Regulation of blood pressure and flow

Question 1

baroreceptors

Answer 1

detect changes in MAP and regular bp short term

Question 2

what regulates bp long term

Answer 2

kidneys

Question 3

location of baroreceptors

Answer 3

carotid sinuses and aortic arch

Question 4

what type of walls are they located in

Answer 4

thin walls that can be stretched by pressure

Question 5

how do they detect changes in pressure

Answer 5

baroreceptor nerve endings are sensitive to stretch and pressure

Question 6

rate of baroreceptor nerve firing proportional to

Answer 6

magnitude and changes in MAP

Question 7

are baroreceptors positive or negative feedback

Answer 7

negative

Question 8

where do baroreceptors signal to

Answer 8

medulla oblonglata

Question 9

medulla oblongata regulates

Answer 9

Heart rate
stroke volume
diameter

Question 10

which nervous system do baroreceptors mainly work with

Answer 10

autonomic

Question 11

sympathetic

Answer 11

incr MAP

Question 12

parasympathetic

Answer 12

decr MAP

Question 13

adrenaline

Answer 13

increase MAP

Question 14

angiotensin II and vasopressin

Answer 14

increase MAP

Question 15

how do symp nerves work

Answer 15

mediated by noradrenaline via B adrenergic receptors
a1 adrenergic receptors in arterioles ( except skeletal muscle which is a2 adrenergic)
increase cardiac output and peripheral resistance

Question 16

how do parasympathetic nerves work

Answer 16

mediated by ach by muscarinic receptors

inhibit heart rate

Question 17

causes of hypotension

Answer 17

loss of blood (hemorrhage)
loss of salts: burns and sweating, diarrhoea and vomiting
stress- fainting

Question 18

orthostasis

Answer 18

standing up

associated with a drop in mean blood pressure

Question 19

why does orthostasis occur and how does the cardiovascular system compensate?

Answer 19

standing and effect of gravity leads to blood pooling in legs

reduced blood vol and lowering of central venous pressure

reduced venous return, reduced end diastolic pressure, reduced SV and reduced blood pressure

baroreceptor reflex will compensate

Question 20

how do baroreceptor respond to lower arterial pressure

Answer 20

lower firing of baroreceptors

Question 21

local flow is regulated by what sorts of factors

Answer 21

local, neuronal, hormonal

Question 22

local factors which control arterioles dilation and constriction

Answer 22

myogenic response
metabolites
autocoids
endo cells

Question 23

myogenic response

Answer 23

vasoconstriction of arterioles caused by stretch of smooth muscle
brain, kidney heart

Question 24

vasodilation induces by metabolites

Answer 24

O2 decr
CO2 incr
H+, adenosine, K+, osmolarity incr

Question 25

autocoids

Answer 25

released as result of inflammation and bleeding
inflammation leads to vasodilation eg via histamine
bleeding leads to constriction

Question 26

endothelial cells

Answer 26

release local factors ( paracrine)
nitric oxide and prostacyclin- dilation
endothelin 1 - constriction

Question 27

incr metabolic activity leads to (local)

Answer 27

active hyperemia

Question 28

reduced blood flow in organ leads to (local)

Answer 28

flow auto regulation

Question 29

active hyperemia sequence

Answer 29

incr metabolic activity of organ
decr O2, incr metabolites in organ isf
arteriolar dilation in organ
incr blood flow to organ

Question 30

flow autoregulation sequence

Answer 30

decr arterial pressure in organ
decr blood flow to organ
decr O2, incr metabolites, decr vessel wall stretch in organ
arteriolar dilation in organ
restoration of blood flow towards normal in organ

Question 31

neural control of arterioles in skin

Answer 31

room temp: arterioles constricted by moderate symp activity

cold, fear or loss of blood: symp activity incr and arterioles vasoconstrict. divert blood to essential organs

incr body temp: symp activity decr and arterioles vasodilation
blood flow to skin incr to cool

Question 32

hormones involved in arterioles vasoconstriction and dilation

Answer 32

angiotensin II
vasopressin
atrial natriuretic peptide

Question 33

angiotensin II

Answer 33

vasoconstriction

renin- angiotensin system

Question 34

vasopressin

Answer 34

vasoconstriction

posterior pituitary gland

Question 35

atrial natriuretic peptide

Answer 35

vasodilation

cardiac atria

Question 36

a1 adrenergic receptors

Answer 36

cause vasoconstrict in response to noradrenaline and adrenaline

Question 37

B1 adrenergic receptors in skeletal muscle

Answer 37

cause vasodilation in response to adrenaline and noradrenaline

Question 38

i’m exercise you need to

Answer 38

boost O2 uptake and co2 removal ( incr Co)
increase blood flow to muscles, heart and skin (changes peripheral resistance)
stabilise arterial bp (despite changes in co and peripheral resistance)

Question 39

What is the first thing the brain does during exercise

Answer 39

switches off baroreceptors

resets upwards so they don’t have opposing effects

Question 40

blood flow during exercise

Answer 40

divert to muscles, skin and heart by vasodilation of arterioles
decr to essential organs by vasodilation of arterioles

Question 41

Symp and Parasymp output during exercise

Answer 41

Decr parasymp output to heart
incr symp output to heart
incr symp output to veins

Question 42

What happens to the CVS during exercise?

Answer 42

Slight drop in TPR
LArge incr CO
SO overall MAP incr

MAP = CO x TPR

CO incr a lot because HR and SV incr

Question 43

local responses during exercise

Answer 43

contraction skeletal muscle, leading to vasodilation of arterioles to skin and muscle

Question 44

Why does TPR decr

Answer 44

incr sympathetic and local responses lead to vasodilation of arterioles to skin and muscle
(see useful diagram)

Question 45

local control involves

Answer 45

vasoconstriction and vasodilation