8. Electrolyte Physiology DSA

Question 1

Where would paracellular movement of water be greater, in the small intestine or the large intestines?

Answer 1

In the small intestine.

The colon has “tight” tight junctions, and does not permit paracellular movement.

Question 2

The jejunum is the major site of absorption for what electrolyte?

Answer 2

Na+

Question 3

The enterocytes of the colon typically absorb what electrolyte, and secrete what other electrolyte?

Answer 3

The enterocytes of the colon typically secrete potassium and absorb sodium via the Na+/K+ channels.

Question 4

Overall, the jejunum absorbs what compound?

Answer 4

Sodium bicarbonate.

Question 5

Overall, the ileum absorbs what compound?

Answer 5

Sodium chloride.

Question 6

What two electrolytes are most often lost in severe diarrhea?

Answer 6

HCO3- / K+

Question 7

What acid-base disturbance can occur in patients with severe diarrhea?

Answer 7

Hyperchloremic metabolic acidosis with normal anion gap.

Question 8

What cells of the intestine secrete electrolytes and water, rather than absorb it?

Answer 8

Epithelial cells lining the intestinal crypts.

Question 9

How does cholera toxin cause water loss?

Answer 9

Enters an enterocyte, inhibits the GTPase of the Gs protein coupled to adenylyl cyclase, causes the GTP to not be converted to GDP, causing Cl- channels to stay open, causing water loss.

Question 10

With what are patients rehydrated after severe diarrhea?

Answer 10

Na+, Cl-, HCO3-, and glucose to stimulate the glucose-Na+ cotransporter.