19 Flashcards
what makes up the juxtaglomerular apparatus
afferent arteriole
efferent arteriole
distal tubule
where are macula dense cells found
in distal tubule
what senses the sodium changes in plasma
sodium sensors on macula dense cells on distal convoluted tubule
where are the juxtaglomerular cells found
end of afferent arteriole
what happens when sodium is low so bp is low
MACULA DENSA CELLS
- releases hormone to relax smooth muscle of AFFERENT ARTERIOLE
increase in GFR because increases pressure in glomerular capillaries - signal to juxtaglomerular cells to release renin in blood. so raise BP
how does renin get released and why
if low sodium sensed by macula dense cells.
by sympathetic activation because it has beta receptor on juxtaglomerular cells.
how is GFR control
autoregulated by local tubuloglomerular feedback ,
where does aldosterone get released from
correct of adrenal gland
and vascular smooth muscle.
where does aldosterone work on
on Enac channel proteins that pump sodium from the fluid to the blood on the DCT and CD
how does urine get more concentrated in the DCT and CD
because aldosterone stimulates ENAC cells to increase reabsorption of sodium. so increase water reabsorption so increase in volume of blood.
what kind of feedback is the RAAS system
negative
why does the RAA system cause vasoconstriction
to prevent hyponatremia
what cells release renin
juxtaglomerular cells
what happen if afferent arterioles are narrowed due to atheroma formation
GFR will be reduced so more sodium will be absorbed in the proximal tubule. so less will be in distal. so juxtaglim will release renin which will increase BP so chronic hypertension and excess body water and salt.
aldosterone release as a results of high renin will mean the person will retain a lot of water and salt.
what drugs can be used to reduce hypertension caused by too much renin
ACE inhibitor (captopril) angiotensin receptor antagonists (losartan)
Or diuretics thiazide derivatives (bendro) aldosterone antagonist (spironolacon= loop diuresis
