stroke volume

Question 1

adrenaline

Answer 1

stress hormone that is released by the sympathetic nerves and cardiac nerve during exercise which causes an increase in heart rate

Question 2

stroke volume

Answer 2

volume of blood pumped out by the heart ventricles in each contraction

Question 3

stroke volume depends on

Answer 3

venous return
- if venous return increases then stroke volume will also increase

the elasticity of cardiac fibres

• the more the cardiac fibres stretch, the greater the force of contraction will be.
• A greater force of contraction can increase the ejection fraction (starlings law)

the contractility of cardiac tissue (myocardium)

• the greater the contractility of cardiac tissue, the greater the force of contraction
• = increase in stroke volume and ejection fraction

Question 4

venonus return

Answer 4

volume of blood returning to the heart

Question 5

elasticity of cardiac fibres

Answer 5

the degree of stretch of cardiac tissue during the diastole phase of the cardiac cycle

Question 6

diastole phase

Answer 6

when the heart relaxes to fill with blood

Question 7

ejection fraction

Answer 7

the percentage of blood pumped out by the left ventricle per beat

amount of blood pumped out of ventricle / total amount of blood in ventricle

Question 8

starlings law

Answer 8

• > increased venous return
• > greater diastolic filling of heart
• > cardiac muscle stretched
• > more force of contraction
• > increased ejection fraction

Question 9

heart rate

Answer 9

the number of times the heart beats per minute

Question 10

cardiac output define

Answer 10

the volume of blood pumped out by the heart ventricles per minute

Question 11

cardiac output formula

Answer 11

stroke volume x heart rate

Question 12

max heart rate =

Answer 12

220 - age

Question 13

why does a trained performer have a greater heart rate range

Answer 13

because their resting heart rate is lower and their maximum heart rate increases

Question 14

what is anticipatory rise

Answer 14

a rise in heart rate before exercise due to the hormonal action of adrenaline which causes the SA node to increase heart rate

Question 15

cardiac hypertrophy

Answer 15

the thickening of the muscular wall of the heart so it becomes bigger and stronger

Question 16

explain the effects of cardiac hypertrophy

Answer 16

increased stroke volume as bigger heart enables more blood to be pumped out per beat (the end diastolic volume of the ventricle increases)

heart rate falls as the ventricle can contract with more force and thus push out more blood AKA bradycardia

this also causes oxygen delivery to muscles to improve as there is less oxygen needed for contractions of the heart

Question 17

bradycardia

Answer 17

a decrease in resting heart rate to below 60 beats per minute

Question 18

effect of cardiac output on exercise

Answer 18

• during exercise cardiac output increases due to an increase in heart rate and an increase in stroke volume
• cardiac output will increase as the intensity of exercise increases until maximum intensity is reached then it plateaus

Question 19

difference in cardiac output for a trained and untrained performer

Answer 19

at rest CO stays the same it is the max CO that changes
- during exercise the increase in max cardiac output will benefit the trained performer as they will be able to transport more blood to working muscles and therefore more oxygen.

Question 20

stroke volume in response to exercise

Answer 20

stroke volume increases as exercise intensity increases but at 40-60% of max effort stroke volume plateaus. This is because the increased heart rate near maximum effort results in a shorter diastolic phase (ventricles do not have as much time to fill up with blood, so they cannot pump as much out)