Regulation of Arterial Pressure

Question 1

what is the equation for mean arterial pressure?

Answer 1

MAP = CO x TPR
CO = HR x SV
MABP = HR x SV x TPR
norm - 93.3
Map = (2/3)dbp + 1/3(sbp)

Question 2

Innervation for carotid sinus and aortic sinus?

sends to? what NT?

Answer 2

glossopharyngeal n (sinus n of hering)
vagus n or aortic n

nucleus tractus solitarius + hypothalamus -> efferents of ps/sym
glutamate

Question 3

baroreceptor reflex responses to?

Answer 3

change in arterial pressure (stretch)

and PO2, PCO2, pH

Question 4

what part of the brain participates in parasympathetic activity associated with CV fxn?

sympathetic

Answer 4

dorsal motor nucleus of the vagus, nucleus ambiguus

rostral ventrolateral medulla
sym have robust response

Question 5

how does sympathetics respond to hemmorage?

Answer 5

decreased MAP, baroreceptor firing rate

decrease in cardiac accelerator/vasconstrictors

actives symp by constricting arterioles/veins (alpha rec)

signaling to SA node to up HR and to increase contractility (B1 receptors)

fluid retention of kidney and renin secretion

(indirect - decrease in parasym activity, increase in TPR)

Question 6

what is the highest pressure the carotid bodies read?

lowest?

Answer 6

200 mmHg

40-60 mmHg (bottoms out, doesn’t fire anymore)

Question 7

what is the difference bw aortic and carotid?

Answer 7

aortic has a higher threshold for activation, responds above saturation, less sensitive to rate, less effect by decreases

carotids are most sensitive to flow because it protects the brain

Question 8

parasympathetic do what?

Answer 8

NTS ->

increase baroreceptor firing rate

decrease HR (vaugs to SA, muscarinic receptors)

stim NO release by AcH, indirectly calling vasodilation of bv

decrease in TPR and CO

Question 9

baroreceptor adaptations occur because?

Answer 9

high bp resets baroreceptors to reg pressure at higher set pt so the freq of AP is decreased to ‘normal’

Question 10

long term adjustments from the baroreceptor reflex?

Answer 10

renin-angiotensin II - aldosterone system
(atria to kidney by controling bp by reg blood volume an d TPR)
it releases angiotensin (min) -> anigotensin (hour) -> aldosterone (hour) for a week

hormonal system takes 48hr-1wk to kick in

Question 11

renin is activited by?

functions?

Answer 11

activated by b1 adrenergic and secreted by juxtaglomerular cells to low bp/sym stimulation

decreases nacl at macula densa
angiotensinogen -> angiotensin I (blood) -> at II (kidney/lung)

Question 12

angiotensin II does what

Answer 12

secretion of aldosterone from adrenal cortex (increases bv, preload/sv, co, bp)

increases na reabsorption

thirst

adh (vasopressin, fluid retention)

vasoconstriction of arterioles AT1 receptors (tpr and bp)

Question 13

adh (vasopressin) responses to

Answer 13

v1 recept (sm), v2 (collecting ducts)

angio II
atrial recept in low preload
up osmolality of blood
sympathetic ns activation

increase tpr and water retention

Question 14

natriuretic peptides?

Answer 14

atrial, brain, c-type

when there is lots of preload of atria/v, protect from overstretching

causes artery dilation, fluid loss, inhibits renin

Question 15

what happens to the vas function curve in times of hemorrhage, dehydration and loss of body fluids?

Answer 15

shifts left

from decrease bv, preload, sv, co, map

Question 16

what responses to hemorrhage?

Answer 16

decrease carotid sinus firing -> increase hr, contractility, co, decrease in unstressed vol -> increase tpr -> increase of epinephrine, adh, renin, ang Ii, aldosterone, decrease anp

Question 17

what happens when you exercise?

Answer 17

increase sym output - b1 rec, hr/contractility, venours return, arteriolar vasoconstriction due to a1 ->

constriction to skin, splanchnic regions, kidney, inactive m
vasodilation to active m and cornaries (local release, overcomes b2 bc dont want inc tpr)- release lactate, k, adenosine
pulse pressure, sbp increse, dbp not much
tpr reduces overall

Question 18

what causes venous pooling in LE? leads to?

Answer 18

edema or hypotension

no movement cause venous return to build in LE, increasing the venous and cap hydrostatic pressure

(dec in map, sv, co (from dec venous return), central venous pressure dec so blood pools)

activates baroreceptor and hormonal reflex

Question 19

if baroreceptor and hormonal reflex doesn’t compenstate quick, then what happens

Answer 19

orthostatic hypotension