Download Response of the Cardiovascular System: Question and Answer Page

Unit 3 part II Response of the Cardiovascular (Vascular) system to physical activity
3.II
1.
Vascular Part II questions / answers
After the final whistle, it is recommended that players complete a cool down. Describe the
physiological benefits of an active cool down.
[5]
(submax 5 marks)
(an active cool down:)
1.
reduces the risk of injury
2.
reduces the possibility of DOMS/delayed onset of muscle soreness
3.
(keeps metabolic activity levels elevated) which gradually decreases HR / RR
4.
maintains respiratory pump
5.
maintains muscle pump
6.
to prevent blood pooling in the veins/enhance venous return
7.
which maintains SV/Starling’s law of the heart
8.
keeps capillaries dilated to flush muscles with oxygenated blood/remove lactic acid
CO2
2.
Describe the changes that occur in the distribution of cardiac output as a performer moves
from rest to exercise. Explain how the vasomotor centre controls this distribution.
[4]
2.
4 marks max:
(Describe)
1.
More blood is distributed to the working muscles.
2.
Less blood is distributed to non-essential organs
(Explanation)
3.
3.
Vasodilation of arteries/arterioles supplying working muscles/Vascular shunt
4.
Opening/vasoldilation of precapillary sphincters supplying working muscles
5.
Vasoconstriction of arteries/arterioles supplying non-essential organs
6.
Closing/vasoconstriction of precapillary sphincters supplying non essential organs
Large amounts of blood need to be circulated around the body during prolonged aerobic
exercise.
(i)
Identify the mechanisms of venous return that ensure a sufficient supply of blood is
returned to the heart during exercise.
Give one reason why a good venous return helps a performer.
3.
[4]
(i)
1
Valve
2
Skeletal muscular pump
3
Respiratory pump
© Owned by or under licence to Pearson Publishing Oxford Limited 2008
[4]
1
Unit 3 part II Response of the Cardiovascular (Vascular) system to physical activity
4
Venoconstriction/venomotor control/smooth muscle
5
Gravity for blood from above heart
1 mark max how it helps
4.
1.
Increase stroke volume
2.
Increase cardiac output
3.
Therefore more blood/oxygen supplied to working muscles
4.
Greater amounts of carbon dioxide removed via lungs
The figure below shows a marathon runner during a five mile training run.
[3]
Identify two ways in which oxygen is transported in the blood during the training run.
Identify two mechanisms of venous return which enable the athlete to deliver deoxygenated
blood back to the heart during the training run.
[2]
4.
2 marks max
1
Carried in the plasma
2
Combines with haemoglobin
3
Forms oxyhaemoglobin/HbO2
2 marks max
5.
2
1
Muscle pump/skeletal muscle pump
2
Valves
3
Venoconstriction/venomotor control
4
Respiratory pump
5
Gravity forces blood back from above heart
[4]
During aerobic performance a large amount of carbon dioxide is produced at the muscles.
Identify two ways in which carbon dioxide is carried in the blood during aerobic performance.
mark first two only
2
1.
Dissolves in the plasma
2.
Combines with haemoglobin
© Owned by or under licence to Pearson Publishing Oxford Limited 2008
2
Unit 3 part II Response of the Cardiovascular (Vascular) system to physical activity
3.
Forms carbaminohaemoglobin
4.
Dissolves in water/forms carbonic acid/forms H2CO3
5.
In plasma dissociates to hydrogen ions/bicarbonate ions
6. Outline the changes that occur in the vascular system during a period of submaximal activity
and explain how these changes are controlled.
(10)
Changes submax 5 marks
1.
during exercise the vascular system redistributes blood
2.
so that areas with the greatest need / skin /muscles receive more blood
3.
this mechanism can increase the volume of blood going to the working muscles
fourfold
4.
and areas with low demand / liver receive less blood
5.
this is called the vascular shunt mechanism
6.
opening and closing of the pre-capillary sphincters
7.
Increase in blood pressure
8.
(a fall in blood pressure) causes vasoconstriction / constriction of the
arteries feeding the less important tissues
9.
causes vasodilation / dilation of the arteries feeding tissues with the greatest need for O2
10.
pH/ blood acidity/ blood CO2 / H+ ions /
temperature / changes in blood viscosity
O2 tension /
blood
Control – 1 mark or each up to a sub-max of 5
11.
Vasomotor control
12.
vasomotor centre stimulated by changes in blood pressure
13.
detected by baroreceptors (in the aorta and carotid arteries)
14.
Sympathetic nervous system
15.
controls the muscular layer of a blood vessel
16.
increased sympathetic stimulation (causes vasoconstriction)
17.
decreased sympathetic stimulation (causes vasodilation)
18
Pre-capillary sphincters / ring shaped muscle at the opening of a capillary
19.
controls blood flow into the capillary bed
20.
(contraction/closed) restricts blood flow through the capillary bed
21.
(relaxation/open) increases blood flow through the capillary bed
© Owned by or under licence to Pearson Publishing Oxford Limited 2008
3