Kidney Function

Question 1

Where is the Na+K+ pump and what does it do

Answer 1

basolateral surface and facilitates in 65% of sodium reabsorption. Does so via secondary active transport

Question 2

What is the main function of the proximal convoluted tubule

Answer 2

70% of reabsorption occurs here.

Question 3

What type of epithelium is present in the PCT

Answer 3

cuboidal epithelium with microvilli to increase surface area

Question 4

What happens to sodium in the PCT

Answer 4

Na is pumped out via active transport

Question 5

What happens to glucose in the PCT

Answer 5

glucose is pumped out via the GLUT transporter by facilitated diffusion

Question 6

What happens to water in the PCT

Answer 6

water is pumped out via osmosis

Question 7

What is transport maximum

Answer 7

the amount of substances which can be reabsorbed into the blood stream. It is affected by the number of transport molecules which are available.

Question 8

What is the descending loop permeable to

Answer 8

permeable to water, not to solutes (water reabsorption is high)

Question 9

What is the filtrate like at the bottom of the descending loop

Answer 9

more concentrated

Question 10

What happens in the ascending loop of henle

Answer 10

solutes pumped out by active transport, it is water proof

Question 11

What happens to the concentration of filtrate in the ascending loop

Answer 11

the concentration begins to decrease

Question 12

What is the job of the distal convoluted tubule

Answer 12

Fine tuning - site of fluid volume and electrolyte regulation. Sodium and water reabsorption is hormonally regulated

Question 13

What does anti-diuretic hormone do

Answer 13

increase water reabsorption

Question 14

What does aldosterone do

Answer 14

increase sodium reabsorption

Question 15

what does atrial natriuretic hormone do

Answer 15

promote sodium secretion

Question 16

Describe the role of aldosterone in detail

Answer 16

aldosterone indirectly regulates water reabsorption by increasing sodium reabsorption. It acts on the distal and collecting tubules, allowing sodium to be reabsorbed. It works in concert with ADH to reabsorb water and produce concentrated urine.

Question 17

Describe the countercurrent exchange mechanism

Answer 17

The blood passes by the ALH first, and so the solutes which come out go into the blood supply. Therefore, the conc of blood increases as it goes down by the ALH. As the blood stream ascends past the DLH, the water is picked up by the blood so the conc decreases. Grabs solutes first then water.