Ion balance: Na+

Question 1

What is the hormone for sodium reabsorption?

Answer 1

Aldosterone
1. released by adrenal cortex
2. Target P cells
3. Active reabsorb Na+ (secrete K+) -also regulates K+ bc of Na+/K+ pump

Question 2

The renin-angiotensin system (RAS)

Answer 2

1. blood pressure decreases
2. granular cells produce renin
3. Renin’s job is to turn angiotensinogen to ANGI
4. ACE enzyme easily turns it into ANGII
5. ANGII can increase sympathetic response, can also trigger release of vasopressin
6. Causes vasoconstriction, increases cardiovascular response, increases vasopressin, increases thirst, increases Na+ reabsorption (increased aldosterone).

->all of step 6 leads to increased blood pressure

Question 3

Atrial Natriuretic Peptide (ANP)

Answer 3

-lower blood volume by turning blood into urine
-produced by myocardial cells in the atria
-uses cGMP as second messenger
-trigger: increased blood volume
-Functions:
1. promotes excretion of sodium and water
2. suppress AVP, renin, and aldosterone