regulation of stroke volume and heart rate

Question 1

regulation of heart rate

Answer 1

sympathetic and parasympathetic ( vagus)

Question 2

increase in heart rate by sympathetic

Answer 2

increasing the slope and decreasing the time between action potential

Question 3

target of sympathetic nervous system

Answer 3

produces noradrenaline and effects on the
adrenal medulla to produce adrenaline that acts on beta 1 receptors on the sinoatrial node

Question 4

parasympathetic effect on heart rate

Answer 4

decreases heart rate , production of acetylcholine which acts on muscarinic receptors of the sinoatrial node.

Question 5

decrease in the slope of action potential and hyper - polarisation of the action potential

Answer 5

decrease in heart rate

Question 6

regulation of stroke volume

Answer 6

factors that affect end diastolic volume
factors that affect end systolic volume

Question 7

preload

Answer 7

amount of blood present in the heart just before systole by passive filling

Question 8

how does preload influence stroke volume

Answer 8

energy of contraction will be equal to the initial length of the heart muscle

Question 9

factors that affect end diastolic volume

Answer 9

venous return
self regulation

Question 10

increased venous return effect on the end diastolic volume

Answer 10

there is increased end diastolic volume

Question 11

afterload

Answer 11

amount of blood during isovolumetric contraction ; the ;load at which the heart pumps against

Question 12

factors that affect after - load

Answer 12

theory of the 3 pipes

Question 13

factors that affect afterload

Answer 13

increase in resistance of the arterioles means there is pull of blood in the aorta which means there is alot pressure needed to just open the aortic valves , there is therefore less blood present to push the blood out of the heart hence lower stroke volume.

Question 14

neural regulation of stroke volume

Answer 14

sympathetic nerve system which causes release of noradrenaline and circulates adrenaline form the adrenal medulla.

Question 15

sympathetic effect on the myocytes( non pacemaker cells)

Answer 15

they bind on the beta 1 receptors of the myocytes which means they have a greater contractile effect

Question 16

parasympathetic effect on the vagus nerve

Answer 16

Little effect​

Probably because the vagus nerve does not innervate the ventricular muscle​

Question 17

summary of the regulation of stroke volume

Answer 17

preload
contractility
afterload

Question 18

control of cardiac output

Answer 18

factors that affect stroke volume
factors that affect heart rate

Question 19

causes of reduced total peripheral resistance

Answer 19

arteriolar dilation in the muscles
reduces afterload