Water Absorption in Distal Tubule

What is the primary function of aldosterone in the renin-angiotensin-aldosterone pathway?

Stimulating vasodilation
Inhibiting renin release
Promoting sodium and water reabsorption (correct)
Decrease blood pressure

What is the effect of caffeine on sodium reabsorption in the nephron?

Increases sodium reabsorption
Regulates potassium secretion
Decreases sodium reabsorption (correct)
Has no effect on sodium reabsorption

What is the primary mechanism of water reabsorption in the collecting duct?

simple diffusion
active transport
osmotic gradient (correct)
facilitated diffusion

What is the role of aquaporin 2 in the collecting duct?

Facilitates water reabsorption (B) Signup and view all the answers

What is the effect of ADH on water reabsorption in the collecting duct?

Increases water reabsorption (A) Signup and view all the answers

What is the primary stimulus for ADH release?

Increased blood osmolarity (A) Signup and view all the answers

What is the effect of aldosterone on the apical membrane of the collecting duct?

Increases the number of open Na+ and K+ channels (C) Signup and view all the answers

What is the role of the renin-angiotensin-aldosterone pathway in regulating blood pressure?

Increases blood pressure (D) Signup and view all the answers

What is the effect of sodium reabsorption on water reabsorption in the nephron?

Sodium reabsorption increases water reabsorption (B) Signup and view all the answers

What is the primary mechanism of renal water conservation?

Increased sodium reabsorption (B) Signup and view all the answers

What is the primary function of aquaporin 2 in the apical membrane of the collecting duct?

To allow for water reabsorption dependent on ADH (A) Signup and view all the answers

Which of the following is a characteristic of the epithelium in the distal tubule and collecting duct?

Permeable to water and does not contain Na+/K+/Cl- contransporters (B) Signup and view all the answers

What is the primary effect of ADH on the kidneys?

To increase the amount of water reabsorbed (C) Signup and view all the answers

What is the maximum osmolarity of urine that can be achieved in the kidney?

1400 mOsm (D) Signup and view all the answers

What is the primary stimulus for the release of ADH?

An increase in osmolarity of the extracellular fluid (A) Signup and view all the answers

What is the effect of ADH on the epithelium of the collecting duct?

It increases the permeability of the epithelium to water (D) Signup and view all the answers

What is the role of the countercurrent multiplier in the kidney?

To establish the osmotic gradient that allows for water reabsorption (C) Signup and view all the answers

What is the effect of a decrease in mean arterial pressure on ADH secretion?

It increases ADH secretion (B) Signup and view all the answers

What percentage of water is reabsorbed in the proximal tubule?

70% (A) Signup and view all the answers

What is the primary function of aquaporin 3 in the basolateral membrane?

To facilitate the transport of water back into the bloodstream (C) Signup and view all the answers

What is the primary function of aquaporins in the descending loop of Henle?

To make the epithelium permeable to water in response to the osmotic gradient (B) Signup and view all the answers

What is the result of the osmotic gradient in the descending loop of Henle?

Water moves out of the lumen, decreasing the osmolarity (C) Signup and view all the answers

What is the role of urea in the nephron?

To support the necessary osmotic gradient that allows for water movement to occur (B) Signup and view all the answers

What is the name of the capillaries surrounding the loop of Henle and nephrons?

Vasa recta (C) Signup and view all the answers

What is the direction of water movement in the ascending limb of the vasa recta?

Water moves into the capillaries from the interstitial fluid (A) Signup and view all the answers

What is the result of the lack of urea transporters in the ascending limb of the vasa recta?

The osmolarity of the ascending limb increases (D) Signup and view all the answers

What is the primary function of the loop of Henle?

To maintain the osmotic gradient necessary for water reabsorption (A) Signup and view all the answers

What is the role of ADH in the kidney?

To increase the permeability of the epithelium to water (C) Signup and view all the answers

What is the result of the osmotic gradient in the ascending loop of Henle?

Sodium ions move out of the lumen, decreasing the osmolarity (B) Signup and view all the answers

What is the primary function of the vasa recta in the kidney?

To allow for the exchange of solutes and water between the loop of Henle and the blood (A) Signup and view all the answers