Cardiovascular system (quiz)

Question 1

Give an average value for cardiac output for a performer at rest and during maximal exercise. (2)

Answer 1

At Rest: 4—6l/min
During Exercise: 20—40 l/min

Question 2

Describe how the conduction system of the heart controls the systolic phase of the cardiac cycle. (5)

Answer 2

SANinitiatesan impulse, this causesatrialsystole blood forced from the atria to the ventricles through AV valves
Impulse is received by the AV node
Impulse continues down the bundle of Hisandto the Purkinje fibres
Causingventricularsystole blood is ejected from the ventricles via the semi-luna valves

Question 3

Explain the cardiac cycle of the heart (3)

Answer 3

Atrial systole is when the atria contractwhichforces blood into the ventricles
Ventricular systole is when the ventricles contractwhichpumps blood out of the heart to the body and the lungs
Diastole is when the atria and ventricles relaxwhichallows blood to enter heart.

Question 4

Describe neural factors which regulate the cardiac system (6)

Answer 4

Neural control is under Autonomic Nervous System uses the sympathetic nervous system to increase heart rate
Receptors detect change
Cardiac System information sent to the cardiac control centre (in medulla oblongata)
Impulses sent via the cardiac accelerator nerve to stimulate the SA node
Overall effect…increases cardiac output or Q as SVxHR=Q

Question 5

What is the role of the chemoreceptor

Answer 5

detectincreasein (pp)CO2 or acidity
detectdecreasein (pp)O2 or pH

Question 6

What is the role of the proprioceptors

Answer 6

detect (increase in) motor activity or movement

Question 7

What is the role of the baroreceptor

Answer 7

detectincreasein blood pressure
detectincreasedstretch of arterial wall
detectincreasedstretch of lung walls

Question 8

What is the role of the chemoreceptor

Answer 8

detectincreasein blood temperature

Question 9

Define the term ‘stroke volume’ and give a typical resting value for a trained individual. (2)

Answer 9

Amount of blood pumped out of the left ventricleper beat
80 – 120ml

Question 10

Give an average value for cardiac output for a performer at rest and during maximal exercise (2)

Answer 10

During rest: 4—6l/min
During maximal exercise: 20—40 l/min

Question 11

Describe how the conduction system of the heart controls the systolic phase of the cardiac cycle. (4)

Answer 11

SA node or sino-atrial node or SAN initiates or sends an impulse, this causesatrialsystole
Blood forced or pushed or flows from the atria to the ventricles or out of the atria or through AV valves
Impulse travels to or is received by the AV node or atrio-ventricular node or AVN / AV node sends impulse
Impulse continues down the bundle of Hisandto the Purkinje fibres causingventricularsystole
Blood is ejected from the ventricles

Question 12

Explain how the conduction system of the heart controls diastole. (1)

Answer 12

Atria relax Atria/ventricles do not contract
No impulse due to …No impulse

Question 13

Heart Rate Definition (1)

Answer 13

Heart rate is the number of ventricular contractions in a minute

Question 14

Stroke Volume Definition (1)

Answer 14

Stroke volume is the volume of blood ejected from left ventricle per beat

Question 15

Cardiac Output Definition (1)

Answer 15

Cardiac output is the volume of blood ejected from the left ventricle per minute
Q=HR × SV

Question 16

Vascular shunt Mechanism (1)

Answer 16

Vascular shunt is the redistribution of blood flow during exercise

Question 17

Venous Return Definition (1)

Answer 17

The return of blood to the right atrium from the vena cava

Question 18

Venous Return Increase (1)

Answer 18

VR increases in exercise due to increased impact of muscle pump

Question 19

Explain the changes to stroke volume during sub maximal exercise. (1)

Answer 19

Stroke volume is dependent on venous return
During some maximal exercise increased venous return = increased stroke volume
Reduced filling time of heart
Smaller end diastolic volume
Which means heart is only partially filled with blood

Question 20

Describe intrinsic control of the heart during exercise. (4)

Answer 20

Increasein venous return
Therightatrium stretches
Which causes the SA node toincreaserate of firing.
Increasing end diastolic volume
Moreblood enters theleftventricle which will cause it to stretch
This in turnincreasesthe stroke volume
Temperatureincreaseswhichincreasesheart rate
Increased Temperatureincreasesthe speed of nerve impulses

Question 21

Explain how cardiovascular adaptations as a result of an aerobic training programme can enhance aerobic capacity (6)

Answer 21

Myocardial hypertrophy
Stronger contractions
Increased stroke volume
Increased maximal cardiac output.
Increased capillarisation at both muscles, tissues and lungs
Greater surface area leading to greater gaseous exchange
Increased buffering capacity
Improved vascular shunt mechanism
Increased elasticity of arterial walls.
Increased blood (plasma) volume
Decreased viscosity of blood
Increased red blood cells
Increase oxygen to muscles
Speed up lactic acid removal
Lower blood pressure

