Cardiovascular Regulation

Question 1

which receptors are involved in MAP regulation

Answer 1

baroreceptors
cardiopulmonary stretch receptors
chemoreceptors

Question 2

what do baroreceptors detect

Answer 2

increase in bp

Question 3

where are the baroreceptors found

Answer 3

outer layer of the arterial walls in the carotid sinu and aortic arch

Question 4

which factors increase MAP

Answer 4

increase in CO

increase in SVR

Question 5

what does SVR stand for

Answer 5

systemic vascular resistance

Question 6

which factors increase SVR

Answer 6

length of blood vessels
viscous blood
vasoconstriction

Question 7

what is the effect of baroreceptors being stimulated at high bp

Answer 7

high MAP= baroreceptors detect stretch, stimulate the afferent nerves project in cranial nerves 9/10 going to the medulla oblongata= increase in efferent parasympathetic stimulation of heart= bradycardia (slow HR)

Question 8

what is the effect of baroreceptors being stimulated at low bp

Answer 8

low MAP= baroreceptors detect no stretch= increase in sympathetic stimulation of heart (increase CO) increase in adrenaline (vasoconstriction)

Question 9

what hormones causes vasoconstriction

Answer 9

adrenaline

Question 10

what hormones causes vasodilation

Answer 10

noradrenaline

nitric acid

Question 11

why is the baroreceptor a rapid acute buffer in homeostasis of MAP

Answer 11

• the latency of vagal bradycardia is short

- quick stimulation to sympathetic vasomotor nerve

Question 12

what is the biggest challenge to the CV system

Answer 12

orthostasis

Question 13

what is orthostasis

Answer 13

the effect of gravity on the distribution of VENOUS BLOOD

postural changes- bp drops all of a sudden

Question 14

what is cerebral perfusion

Answer 14

the pressure in brain

hypo-perfusion= low bp in brain

Question 15

how do the baroreceptors maintain normal cerebral perfusion

Answer 15

barorecptors in the carotid sinus detect the low bp= reduce the vagal outflow to the heart, and increase the outflow in sympathetic cardiac and vasomotor nerves

Question 16

what is cerebral ischemia

Answer 16

low blood flow to brain

Question 17

how do the chemoreceptors prevent cerebral ischamia thus maintain normal cerebral perfusion

Answer 17

low blood flow to brain= co2 accumulates and pH decreases= detected by chemoreceptors= increase in sympathetic outflow and more vasoconstriction= blood directed to brain

Question 18

what is Cushing’s reaction

Answer 18

when the chemoreceptors detect the cerebral ischemia and respond

Question 19

what do chemoreceptors detect

Answer 19

the changes in chemical composition of arterial blood: H+, CO2, h20

Question 20

where are the chemoreceptors located

Answer 20

close to baroreceptors (carotid sinus, aortic arch)

Question 21

effects of chemoreceptors

Answer 21

1. cushings reaction (cerebral perfusion)
2. sympathetic fibres= vasconstriction
3. respiratory centre= increase rate/ depth of breathing= lung inflation reflex = increase HR

Question 22

what do chemoreceptors respond to

Answer 22

hypoxia
hypercamia
acidosis

Question 23

what do cardio-pulmonary stretch receptors detect

Answer 23

low(er) bp than baroreceptors

Question 24

what is the effect of cardio-pulmonary stretch receptors at low bp

Answer 24

to increase the blood volume and reduce fluid loss via..

1. release of anti-diuretic hormone, ADH
2. constriction of renal arterioles (kidney/gut)= decrease rate of glomerular filtration

Question 25

what does the release of ADH do

Answer 25

ADH= increases reabsorption of fluid from renal tubules
= produces concentrated urine

both increase blood volume

Question 26

how does the kidney maintain arterial pressure

Answer 26

controls blood volume via reinin- angiotensin-alodosterone system

NB. aldosterone is a hormone which increases blood volume