Lecture 17: Baroreceptors and Regulation of Arterial BP Flashcards
where can carotid baroreceptors be found?
carotid arteries and aortic arch
what are baroreceptors
stretch receptors that respond to pressure changes
What is ANP and what does it do
Atrial Natriuretic Peptide
released by the atria in response to increased blood volume
- targets the kidneys and decreases Na+ reabsorption
- more Na+ leaving body = more H20 exiting which reduces blood volume & therefore BP
-ANP promotes vasodilation
-ANP inhibits renin release
how does the body respond to hypovolemic states (fluid loss)
↓ blood volume causes ↓ in arterial pressure and ↓ in baroreceptor firing
↑ in thirst, ↑ in ADH release
ADH increases kidney’s ability to reabsorb H20
ADH also causes vasoconstriction
↑ renin secretion (caused by sympathetic activity ti the kidneys)
how does the body respond to hypervolemic states
↑ bp leads to activation of stretch receptors in atria
ANP ↑
renin ↑, vasodilation ↑
bp decreases —> (-) feedback on baroreceptors
where are alpha 1 and alpha 2 receptors found?
cell membranes of smooth muscle cells in all arterioles and veins of abdominal organs
what are alpha 1 and alpha 2 receptors innervated by?
postganglionic sympathetic neurons (release NE)
what are the effects of NE on alpha receptors?
NE causes an increase of alpha receptors –>
- vasoconstriction
↑TPR
↑ arterial BP
where are Beta receptors found?
on arterioles in coronary circulation and skeletal muscle cells
what is renin and what does it do
an enzyme made by the kidneys
released when blood pressure decreases
what does ADH (vasopressin) do
ADH increases the ability of the kidney to reabsorb water
also causes vasoconstriction
serves to increase arterial blood volume and blood pressure
what are atrial receptor reflexes?
stretch-activated receptors in the L and R atria and pulmonary veins that respond to changes in volume
what does an increased volume in the LA & RA result in
↑ AP in atrial receptors which ↑ ANP which results in vasodilation and inhibition of renin release
what does a decreased volume in the LA & RA result in?
decreased amount of APs in atrial receptors
an increase in thirst
increased ADH
stimulates renin release
what is the main regulator of arterial BP
carotid baroreceptors
