Renal 2 Flashcards
what stimulates the release of renin from granular cells?
decrease in Na, blood vol, blood press, sympathetic stim
how does the RAAS system work?
renin released–>converts angioteninogen to ang I, ang I— ACE—> Ang II; ang II potent vasoconstrictor, and it stims release of aldosterone from adrenal cortex
purpose of aldosterone?
enhances Na reabsorption in distal tub, collecting duct, and prox tub
purpose of ANP?
increase in blood vol–>inhibits Na and H2O reabsorption; inhibits aldosterone and ADH secretion; relaxes mesangial glom cells
purpse of ang II?
vasoconstrictor; releases aldosterone from adrenal cortex; release vasopressin from PP
Efferent arterioles have a higher affinity for ANG II than afferent arterioles
ya; at low conc, increases GFR; and high conc, decreases
what is PGE2, effects?
prostaglandin E2–Minimal effect on GFR in healthy resting individual When under stress or dehydration, PGE2 is produced
by the kidneys
PGE2 reduces the vasoconstrictor effect in the afferent arterioles and enhances the renal blood blow
i.e.) it could prevent the onset of severe renal ischemia
Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, inhibit the synthesis of prostaglandins
how do ATP and adenosine affect GFR?
causes vasoconstriction of the afferent arteriole
Reduces the GFR
It stimulates calcium release in afferent arteriole
smooth muscle cells, leading to contraction
As part of the tubuloglomerular feedback mechanism
how is Na reabsorbed at prox tub?
with an Na-H exchanger–>important for HCO3 reabsorption
regulated Na reabs occurs in the distal tubule and collecting duct
ya
glucose reabs in prox tub
99%; actively transported across apical membrane via cotransport–>Na reabsorbed with it; either transported 1 to 1 in erly prox tub, or 2 to 1 (2 Na, 1 glu) in late–> is less glu in the prox tub to be transferred
how are aa reabs?
Na-dependent co-transporter and facilitated diff across apical membrane;
ADH under influence of aldosterone
ya
how are aquaporins inserted into distal and coll duct cells?
vasopressin binds to membrane receptor; creates cAMP which activates the cAMP second-messenger system–>increases transcritption of aquaporin-2 genes–>more aquaporins made to insert into membrane via exocytosis
how does alcohol prevent water reabs?
inhibits ADH/vasopressin–>no aqp2 inserted into membrane
