Integration if the Cardiovascular Mechanisms

Question 1

What are the arteries

Answer 1

passage of blood from heart to tissues

Question 2

what are the arterioles

Answer 2

major resistance vessels

Question 3

what are capillaries

Answer 3

site of gas exchange of gas, nutrients and water between blood and tissues

Question 4

what are veins

Answer 4

capacitance vessels
passageways of blood from tissues to heart
contain most of blood volume under resting conditions

Question 5

what must venous return provide

Answer 5

heart with sufficient blood to pump

Question 6

Regulation of heart rate

Answer 6

autonomic nervous system

Question 7

regulation of stroke volume

Answer 7

pre-load

myocardial contractility

Question 8

cardiac output =

Answer 8

HR x SV

Question 9

mean arterial blood pressure =

Answer 9

CO x systemic vascular resistance (SVR)

Question 10

MAP =

Answer 10

DBP + 1/3 pulse pressure

Question 11

Main site of systemic vascular resistance

Answer 11

arterioles

Question 12

contraction of vascular smooth muscles =

Answer 12

vasoconstriction

increase SVR and MAP

Question 13

relaxation of vascular smooth muscle =

Answer 13

vasodilation

decrease SVR and MAP

Question 14

vascular smooth muscles are controlled by what type of mechanisms

Answer 14

extrinsic

intrinsic

Question 15

resistance to blood flow = directly proportional to

Answer 15

blood viscosity

length of blood vessels

Question 16

resistance to blood flow = indirectly proportional to

Answer 16

radius of blood vessel

Question 17

resistance to blood flow is mainly controlled by

Answer 17

vascular smooth muscles through changes in the radius of the arterioles

Question 18

what’s involved in extrinsic control of VSM

Answer 18

nerves and hormones

Question 19

explain nerves as an extrinsic control of vascular smooth muscle

Answer 19

B.P. regulation
Baroreceptor reflux
sympathetic nerves
neurotransmitter = noradrenaline acting on a receptors
vasomotor tone

Question 20

explain vasomotor tone

Answer 20

partially constricted at rest
caused by - tonic discharge of sympathetic nerves
releases - noradrenaline

Question 21

increased sympathetic tone will _______ vasomotor tone resulting in _____

Answer 21

increase

vasoconstriction

Question 22

explain hormones as an extrinsic control of vascular smooth muscle

Answer 22

adrenaline
acting on a receptor = vasoconstriction
B2 recepetor = vasodilation

Question 23

where are a receptors found

Answer 23

skin
gut
kidney arterioles

Question 24

where are B2 receptors found

Answer 24

cardiac

skelteal muscle

Question 25

name hormones which affect vascular smooth muscle

Answer 25

angiotensin 2 | antidiuretic hormone

Question 26

angiotensin 2 causes

Answer 26

vasoconstriction

Question 27

antidiuretic hormone causes

Answer 27

vasoconstriction

Question 28

what does intrinsic control of vacsuclar smooth muscle match

Answer 28

blood flow if different tissues to heir metabolic needs | chemical and physical factors

Question 29

chemical local metabolites

Answer 29

influence contraction

Question 30

list factors causing relaxation of arterial smooth muscles

Answer 30

``` decreased PO2 increased PCO2 increased H+ increase K+ increased osmolarity adenosine release ```

Question 31

relaxation of vascular smooth muscles results in

Answer 31

vasodilation | metabolic hyperaemia

Question 32

humoral agents cause vasodilation

Answer 32

histamine bradykinin nitric oxide

Question 33

key features of nitric oxide

Answer 33

continuously produced vascular endothelium potent vasodilator flow dependent - no formation receptor stimulated - no formation

Question 34

humoral agents causing vasoconstriction

Answer 34

serotonin thromboxane A2 leukotrienes endothelin (potent vasoconstrictor)

Question 35

explain endothelian

Answer 35

important in maintenance of vascular health | damage caused - high BP high cholesterol diabetes smoking

Question 36

endothelial produced vasodilator are -

Answer 36

anti-thrombotic anti-inflammatory anti-oxidants

Question 37

endothelial produced vasoconstrictors are

Answer 37

pro-thrombotic pro-inflammatory pro-oxidants

Question 38

physical intrinsic control of VSM

Answer 38

temp myogenic response sheer stress

Question 39

cold temp cuases

Answer 39

vasoconctstriction

Question 40

warm temp causes

Answer 40

vasodilation

Question 41

myogenic response explain

Answer 41

MAP rises - constrict | MAP falls - dilate

Question 42

myogenic response important in

Answer 42

brain | kidneys

Question 43

local control of SVR immediate or delayed

Answer 43

immediate | overrides nervous control

Question 44

list factors influencing incresedvenous return

Answer 44

increased venomotor tone increased skeletal muscle pump increased blood volume increased respiratory pump

Question 45

increased venous return leads to

Answer 45

increased arterial pressure increases EDV increased stroke volume

Question 46

increased venomotor tone leads to

Answer 46

increased venous return, SV and MAP

Question 47

venous smooth muscles are supplied by what

Answer 47

sympathetic nerve fibres

Question 48

stimulation of sympathetic nerve fibres

Answer 48

venous constriction - venous valves - blood driven to RA

Question 49

what increases venous return to the heart

Answer 49

increasing rate and depth of breathing | muscle activity

Question 50

acute CVS response to exercise

Answer 50

sympathetic increases HR, SV = CO increases vasomotor nerves = reduce flow to kidneys + gut (vasoconstriction) skeletal + cardiac muscle = vasodialtion blood flow to skeletal + cardiac muscle = increase increased CO = increased systolic BP decreased SVR decreased DBP

Question 51

explain how sympathetic stimulation increases heart rate

Answer 51

increases rate of firing of SA node decreases AV nodal delay (also increases force of contraction)

Question 52

sympathetic stimulation on pacemaker cells

Answer 52

slope increases potential reached quicker frequency increases positive chronotropic effect

Question 53

sympathetic nerve stimulation on ventricular contraction

Answer 53

contractility of heart given EDV rises | Frank-Starling curve to left

Question 54

chronic CVS response to exercise

Answer 54

regular - reduce B.P. multifactorial e.g. reduction in sympathetic tone and noradrenaline levels