2.2 The cardiovascular system

Question 1

What is the function of the cardiovascular system?

Answer 1

Transport:
Oxygen vs Carbon Dioxide, Nutrient delivery from digestive tract, Waste removal, Hormones.

Protection:
Inflammation, WBC destroy microorganisms and cancer cells, Antibodies, Platelets and blood clotting

Regulation:
Body temperature, stabilise pH and fluid distribution.

Question 2

Where is blood produced?

Answer 2

Red bone marrow site of production of erythrocytes & leucocytes

Question 3

State the composition of blood

2.1

Answer 3

4 components:

erythrocytes 45%
plasma 55%
leucocytes & platelets <1%

blood transports electrolytes, proteins, gases, nutrients, waste products, hormones

Question 4

Distinguish between the functions of erythrocytes, leucocytes and platelets.

2.2

Answer 4

Erythrocytes (RBC):
hemoglobin protein binds to oxygen -> oxyhemoglobin.

Leucocytes (WBC):
part of immune system, protects body against infection & foreign invaders. Fight pathogens such as bacteria, viruses, or parasites.

Platelets:
Form blood clots to prevent the loss of blood.

Question 5

Outline the role of hemoglobin in oxygen transport

Answer 5

RBD site of transport:

Oxygen transported in blood as oxyhemoglobin. Hemoglobin has 4 binding sites for individual O molecules to bind to.

Question 6

Describe the anatomy of the heart with reference to the heart chambers, valves and major blood vessels.

2.3

Answer 6

Chambers:
Right & Left: Atrium & Ventricle

Valves:
Pulmonary, aortic, tricuspid, bicuspid

Blood vessels:
Aorta, pulmonary vein, pulmonary artery, vena cava

Question 7

Define pulmonary & systemic circulation

Answer 7

pulmonary circulation- Delivers deoxygenated blood from right side of the heart to the lungs to be oxygenated. Then carried back to left side of heart.

systemic circulation- Delivers oxygenated blood from left side of the heart to the body & capillaries. Then carried back to right side of heart.

Question 8

Outline the relationship between the pulmonary and systemic circulation.
2.5

Answer 8

-

Question 9

What are arteries?

Answer 9

thick muscular walls; O2 rich (except pulmonary artery); transport blood away from the heart

Question 10

What are capillaries?

Answer 10

narrow vessels with thin walls; site of exchange between blood & tissue

Question 11

What are veins?

Answer 11

deoxygenated blood (except pulmonary veins); less muscular; valves to prevent back flow; to heart

Question 12

What are valves?

Answer 12

Veins contain valves to stop the blood from flowing backwards due to gravity. This is because the blood inside is at low pressure.

Question 13

Define:
Cardiac Output (CO) (l/min)
Stroke volume (SV) (l)
Heart Rate (HR) (bpm)

2.6

Answer 13

Cardiac Output (CO) (l/min) - The amount of blood ejected by the heart (ventricles) in 1 minute
-> takes approx 1 min for blood to return & pass through the heart OR. in other wordsAny RBC leaving the left ventricle will be back in approx 1 min

Stroke volume (SV) (l) - The amount of blood being pumped from the heart during each contraction

Heart Rate (HR) (bpm) - How quickly the heart is beating (per minute)

Question 14

Whats the relationship btw. HR & SV? Why?

2.6

Answer 14

CO = HR x SV

People with higher resting SV have lower resting HR.

-> The more blood you can pump per ventricular contraction, the less your heart needs to beat to pump the blood around your body.

Question 15

Analyse cardiac output, stroke volume and heart rate data between gender

2.7

Answer 15

-women have lower stroke volume-> smaller heart & smaller left ventricle
-women have smaller blood volume
-women have higher resting & sub-maximal heart rate -> maintain cardiac output
-max heart rate same

Question 16

Analyse cardiac output, stroke volume and heart rate data between ages

2.7

Answer 16

-children lower stroke volume ->size
-young children have higher resting & working working heart rate -> maintain cardiac output
-w/ age stroke volume increases & heart rate decreases
-older adults have decrease in cardiac output -> bcus of decrease in stroke volume & heart rate
-older adults have much smaller max heart rate

Question 17

Explain cardiovascular drift.

2.8

Answer 17

the progressive increase in heart rate and decrease in stroke volume that begins after approximately 10 min of prolonged moderate-intensity exercise, is associated with decreased maximal oxygen uptake, particularly during heat stress.

Question 18

Describe how cardiovascular drift occurs during a marathon (5)

Answer 18

Question 19

Why does stroke volume decrease, during cardiovascular drift?

Answer 19

Body fluids are lost, reducing the volume of blood returning to the heart causing a decrease in stroke volume

Question 20

Explain the physiological changes which contribute to a person experiencing cardiovascular drift during an endurance event. (4)

2.9

Answer 20

Question 21

Define the terms systolic and diastolic blood pressure.

