depending on the secretion of H\(^+\) (via antiporters). **A:** Urea is reabsorbed in a variable amount, contributing to recycling back to the loop of Henle. **A:** Potassium (K\(^+\)) is secreted in variable amounts to adjust for dietary intake, and H\(^+\) is secreted in variable amounts to maintain acid-base homeostasis. **A:** The fluid is dilute when ADH levels are low and concentrated when ADH levels are high.