2

RENAL PHYSFOLOCY

MfrAngiotensin-Aldosterone System

SFmulation

4 Blcod pressure | Fluid volume f (J_rSympathetie

ł Kenin

f Va>oc3n«triction

l Angiotensm I

F

4 Angioiensin I

il * "fWO ^

reabsarption

*.:&n

vf5

Angiotensinogen

I

O \ •

Ł Va$otonsiiiction

♦ Aldo*eroiW!

Inhihitirn

f bload pressure | Fluid volur»e | (łfSympatbetir ANP

ACE

I NaCl-HjO reibsorplion

Mtcłnniirm nf Rrnin Rt leasc

Atterenl arterioU:

Etferer* arteriole

-ł»*A.CRA^w

Svmpalhetic nerze mecharism:

Pj -Adrenergir nerve; st mulat? renir reearn terom arrowsl

|uxtdgl:>merular HGlcetls

ftamrt-teplor mechanism:

va;ed pressure in afferent arterolf mliibils —'-m releisefrcm ;G cells (red arrowsl; dccteased • ssure pro-nołes renin relcase (greei arrowsl

CA/ćud#£.

^CIBM

Macula dcnsa mrchanism;

Inereascd NaCl in distal nephran inhibits r«nn release irec arrows); decreascd toad promotes renin release

Figi RE 6.12 Renin-Anciotensin-Aldosterone System

- ludoey synthesizes ondsecretesthe pioteolytic enzyne enin in ^ponsf to deereased lilood pressure .mc fltid .olunv? (upper Kenin release ult mately resuits m increased evels of ■tUKiiensin II (Alb and ddosterone, boh ot which stiu ulate NaCl 3Td water reabsoiption by thc ncphon i Ali actson the proxin»?l • ule and aldosterme acts on Ihe colK i ngdur.l). Ali is also a . tent vas«.onstrictor. This. when blood pressire and fluid volume

are Iow, the tenm-angiotonsin-aldosterore system ac:s to restr.re both. Therenin-secret ngjusiaglonemlar < dis are lorated aritnarily ki the aflerent arteriole (fowsr panel). Ihese cells espord dir«'tly tc changes in arterial pressure, alieraions in sympathet c ner\e ccti.ity and to the deliv?ry of NaCl :o the macula dema. Aht>revia6ons: AC i AngiotensirKonve'tir^» enzyme; A\’f: atrial natritretic peplide.

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