L118: Kidney 1/2 Recap

Question 1

What is the function of the kidneys?

Answer 1

• Filter blood;

- Produce urine as a by-product.

Question 2

What is the functional unit of the kidneys?

Answer 2

Nephron

Question 3

In the kidneys, where does filtration of blood occur?

Answer 3

The renal corpuscle

Question 4

What are the major components of the renal corpuscle?

Answer 4

• Glomerulus;

- Bowman’s capsule.

Question 5

What are the major components of the filtration barrier?

Answer 5

• Fenestrated glomerular endothelium;
• Basement membrane;
• Pedicels of podocytes.

Question 6

What is GFR?

Answer 6

Glomerular Filtration Rate

Question 7

What is GFR equal to?

Answer 7

Kidney function (measured by the blood concentration of creatinine)

Question 8

How much filtrate do the kidneys filter in one day and how much is reabsorbed?

Answer 8

180L/day, 99% is reabsorbed

Question 9

In the kidneys, where does reabsorption and secretion occur?

Answer 9

The renal tubule

Question 10

What are the major components of the renal tubule?

Answer 10

• PCT;
• L of H;
• DCT;
• Collecting duct.

Question 11

Why is the PCT much longer than the DCT?

Answer 11

To ensure maximal reabsorption of nutrients

Question 12

What kind of epithelium surrounds the Bowman’s capsule (parietal layer)?

Answer 12

Simple, squamous

Question 13

What part of the L of H is freely permeable to water?

Answer 13

Thin, descending limb

Question 14

What part of the L of H is impermeable to water?

Answer 14

Thick, ascending limb

Question 15

What part of the L of H actively pumps ions (Na+, Cl- and K+) into the interstitium?

Answer 15

Thick, ascending limb

Question 16

What is the purpose of the thick, ascending limb generating a ‘salty’ interstitium?

Answer 16

To generate an osmotic gradient which facilitates water reabsorption from the thin, ascending limb

Question 17

In the kidneys, where does fine-tuning of filtrate occur?

Answer 17

DCT

Question 18

What is fine-tuning?

Answer 18

Site of fluid volume and electrolyte regulation

Question 19

How is sodium and water reabsorption regulated?

Answer 19

Hormones

Question 20

Give an example of a hormone that increases water reabsorption:

Answer 20

Anti-diuretic hormone (ADH)

Question 21

Give an example of a hormone that increases sodium reabsorption:

Answer 21

Aldosterone

Question 22

Give an example of a hormone that promotes sodium excretion:

Answer 22

Atrial natriuretic hormone (ANH)

Question 23

How does aldosterone promote sodium reabsorption?

Answer 23

Acts on distal and collecting duct to allow Na+ to be reabsorbed

Question 24

How does aldosterone promote sodium reabsorption?

Answer 24

• Acts on distal and collecting duct to allow Na+ to be reabsorbed;
• Works (distally) with ADH to reabsorb water;
• Collecting duct becomes permeable to water.

Question 25

Aldosterone acts to increase sodium reabsorption, how does this effect water regulation?

Answer 25

• Increases the concentration of sodium;
• Creates an osmotic gradient;
• Water follows and is reabsorbed.

(K+ concentrated urine)