Regulation of Arteriole resistance Flashcards
Arteriole radius and what can be said to linked
mean arterial pressure
To keep the blood flow to each vascular bed sufficient, and keep mean arterial pressure in the right range, you have to engage in some resistance juggling.
How is this achieved
by 2 levels of control over the smooth muscle surrounding the arterioles
what are intrinsic mechanisms concerned with
meeting the selfish needs of each muscle tissue
what are extrinsic mechanisms concerned with
ensuring that total peripheral resistance of the whole body stays at the right level
describe extrinsic control by sympathetic nerves
Sympathetic nerves
release norepinephrine
binds to a1-receptors
causes arteriolar constriction
describe extrinsic control by parasympathetic nerves
usually no effect
describe extrinsic control by hormones
Epinephrine
released from adrenal medulla
binds to a1-receptors
causes arteriolar constriction
what other receptor can epinephrine activate in skeletal and cardiac muscle which in turn results in arteriole dilation
B2 receptors, therefore this will increase flow but decrease TPR
what is Angiotensin II produced in response to
low blood volume
what is the effect of Angiotensin II
causes arteriolar constriction
what type of hormone is vasopressin
an antidiuretic hormone
what is vasopressin produced in response to
low blood volume
what is the effect of vasopressin
causes arteriolar constriction
what are Atrial natriuretic peptide & Brain natriuretic peptide released in response to
in response to high blood volume
what are the effects of Atrial natriuretic peptide & Brain natriuretic peptide
cause arteriolar dilation
what is active (metabolic) hyperaemia
Active hyperemia is the increase in organ blood flow (hyperemia) that is associated with increased metabolic activity of an organ or tissue.
what is reactive hyperaemia
Reactive hyperemia is the transient increase in organ blood flow that occurs following a brief period of ischemia (e.g., arterial occlusion).
the coronary circulation shows what type of hyperaemia
active
in pulmonary circulation what happens to arterioles when O2 decreases and why
arteriolar constriction, this ensures that blood is directed to the best ventilated part of the lungs
there are “special areas” in relation to regulation of arteriolar resistance. These areas have specific properties that correlate with their function, what are these areas
cerebral circulation
renal circulation
pulmonary circulation
coronary circulation
what does epinephrine bind to
a1 receptors
what is the effect of epinephrine
causes arteriolar constriction