Question 22

Explain the cardiac cycle of the heart using the following key terms, Atrial systole, ventricular systole, diastole (3)

Answer 22

Atrial systole, atria contractwhichforces blood into the ventricles
Ventricular systole, ventricles contractwhichpumps blood out of the heart
Diastole, relaxationwhichallows blood to enter heart

Question 23

Identify the threeneural receptors and explain how each regulates heart rate as the dance routine begins. (3)

Answer 23

Chemoreceptors - detectincreasein blood acidity
Proprioceptors - detect movement
Baroreceptors - detectincreasein blood pressure

Question 24

Explain how neural factors control heart rate at the start of exercise

Answer 24

Heart rate regulated by the autonomic nervous system
Cardiac control centre receives information from the receptors
Chemoreceptors detectincreased acidity in the blood
Proprioceptors detect movement
Baroreceptors detectincreasedblood pressure
Sympathetic nervous system to increase heart rate
SA node increases heart rate

Question 25

Explain how neural factors control heart rate during recovery.

Answer 25

Chemoreceptors detect decreased in acidity Proprioceptors / mechanoreceptors detectmovement Baroreceptors detect decreased blood pressure Parasympathetic nervous system to decrease heart rate SA node decreases heart rate

Question 26

Explain how venous return mechanisms can aid venous return and prevent blood pooling as part of the netball player’s recovery (4)

Answer 26

Venous return mechanisms work to increase blood flow back to heart Which means netballer will speed up removal of lactic acid Pocket valves in veins prevent backflow of blood Skeletal muscle pump causes muscles of legs to contract squeezing veins Smooth muscle in walls of veins contracts Respiratory pump causes pressure differences within thoracic cavity

Question 27

Explain how the changes in the distribution of blood to the skeletal muscles and other organs is achieved during exercise (4)

Answer 27

Increase in heart rate/stroke volume/cardiac output means greater volumes of blood to muscles Vasodilation of blood vessels leading to muscles Dilation of pre-capillary sphincters to muscles Vasoconstriction of blood vessels leading to other organs Constriction of pre-capillary sphincters to other organs

Question 28

Explain how the muscle and respiratory pumps cause changes to venous return during exercise and during recovery. (2)

Answer 28

Exercise - More forceful muscular contractions cause VR to increase Recovery - Less forceful muscular contractions cause VR to decrease

Question 29

Outline why completing a cool down after exercise aids venous return (2)

Answer 29

The action of the muscle pump is maintained above resting level and gradually decreases Blood pooling avoided as blood continues to move towards the heart The action of the respiratory pump is maintained above resting level and gradually decreases because ventilation rate remains higher than at rest

Question 30

Identify mechanisms of venous return. (5)

Answer 30

Skeletal or muscle or muscular pump Pocket valves Respiratory muscle pump Smooth muscle Gravity

Question 31

Explain how an increase in venous return during exercise affects the quality of an athlete’s performance. (5)

Answer 31

… causes the walls of the atria to stretch which stimulates the SA node to increase heart rate or firing rate or rate of impulses … causes the walls of the ventricles to stretch which causes a stronger force of contraction Increase in stroke volume and therefore cardiac output increase blood or oxygen supply to muscles increases endurance and delays fatigue

Question 32

Two mechanisms that aid venous return are the muscle pump and the respiratory pump. Describe these two venous return mechanisms. (2)

Answer 32

Muscle pump: Skeletal) muscles contract which compresses the veins Respiratory pump: Breathing causes a pressure difference between the thoracic cavity and abdominal cavity

Question 33

Explain how the muscle and respiratory pumps cause changes to venous return during exercise and during recovery. (2)

Answer 33

More forceful muscular contractions cause VR to increase Less forceful muscular contractions cause VR to decrease

Question 34

Outline why completing a cool down after exercise aids venous return (1)

Answer 34

The action of the muscle pump is maintained above resting level and gradually decreases Blood pooling reduced because blood continues to move towards the heart The action of the respiratory pump is maintained above resting level and gradually decreases

Question 35

What term is used to describe the re-distribution of blood during physical activity (1)

Answer 35

Vascular shunt

Question 36

Explain how this re-distribution of blood during physical activity is achieved. (4)

Answer 36

More blood goes to the working muscles and less blood to non-essential organs Role of the vasomotor centre in passing on messages about where blood is needed Vasodilation of arterioles leading to muscles Vasoconstriction of arterioles leading to some organs Opening of pre-capillary sphincters to muscles Closing of pre-capillary sphincters to organs

Question 37

Explain how this re-distribution of blood during physical activity is achieved. (4)

Answer 37

More blood goes to the working muscles and less blood to non-essential organs Role of the vasomotor centre in passing on messages about where blood is needed via chemoreceptors / proprioceptors / baroreceptors Vasodilation of arterioles leading to muscles Vasoconstriction of arterioles leading to some organs Opening of pre-capillary sphincters to muscles Closing of pre-capillary sphincters to organs