cardiovascular sensory regulation & control

Question 1

how is blood pressure and blood flow controlled

Answer 1

through interconnected neg feedback systems that work by adjusting HR, SV, systemic vascular resistance and blood volume

Question 2

do all feedback systems act at the same speed

Answer 2

no some act faster or slower

some are also shorter or longer than others

Question 3

where is the cardiovascular centre found

Answer 3

in the medulla oblongata

Question 4

what does the cardiovascular centre do

Answer 4

regulate HR and SV

controls neural, hormonal and local neg feedback systems that regulate blood pressure and blood flow to specific tissues

Question 5

what do groups of neurones in the CV centre do

Answer 5

regulate HR, contractility of ventricles and blood vessel diameter

Question 6

where are cardio-stimulatory and cardio-inhibitory centres found

Answer 6

in the CV centre

Question 7

what does vasomotor centre do

Answer 7

control blood vessel diameter

receives input from both higher brain region and sensory receptors

Question 8

3 main types of sensory receptors

Answer 8

proprioceptors

baroreceptors

chemoreceptors

Question 9

what do proprioceptors do

Answer 9

monitor movements of joints and muscles to provide input during physical activity

Question 10

what do baroreceptors do

Answer 10

monitor pressure changes and stretch in blood vessel walls

Question 11

what do chemoreceptors do

Answer 11

monitor concentration of various chemicals in the blood

Question 12

what does the output from CV travel along

Answer 12

neurons of ANS

Question 13

what does the sympathetic (stimulatory) system oppose

Answer 13

the parasympathetic system (inhibitory)

Question 14

what are baroreceptor reflexes and where are they found

Answer 14

pressure-sensitive receptors

found internal carotid arteries and other large arteries in neck and chest

Question 15

what does the carotid sinus reflex do

Answer 15

helps regulate blood pressure in brain

Question 16

what does the aortic reflex do

Answer 16

regulate systemic blood pressure

Question 17

what happens in baroreceptor reflexes when BP falls

Answer 17

baroreceptors stretched less which leads to slower rate of impulses to CV

Question 18

what does CV do once receiving signals from baroreceptor

Answer 18

decrease parasympathetic stimulation and increases sympathetic stimulation

Question 19

where are chemoreceptors found

Answer 19

close to baroreceptors of carotid sinus and aortic arch

Question 20

what do chemoreceptors do

Answer 20

detect
- hypoxia (low O2)
- hypercapnia (high CO2)
- acidosis (high H+)

and send signals to CV

Question 21

what does cv do after receiving signals from chemoreceptors

Answer 21

it increases sympathetic stimulation to arterioles and veins

produces vasoconstriction and an increase in BP

Question 22

what does martial natriutertic peptide (ANP) promote

Answer 22

natriuresis (loss of sodium)

Question 23

what does the atrial myocytes do

Answer 23

synthesise, store and release ANP in response to stretch

Question 24

what is the effect of natriuresis

Answer 24

renal vasodilation

increased blood flow= increased GFR

means more Na+ reaches macula densa meaning more Na+ secreted

Question 25

what can ANP inhibit

Answer 25

actions of renin and generally opposes effects of angiotensin II

Question 26

how does systemic control of arteriolar diameter occur

Answer 26

by sympathetic innervation

Question 27

how does tonic release or norepinephrine work
(systemic control of AD)

Answer 27

tonic release of norepinephrine binds of a-adrenergic receptors on vascular smooth muscle

helps maintain tone of arterioles

Question 28

what happens in sympathetic release of norepinephrine decreases

Answer 28

the arterioles dilate, if the release of norepinephrine increase, arterioles constrict

Question 29

how does local control of AD work

Answer 29

by paracrine factors
- vascular endothelium
- low O2 and high CO2
- active hyperaemia
- reactive hyperaemia

Question 30

what is the vascular endothelium sensitive to

Answer 30

pressure and flow

Question 31

what is the vascular endothelium the major determinant of

Answer 31

vascular resistance

Question 32

stages of active hyperaemia

Answer 32

1. increase of tissue metabolism
2. increase in release of metabolic
   vasodilators into EFC
3. arterioles dilate
4. decreased resistances creates increased blood flow
5. O2 and nutrient supply to tissue increases as long as metabolism is increased

Question 33

reactive hyperaemia stages

Answer 33

1. decreased tissue blood flow due to occlusion
2. metabolic vasodilators accumulate in EFC
3. arterioles dilate, but occlusion prevents blood flow
4. remove occulusion
5. decreased resistances creates increased blood flow
6. as vasodilators wash away, arterioles constrict and blood flow returns to normal