Cardiovascular Regulation Flashcards Preview

Cardiovascular Physiology HHP > Cardiovascular Regulation > Flashcards

Flashcards in Cardiovascular Regulation Deck (26)
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1
Q

which receptors are involved in MAP regulation

A

baroreceptors
cardiopulmonary stretch receptors
chemoreceptors

2
Q

what do baroreceptors detect

A

increase in bp

3
Q

where are the baroreceptors found

A

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

4
Q

which factors increase MAP

A

increase in CO

increase in SVR

5
Q

what does SVR stand for

A

systemic vascular resistance

6
Q

which factors increase SVR

A

length of blood vessels
viscous blood
vasoconstriction

7
Q

what is the effect of baroreceptors being stimulated at high bp

A

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)

8
Q

what is the effect of baroreceptors being stimulated at low bp

A

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

9
Q

what hormones causes vasoconstriction

A

adrenaline

10
Q

what hormones causes vasodilation

A

noradrenaline

nitric acid

11
Q

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

A
  • the latency of vagal bradycardia is short

- quick stimulation to sympathetic vasomotor nerve

12
Q

what is the biggest challenge to the CV system

A

orthostasis

13
Q

what is orthostasis

A

the effect of gravity on the distribution of VENOUS BLOOD

postural changes- bp drops all of a sudden

14
Q

what is cerebral perfusion

A

the pressure in brain

hypo-perfusion= low bp in brain

15
Q

how do the baroreceptors maintain normal cerebral perfusion

A

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

16
Q

what is cerebral ischemia

A

low blood flow to brain

17
Q

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

A

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

18
Q

what is Cushing’s reaction

A

when the chemoreceptors detect the cerebral ischemia and respond

19
Q

what do chemoreceptors detect

A

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

20
Q

where are the chemoreceptors located

A

close to baroreceptors (carotid sinus, aortic arch)

21
Q

effects of chemoreceptors

A
  1. cushings reaction (cerebral perfusion)
  2. sympathetic fibres= vasconstriction
  3. respiratory centre= increase rate/ depth of breathing= lung inflation reflex = increase HR
22
Q

what do chemoreceptors respond to

A

hypoxia
hypercamia
acidosis

23
Q

what do cardio-pulmonary stretch receptors detect

A

low(er) bp than baroreceptors

24
Q

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

A

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
25
Q

what does the release of ADH do

A

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

both increase blood volume

26
Q

how does the kidney maintain arterial pressure

A

controls blood volume via reinin- angiotensin-alodosterone system

NB. aldosterone is a hormone which increases blood volume