Renal concentrating mechanisms Flashcards
Where is the site of renin synthesis?
The juxtaglomerular apparatus.
What are the four components of the JGA?
- modified smooth muslce cells in afferent arteriole.
- Modified smooth muscle cells in the efferent arteriole.
- Extraglomerular mesangial cells
- Macula densa cells in the distal tubule
What causes angiotensiongen to be cleaved to angiotensin I?
Renin
What converts Angiotensin I to angiotensin II?
Angiotensin Converting Enzyme
What is the more potent vasoconstrictor in the body?
Angiotensin II
Where is angiotensin I converted to angiotensin II?
Lungs
What are the 5 actions of Angiotensin II?
- Vasoconstriction and increased blood pressure.
- Increased aldosterone synthesis and release
- Increased ADH
- Increased thirst
- Feedback inhibition of renin release
What does ACE inhibitor do?
Inhibits angiotensin I from converting to angiotensin II?
What helps maintain GFR in spite of constrictive effects of Angiotensin II?
Prostagladins
Where is aldosterone synthesized in the body?
Zona glomerulosa of the adrenal cortex
Chronic ACE inhibitors cause a patient to be refractory to what medications?
Epinephrine and neosynephrine and ephedrine
What medication would you use to ACE inhibitor caused refractory hypotension?
Vasopressin
What causes aldosterone release and synthesis?
- Increased K+ levels in the ECF
- Angiotensin II
- Decreased Na+ levels
Where does aldosterone act on in the nephron?
Distal tubule and collecting ducts
What is the net effect of aldosterone?
Get rid of K+ and H+
Name a steroid hormone that is synthesized in the zona glomerulosa of the adrenal cortex?
Aldosterone
Does aldosterone cause a marked reabsorption of secretion of Na+?
Reabsorption
What is exchanged for K+ and H+ by aldosterone?
Na+
Where is ADH made?
Hypothalamus
Where is ADH released from?
Pituitary gland
Atrial natriuretic peptide does what to the nephron?
- Increases GFR
- Decrease Na+ reabsorption
- Inhibits release of renin/aldosterone/ADH
What is Conn’s Syndrome?
Aldosterone secreting tumor