066 Renal control of electrolytes and acid base balance

Question 1

What is the normal concentration of plasma K+?

Answer 1

2-8mmol/L

Question 2

What may occur if K+ concentration is outside physiological standard conditions?

Answer 2

Cardiac arrhytmias

Question 3

Which channel regulates K+ secretion in the late distal tube and early collecting duct

Answer 3

ROMK channels in the principal cells.

Question 4

Which channel regulates K+ reabsorption in the late distal tube and early collecting duct

Answer 4

a intercalated cells through the H+/K+ antiporter

Question 5

How does aldosterone affect K+ concentrations?

Answer 5

It has an indirect effect by upregulating ENaC channels. The stronger depolarization caused by Na+ influx is balanced by more K+ secretions.

Question 6

How does tubular flow rate affect K+ secretion?

Answer 6

K+ is secreted down the concentration gradient into the tubule. Increasing flow rate reduces tendency for intratubular K+ to rise, so concentration gradient is maintained.

Question 7

Why does a plasma K+ after a K+ rich meal tend to be higher in people with diabetes mellitus?

Answer 7

Insulin stimulates the uptake of K+ ions into the cells.

Question 8

How do loop diuretics and thiazides increase K+ secretion?

Answer 8

By increasing tubular flow rate and sodium delivery to the distal tubule, it increases K+ secretion.

Question 9

How does exercise affect K+ concentration?

Answer 9

K+ ions are released from skeletal muscles, thus raising plasma K+.

Question 10

What is the normal concentration of plasma Ca2+?

Answer 10

2.5mmol/L

Question 11

What is the normal concentration of plasma HPO3- ?

Answer 11

1-2mmol/L

Question 12

What is the normal arterial plasma pH range?

Answer 12

7.35-7.45