S2W4 L1- Circulatory Physiology- Regulation of MAP- Al Benson

Question 1

Mean arterial pressure

Answer 1

CO x total peripheral resistance

Question 2

two factors that increase CO

Answer 2

increased SV
increased HR

Question 3

two factors which increase HR

Answer 3

decreased parasymp impulses

increased symp impulses and adrenal medulla hormones

Question 4

two factors which increase SV

Answer 4

increased symp impulses and adrenal medulla hormones

increased venous return

Question 5

4 factors which increase venous return

Answer 5

increase blood vol
skeletal muscle pump
resp pump
vasoconstriction

Question 6

3 factors which increase systemic vascular resistance

Answer 6

increased blood viscosity
increased total blood vessel length
decreased blood vessel radius

Question 7

a factor which increases total blood vessel length

Answer 7

increased body size- obesity

Question 8

a factor which increases blood viscosity

Answer 8

polycythaemia- increased number of rbc

Question 9

where is the CV centre located

Answer 9

medulla oblongata

Question 10

what are the CV centre inputs

Answer 10

higher brain centres
( cerebral cortex, limbic system, hypothalamus)
proprioceptors
baroreceptors
chemoreceptors

Question 11

what are the CV centre outputs

Answer 11

vagus nerve -> heart

cardiac accelerator nerve->
heart

vasomotor nerves -> blood vessels

Question 12

effect of increased frequency of impulses from vagus nerve to heart

Answer 12

decreased HR

Question 13

effect of increased frequency of impulses from cardiac accelerator nerve to heart

Answer 13

increase HR and contractility

Question 14

effect of increased frequency of impulses from vasomotor nerve to blood vessels

Answer 14

vasoconstriction

Question 15

how are baroreceptors excited

Answer 15

increased atrial pressure, increased distending pressure on atrial wall, increased stretch

Question 16

where are baroreceptors located

Answer 16

adeventitial layer of arterial walls in carotid sinus and aortic arch

Question 17

what afferent projections do barorrecptors have and where to

Answer 17

IX and X cranial nerves projections to CV centre

Question 18

what is the response when baroreceptors are activated

Answer 18

increase in MAP, increase parasymp stim of afferent, decrease symp stim of afferent, decrease SA node rate of firing, decrease ventricular myocardial contraction

Question 19

what is baroreflex an example of

Answer 19

negative homeostasis feedback loop

Question 20

respone of orthostasis

Answer 20

decrease MAP, decrease baroreceptor stim,
CV centre decreases vagal outflow to heart and increases symp outflow in cardiac and vasomotor nerves

Question 21

what is cerebral perfusion

Answer 21

delivery of blood to neural tissue in brain

Question 22

first response of orthostasis

Answer 22

MAP decreases. baroreceptor stimulation decreases

Question 23

why does baroreceptor stimulation decrease during orthostasis

Answer 23

decreased pulse pressure and decreased carotid sinus pressure (gravity)

Question 24

what is the response of the CV centre when orthostasis causes decreases baroreceptor stimulation

Answer 24

decreases vagal outflow to heart and increases sympathetic outflow in cardiac and vasomotor nerves

Question 25

what is the result of the CV centre responses to orthostasis

Answer 25

increase in HR, increase cardiac contractility, limiting fall in cardiac output by 20%, TPR increases by 30-40%, overall MAP increases 10-15mmHg above supine level

Question 26

what is responsible for the long term regulation of MAP

Answer 26

cardiopulmonary stretch receptors and hormonal influences

Question 27

two types of cardiopulmonary stretch receptors

Answer 27

atrial and pulmonary stretch receptors

Question 28

difference between atrial baroreceptors and cardiopulmonary stretch receptors

Answer 28

cardiopulmonary receptors respond to lower pressures

Question 29

primary role of cardiopulmonary stretch receptors

Answer 29

regulate blood volume

Question 30

when stimulation of cardiopulmonary stretch receptors is decreased, what is initiated

Answer 30

reflex release of antidiuretic hormone (e.g ADH & vasopressin) from hypothalamus

Question 31

two ways which ADH increase blood volume

Answer 31

increases reabsorption of fluid from renal tubules reduces rate of glomerular filtration by constricting afferent renal arteries

Question 32

another effect of ADH

Answer 32

vasoconstrictor effect particularly in splanchnic circulation increasing TPR

Question 33

where are chemoreceptors located

Answer 33

carotid aortic bodies

Question 34

3 things that stimulate chemoreceptors

Answer 34

hypoxia hypercaprea acidosis

Question 35

what does stimualtion of chemoreceptos lead to

Answer 35

sympathetically mediated peripheral vasoconstriction

Question 36

overall effect of chemorecpetors

Answer 36

increase CO2 increase TPR increase MAP

Question 37

what is the most important long term determinant of BP

Answer 37

blood volume

Question 38

what cells in the kidney detect low blood volume or low renal blood flow

Answer 38

juxtaglomerular cells

Question 39

what is released when juxtoglomerular cells detect low BV and low renal blood flow

Answer 39

renin enzyme

Question 40

action of renin enzyme

Answer 40

angiotensinogen-> angiotensin I

Question 41

three actions of angiotensin II

Answer 41

increase thirst vasoconstriction adrenal gland releases abosterone

Question 42

action of abosterone on kidney

Answer 42

salt/ water retention causes BP to rise

Question 43

what NS is the adrenal medulla an extension of

Answer 43

the sympathetic NS

Question 44

when is adrenaline and noradrenaline released

Answer 44

in response to stimulation of sympathetic preganglionic fibres

Question 45

effects of adrenaline

Answer 45

increase CO mediated by B adrenoceptors causing increase in MAP

Question 46

effect of noradrenaline

Answer 46

vasoconstriction via alpha receptors, increased total peripheral resistance

Question 47

Atrial Natiueretic Peptide (ANP) action

Answer 47

vasodilation promotes Na+ excretion in kidneys reduces MAP

Question 48

NO action

Answer 48

causes local vasodilation