Renal Blood Flow and Glomerular Filtration

Question 1

Name the order and requirement for the glomerular filtration barrier

Answer 1

Capillary endothelium - 700 angstroms, prevents blood cells from passing
Basement membrane - prevents plasma proteins and negatively charged proteins from passing
Epithelium with podocytes - 400 angstroms, prevents smaller plasma proteins and negative charges from passing

Question 2

Changes to Kf (glomerular surface area)

Answer 2

Increases in Kf increase GFR (ex. glomerulonephritis)

Question 3

Angiotensin II:
Action on Vessels
Stimulus
Effect on GFR
Effect on RBF

Answer 3

Vasoconstrictor
Decreased BP
Decrease
Decrease

Question 4

Endothelin:
Action on Vessels
Stimulus
Effect on GFR
Effect on RBF

Answer 4

Vasoconstrictor
Increased vessel stretch, A-II, bradykinin, EPI, decreased BP
Decrease
Decrease

Question 5

Prostaglandins (E1, E2, I2):
Action on Vessels
Stimulus
Effect on GFR
Effect on RBF

Answer 5

Vasodilator
Decreased BP, shear stress, A-II
No change
Increase

Question 6

Nitric Oxide:
Action on Vessels
Stimulus
Effect on GFR
Effect on RBF

Answer 6

Vasodilator
Shear stress, histamine, bradykinin, ATP
Increase
Increase

Question 7

Bradykinin:
Action on Vessels
Stimulus
Effect on GFR
Effect on RBF

Answer 7

Vasodilator
Prostaglandins, ACE
Increase
Increase

Question 8

ANP:
Action on Vessels
Stimulus
Effect on GFR
Effect on RBF

Answer 8

Vasodilator
Increased BP
Minimal increase
No change

Question 9

Mineralocorticoid Excess Syndrome

Answer 9

Principal cells (Mineralcorticoid Receptors– aldosterone & Glucocorticoid Receptors– cortisol)

plasma concentrations of glucocorticoids>mineralcorticoids

Deficiency of 11B-HSD2!!!

Usually– 11B-HSD2 irreversibly converts cortisol to cortisone so the glucocorticoids have low affinity for receptors.

DEFICIENT= prevents metabolism of cortisol so MR (i.e. aldosterone) can be activated by glucocorticoids and this leads to increased Na+ retention, hypertension, and hypokalemia!

Question 10

hyperaldosteronism

Answer 10

too much aldosterone

1) Na+ retention (increases BP, edema)
2) hypokalemia
3) alkalosis

Question 11

hypokalemia

Question 12

Hyperkalemia

Answer 12

> 5.0 mEq/L

causes:

1) renal failure
2) hyperglycemia
3) ACE inhibitors
4) lactic acidosis

leads to:

• decreased mineralocorticoid activity
• decreased distal Na+ deliver
• reduced ENaC function
• acidosis