RAAS Flashcards
What is the juxtaglomerular apparatus
3 major components:
1_ Macula Densa (DCT) blood comes through the afferent arteriole and coming out of the page is the DCT, detects the Na+ concentration. If the Na is low, low blood volume, then increase blood volume.
2_ JG Cells primary cells, release renin (granular cells)
3_ Mesangium cells:
What is the function of Renin?
Renin works on Angiontensinogen. ACE and stimulates SNS through B1 receptors
Angiotensin I converted to AT II (by ACE) in the lungs
Where would you find higher levels of ATII, in the pulmonary artery or pulmonary vein?
Pulmonary Vein.
Pulmonary artery = deoxygenated and therefore blood bringing ATI in.
What are the effects of ATII?
1) Increase in vasoconstriction, increase in DBP- at the levels of arterioles.
2) Increase in NE release and availability (B1 effects, stimulate JGA, alpha 1- vasoconstriction)
increase sodium reabsorption and blood volume (increase preload). Na gets reabsorbed into the blood from the tubular fluid, at the expense of K+ (K+ gets kicked out into the tubular fluid)
3) stimulates aldosterone release from zona glomerulosa (adrenal gland: GFR salt, sugar, sex hormones)
4) stimulates vasopressin (ADH) from posterior pituitary
5) constrict the efferent arteriole, less flow out- Increase the GFR, increase the amount of Na, and decrease the RAAS
What happens if you increase the radius of the afferent arteriole?
increase GFR, increase in NA, decrease RAAS
What happens if you decrease the radius of the AA?
Decrease GFR, decrease Na, increase RAAS
If creatinine is filtered at glomerulus- and GFR is low- then what happens to the creatinine concentration?
Decrease GFR, increase in Creatinine.
What dilates the afferent arteriole?
prostoglandins
What is the effect of NSAIDS on AA?
decrease the radius of AA, and therefore decrease GFR
What are the natiruetic peptides and their function?
ANP, BNP = decrease blood pressure. decrease preload- increase vasodilation (increase cgmp) and increase diuresis, decrease TPR
stimulus for natriuretic peptides
increase in atrial ventricular pressures
moa of ace inhibitors
inhibition of ACE, increase angiotensin I and renin, decrease angiotensin II
moa of ARBs (sartans)
receptor blockade of angiotensin II type I receptor
ATII level with ACE inhibitors
low
ATII levels with ARBS
normal/high