Cardiology 3: The Cardiac Cycle

Question 1

blood flow is determined by ____ difference across valves

Answer 1

pressure

Question 2

blood flows from an area of ___ pressure to an area of ___ pressure

Answer 2

high; low

Question 3

what is normal BP?

Answer 3

120/80

Question 4

in 120/80 mmHg, what is 120? what 80?

Answer 4

120 is peak BP; 80 is diastolic BP

Question 5

at end diastole, the pressure in the ventricles is what value?

Answer 5

almost zero

Question 6

at end diastole, the pressure is ____ in the atria compared to ventricle

Answer 6

higher

Question 7

during isovolumetric ventricular contraction, the AV valved are ___ and the aortic and pulmonary valves are __

Answer 7

closed; closed

Question 8

isovolumetric ventricular contraction starts at the end of ___

Answer 8

diastole

Question 9

during ventricular systole, does the ventricle or atria have higher pressure?

Answer 9

ventricle

Question 10

during ventricular systole, is the pressure higher in the ventricle or the pulmonary/aorta?

Answer 10

pulmonary artery and aorta

Question 11

during ventricular ejection, the AV valves are __ and the aortic/pulmonary valves are ___

Answer 11

closed; open

Question 12

during ventricular ejection, is the pressure higher in the ventricle or the arteries?

Answer 12

ventricle

Question 13

during isovolumetric ventricular relaxation, the AV valves are ___ and the pulmonary/aorta valves are ___

Answer 13

closed; closed

Question 14

during ventricular filling, the AV valves are ___ and the pulmonary / aorta valves are __

Answer 14

open; closed

Question 15

what is cardiac output?

Answer 15

volume of blood ejected from the heart per minute

Question 16

cardiac output may be varied by changes in what 2 things?

Answer 16

1. heart rate

2. stroke volume

Question 17

cardiac output is measured as what equation?

Answer 17

stroke volume x heart beat

Question 18

what is stroke volume?

Answer 18

amount of blood pushed out of the heart per contraction

Question 19

heart rate is determined by

Answer 19

rate of SA diastolic depolarization (pacemakeer electricla activity)

Question 20

stroke volume is determined by what 3 cardiac mechanical factors?

Answer 20

preload, afterload and contractility

Question 21

heart rate is regulated by the ____ nervous system

Answer 21

autonomic

Question 22

both divisions of the ANS influence SA node activity by altering rate of ____

Answer 22

diastolic depolarization

Question 23

parasympathetic stimulation has ___ latency and ___ decay which allows ___ control of function

Answer 23

short; rapid; beat-by-beat

Question 24

sympathetic stimulation is more ___ to act and decays ___

Answer 24

slow; gradually

Question 25

resting heart rate is primarily determined by what branch of the ANS?

Answer 25

parasympathetic

Question 26

which has stronger effect of heart rate, parasympathetic or sympathetic?

Answer 26

parasympathetic

Question 27

what is preload?

Answer 27

force that stretches relaxed muscle ( determines ventricular filling)

Question 28

what is afterload?

Answer 28

force against which muscle must contract (resistance to blood flow)

Question 29

what is contractility?

Answer 29

intrinsic ability of muscle to generate force at a given preload and afterload

Question 30

t/f afterload doesnt have an effect until the muscle is contracted

Answer 30

true

Question 31

Can more heart muscle be recruited to increase the force of contraction? Why/Why not?

Answer 31

all cardiac muscle contracts with every heartbeat, so there is nothing else to recruit, it all working all the time

Question 32

a change in force occurs by change in __

Answer 32

preload contractility

Question 33

increased preload is increased by increased ___ to the heart, which causes tissue ___, resulting in more actin-myosin interactions

Answer 33

return of blood; stretch

Question 34

with increased pre-load, actin-myosin interactions are increased by what 2 factors?

Answer 34

1. increased sensitivity to ca

2. decreasing inter-filament spacing

Question 35

does a stretched or shortened muscle create more force?

Answer 35

stretched

Question 36

increasing preload increases cardiac output by increasing stroke volume in an effect known as the ____

Answer 36

frank-starling mechanism

Question 37

sympathetic activity affects intracellular ___ dynamics and increases all of them

Answer 37

Ca

Question 38

sympathetic activity increases the __ and ___ of force generation (as well as rate of relaxation)

Answer 38

magnitude and rate

Question 39

t/f sympathetic activity also increases the rate of relaxation so heart is ready to regenerate force more quickly

Answer 39

true

Question 40

parasympathetic activation act by what NT at what receptors and what isthe effect?

Answer 40

ach; muscarinic; inhibit release of NE from neighbouring sympathetic nerve enedings