HR, SV & Q

Question 1

What is the HR at rest, submaximal and maximal exercise for an untrained person?

Answer 1

• Rest=70bpm
• sub-max=100bpm
• max=(220-age)bpm

Question 2

What are the values for SV for an untrained person at rest, sub-maximal and maximal exercise?

Answer 2

• rest=70ml
• sub-max=100ml
• Max=100ml (but decreases)

Question 3

What are the values of cardiac output for an untrained person at rest, sub-maximal and maximal exercise?

Answer 3

• rest=5L/m
• sub-max=10L/m
• max=20L/m

Question 4

What are the values of HR for a trained athlete at rest, sub-max and max exercise?

Answer 4

Rest=50bpm
Sub-max=120bpm
Max=(220-age)bpm

Question 5

What are the values of SV for a trained athlete at rest, sub-max and max exercise?

Answer 5

Rest=100ml
Sub-max=200ml
Max=200ml (but decreases)

Question 6

What is diastole and systole?

Answer 6

Diastole-relaxation phase of cardiac muscle:
•firstly atria, then ventricles
•blood is passively moving from left to right atrium and ventricles
•blood flows through bicuspid and tricuspid valves
•RA receives venous blood from superior and inferior vena cava
•LA receives oxygenated blood from lungs
Systole-contraction phase of cardiac muscle:
•firstly atria and ventricles
•aortic and pulmonary valves open to eject into aorta and pulmonary artery
•tricuspid and bicuspid valves are closed, so no blood enters ventricles
•blood continues to enter the atria through vena cava and pulmonary veins

Question 7

What happens to SV in maximal exercise?

Answer 7

Cardiovascular drift-the heart is pumping so fast it cannot keep up and fill back up with blood, so SV decreases

Question 8

What is starlings law of the heart?

Answer 8

SV depends on venous return
•during exercise SV increases therefore more blood enters the heart
•causes walls of heart chambers to stretch
-there are 2 stretches:
1.the atria-more blood enters atria = stretch of walls
Stimulates SA node causing increase in firing rate=increase HR
2.the ventricles-more blood enters = Stretch
-cause more forceful contraction of ventricular walls = increased SV

Question 9

Outline the redistribution of Q during exercise

Answer 9

• chemoreceptors, proprioceptors and baroreceptors
• receptors send info to the brain (vcc) which uses sympathetic nervous system to decrease the sympathetic stimulation to the arterioles and pre-capillary sphincter
• at muscles: decrease of sympathetic stimulation -> vasodilation (arteriole and sphincter widen) -> increased blood flow
• at organs: sympathetic stimulation increased -> Vasoconstriction (arteriole and sphincter narrow) -> decreased blood flow

Question 10

Outline the redistribution of Q during recovery

Answer 10

• chemoreceptors, baroreceptors and proprioceptors
• receptors send info to brain (vcc) which uses sympathetic nervous system to increase or decrease sympathetic stimulation of the arteriole and pre capillary sphincter
• at muscles: increase stimulation -> vasodilation of sphincter and arteriole (get narrow) decreases blood flow
• at organs: decrease stimulation -> vasodilation of sphincter and arteriole (get wider) increasing blood flow

Question 11

What is the effect of submaximal exercise on HR?

Answer 11

1) anticipatory rise due to adrenaline
2) rapid increase initially to cope with the increase of O2
3) reaches a Plato
4) (during recovery) there is a fast decrease
5) steady decrease

Question 12

What is the effect of maximal exercise on HR?

Answer 12

1) anticipatory rise due to adrenaline
2) fast increase initially
3) steady but still increasing
4) rapid decrease
5) steady decrease

Question 13

What is the effect of sub maximal and maximal exercise on stroke volume?

Answer 13

Sub maximal:
Rapid increase until reached a plato at 200ml
Maximal: decrease due to cardiovascular drift (the heart does not have enough time to refill with blood)

Question 14

What is the effect of sub maximal and maximal exercise on Q?

Answer 14

Sub max&max-steady increase then Plato