cardiac cycle/dynamics and the conduction system

Question 1

what is stoke volume(SV)

Answer 1

The volume of blood ejected from the left ventricle per beat (ml)

Question 2

what is heart rate(HR)

Answer 2

The number of times the heart beats per minute (bpm)

Question 3

what is the average HR

Answer 3

72

Question 3

what is cardiac output (Q)

Answer 3

The volume of blood ejected (pumped) from the heart per minute (l/min)

Question 4

What is bradycardia

Answer 4

when your HR is under 60 bpm

Question 5

how do you calculate max HR

Answer 5

220-age

Question 6

what cause anticipatory rise

Answer 6

adrenaline

Question 7

what happens to HR during exercise

Answer 7

HR rises proportionately to exercise intensity
At submaximal levels HR will plateau when a steady state is reached and O2 demand is met.

Question 8

what happens to HR post exercise

Answer 8

nitial rapid drop in HR due to less oxygen demand
Then gradual drop to repay oxygen debt

Question 9

what is the resting SV

Answer 9

72ML

Question 10

if you are an elite performer how does SV change

Answer 10

it decreases

Question 11

what is starlings law

Answer 11

More blood to heart, leads to greater end diastolic volume
Greater stretch of atria walls lead to more forceful contraction

Question 12

what happens to stroke volume at maximal exercise

Answer 12

it decreases slightly due to reduced time to fill heart

Question 13

what is sub maximal exercise

Answer 13

exercise working between 40-60% of max HR

Question 14

what are the 2 reasons stroke volume increases

Answer 14

increased venous return
starlings law

Question 15

how to calculate stroke volume

Answer 15

SV=EDV-ESV

Question 16

What is Ejection Fraction

Answer 16

An ejection fraction of 60 % means that 60 % of the total amount of blood in the left ventricle is pushed out with each heartbeat.

Question 17

what SV percentage is right and what is too high

Answer 17

right=50-70%
too high=75%

Question 18

how to calculate cardiac output(Q)

Answer 18

HR x SV = Q

Question 19

what is the average Q at rest

Answer 19

5L

Question 20

What happens to Q during exercise

Answer 20

Cardiac output increases in line with exercise intensity
Plateaus during maximal exercise, due to inefficient diastolic filling time

Question 21

what happens to Q after exercise

Answer 21

In recovery there is a rapid decrease followed by a slower decrease to resting levels

Question 22

what is diastole

Answer 22

Diastole is the phase of the cardiac cycle that sees the heart relax and fill with blood.

Question 23

what is systole

Answer 23

The Systole phase is when the atria contracts, forcing blood into the ventricles

Question 24

how long in total does systole and diastole take

Answer 24

0.8s

Question 25

what happens in diastole

Answer 25

Oxygenated blood enters LA from pulmonary veins Rising pressure is Atria against AV valves forces blood into ventricles passively - right = tricuspid valve - left = bicuspid valve Volume of blood after filling stage is called END DIASTOLIC VOLUME (EDV)

Question 26

how long is diastole

Answer 26

0.4s

Question 27

how long is atrial systole

Answer 27

0.1s

Question 28

what happens in atrial systole

Answer 28

the atria contracts, forcing blood into the ventricles.

Question 29

how long is ventricular systole

Answer 29

0.3s

Question 30

what happens on the left side of ventricular systole

Answer 30

-The ventricles contract, increasing pressure closing the AV valves to prevent backflow into the atria -Increased blood pressure through ventricular contraction forces blood out of both ventricles (STROKE VOLUME) -Left ventricle forces blood through aortic valve into aorta (to body) -the valves remain shut and the aortic valves shut to prevent back flow

Question 31

what happens on the right side of ventricular systole

Answer 31

-The ventricles contract, increasing pressure closing the AV valves to prevent backflow into the atria -Increased blood pressure through ventricular contraction forces blood out of both ventricles (STROKE VOLUME) -right ventricle forces blood through pulmonary valve into pulmonary artery (to lungs) -the valves remain shut and the pulmonary valve close to prevent back flow

Question 32

what does myogenic mean

Answer 32

this means it generates its own impulse.

Question 33

what does cardiac impulse mean

Answer 33

The electrical impulse responsible for stimulating the heart

Question 34

what is the route of the conduction system

Answer 34

1.The Sino-atrial Node (SA node) located in the right atrium wall, emits an impulse and fires it through the atria walls, causing an impulse. 2.The impulse spreads to the adjacent interconnecting fibres of the left atrium 3.It moves to the specialised cells called atria-ventricular nodes (AV nodes) 4.AV Node acts as a distributor and passes the action potential (impulse) to the Bundle of His 5. It moves down the bundle of his to the apex of the heart 6.The impulse then spreads up the Purkinje Fibres (in the ventricle walls), causing excitation and ventricular systole (contraction)

Question 35

what is depolarisation

Answer 35

At every beat, the heart is depolarized to trigger its contraction

Question 36

What is the stroke volume of an untrained person at rest

Answer 36

60-90ml per beat

Question 37

What is the stroke volume of an trained person at rest

Answer 37

90-110ml per beat

Question 38

What is the stroke volume of an untrained person during sub-maximal exercise

Answer 38

120-140ml per beat

Question 39

What is the stroke volume of an trained person during sub-maximal exercise

Answer 39

160-200ml per beat

Question 40

what is venous return

Answer 40

the term used for the volume of blood that returns to the RIGHT side of the heart via the venules and veins.

Question 41

why is venous return needed

Answer 41

to assist the distribution of blood round the body

Question 42

what happens to Q and SV when venous decrease

Answer 42

they decrease

Question 43

what happens to Q and SV when venous increases

Answer 43

they increase

Question 44

How does an increase in Venous Return affect ventricular contraction?

Answer 44

Increase in blood to right atrium So, it stretches the (right atrium) chamber This increase the SA node firing rate …. So, HR increases

Question 45

what happens to venous return at rest

Answer 45

VR is sufficient to maintain SV and Q to meet demand for O2

Question 46

what happens to venous return during exercise

Answer 46

Blood pressure (BP) in the veins is too low to maintain VR, so SV and Q decrease

Question 47

what are the 5 mechanisms aiding venous return

Answer 47

Pocket Valves Muscle Pump Respiratory Pump Smooth Muscle Gravity

Question 48

what do pocket valves do

Answer 48

Pocket Valves prevent backflow of blood and direct it towards the heart.

Question 49

what do muscle pumps do

Answer 49

Veins are situated between skeletal muscles. When the muscles contract, this helps to push or squeeze blood back to the heart.

Question 50

what do respiratory pumps do

Answer 50

During exercise, breathing becomes deeper and faster. This causes pressure changes in the thorax and abdomen, squeezing large veins and thus blood back to the heart.

Question 51

what do smooth muscles do

Answer 51

Contraction and relaxation of smooth muscle in the middle layer of the vein walls helps push the blood towards the heart.

Question 52

what does gravity do

Answer 52

Blood from the upper body is aided by gravity

Question 53

what is blood pooling

Answer 53

VR requires a force to push the blood back towards the heart If there isn’t enough pressure, the blood will sit in the pocket valves of the veins.

Question 54

what are the impacts of vr on performance

Answer 54

more oxygen to working muscles less fatigue quick recovery