4.1 Plasma Volume

Question 1

What does the volume of the extracellular fluid depend on?

Answer 1

Concentration of Na+

Question 2

How is Na+ reabsorption levels controlled?

Answer 2

Change osmotic pressure in peritubular capillaries

Question 3

What happens when the concentration of Na+ decreases?

Answer 3

Promote Na+ and water absorption

Question 4

What happens when the concentration of Na+ increases?

Answer 4

Inhibit Na+ and water absorption

Question 5

What is water reabsorption driven by in the PCT?

Answer 5

Osmotic gradient created by the solute absorption, hydrostatic force in the interstitium and the increased oncotic pressure in the peritubular capillary due to not filtering the proteins

Question 6

How much Na+ is reabsorbed in the PCT?

Answer 6

67% of the filtered load

Question 7

Why is it important to reabsorb a constant proportion of Na+ in the PCT?

Answer 7

Maintain osmotic gradient in capillaries

Question 8

What molecule is being reabsorbed in the descending loop of Henle?

Answer 8

Water only

Question 9

Describe the osmolarity of the fluid in the descending loop of henle

Answer 9

Hyperosmotic

Question 10

What substances are reabsorped in the ascending limb of the loop of Henle?

Answer 10

Na+ and Cl-

Impermeable to water

Question 11

How is the activity of the NaKCl2 pump maintained?

Answer 11

K+ is moved into the cell and then back into the lumen via ROMK

Question 12

What important ion is reabsorbed in the DCT only?

Answer 12

Ca2+

Question 13

What is the function of a priciple cell?

Answer 13

Reabsorbs Na+ wia ENaC

Question 14

What is the function of a Tyoe B intercalated cell?

Answer 14

Reabsorption of Cl-

Secretion of H+ or HCO3-

Question 15

What is natriuresis?

Answer 15

Reabsorption of Na+