2.9

Answer 21

Systolic:
max pressure in the artery during ventricular contraction
(force exerted by blood on arterial
walls during ventricular contraction)

Diastolic:
minimum pressure in the artery during ventricular relaxation (force exerted by blood on arterial
walls during ventricular relaxation)

Question 22

Why does systolic blood pressure sometimes decrease during exercise and diastolic doesn’t? (3)

2.10

Answer 22

Question 23

Analyse systolic blood pressure response of an endurance runner (4)

Answer 23

Question 24

Explain how running versus static exercises affect systolic and diastolic blood pressure levels. (4)

Answer 24

Question 25

Analyse systolic and diastolic blood pressure during: -dynamic exercise -static exercise -rest 2.10 & .11

Answer 25

Dynamic exercise- (moderate aerobic exercise) - systolic pressure increase : first few minutes - diastolic pressure remains relatively unchanged Static exercise- (heavy resistance exercise) - increase blood pressure for both Recovery - (after a bout of moderate exercise ) - systolic blood pressure temporarily decreases

Question 26

Analyze the distribution of blood during maximal exercise. [6]

Answer 26

Question 27

Explain the mechanism of blood redistribution during a long-distance cycling race. (5) 2.12

Answer 27

Question 28

Explain the changes in blood distribution that occur during an endurance training run. (3) 2.12

Answer 28

Question 29

Describe the cardiovascular adaptations resulting from endurance exercise training. 2.13

Answer 29

-

Question 30

Explain maximal oxygen consumption. 2.14

Answer 30

maximal O2 consumption = VO₂ max -amount of oxygen a person consumes in a set period of time (usually a minute) ⟶ those who have a higher fitness level have higher VO₂ max values and can exercise more intensely than those who are not as well conditioned

Question 31

How is VO₂ max calculated?

Answer 31

Fick Equation: During Max exercise it summarises the relationship between: Maximum Cardiac Output-(CO) Maximum Arterio-Venous Difference- (a-v)O2 VO2 Max VO2 max = Max CO x Max (a-v)O2

Question 32

What factors affect VO2 max? 2.15

Answer 32

Factors affecting VO2 max: * Heredity * Age * Gender * Body size and composition * Mode of exercise * Types of muscle fibers used during the exercise * Altitude * Temperature * Training status

Question 33

Discuss the variability of maximal oxygen consumption in selected groups. 2.15

Answer 33

Groups: **Age** - decreases with age **Trained vs Untrained** - higher in trained and lower in untrained **Male vs Female** - higher in males than females -> Differences in body composition -> Hemoglobin concentration

Question 34

How does training increase VO2max?

Answer 34

**Increase in stroke volume** -increased in the volume of the left ventricle (sub-maximal & maximal values) **Increased number of capillaries** -so that more blood can supply oxygen to the exercising muscles.

Question 35

What effect does strenuous exercise have on CO2?

Answer 35

Strenuous exercise can increase CO to 21L/min in a fit person and 35L/min in world-class athletes.

Question 36

Why should we train if one's VO2 max is genetic anyway?

Answer 36

We may have a ‘ceiling’ VO2 max that is determined by our genes, but this will only become limiting once a person has trained and increased their VO2max as much as possible to reach this ceiling.

Question 37

Discuss the variability of maximal oxygen consumption with different modes of exercise. 2.16

Answer 37

**Highest values**: treadmill exercise -> more muscles are being used **Lowest values**: bicycle ergometer test arm ergometry ->participant is sitting down and only using their arms, which requires less oxygen going to the muscles

Question 38

What is affected by training more HR or SV?

Answer 38

- Our maximum HR remains the same, however with training one can tolerate a higher HR for longer. - SV is affected the most by training as physical changes to the heart (increase in the left ventricle) result in a higher SV, thus more cardiac output. (CO)

Question 39

Explain Absolute VO2 max vs Relative VO2 max.

Answer 39

**Absolute VO2 Max**: Does NOT account for differences in size and mass Expressed in L/min Relative **Relative VO2 Max**: Does account for differences in size and mass. Expressed in ml/kg/min

Question 40

What is Max (a-v)O2

Answer 40

The (a-v)O2 is an indication of how much oxygen has been removed by the capillaries and used by the body.

Question 41

What is intrinsic regulation of the heart rate? 2.4

Answer 41

The intrinsic regulation of heart rate means that the heart can beat on its own without needing commands from the brain, thanks to special cells that act like a natural pacemaker.

Question 43

What is the extrinsic regulation of the heart rate? 2.4

Answer 43

Extrinsic regulation of heart rate involves external factors, such as signals from the nervous system and hormones, which influence the heart rate in response to changes in the body's needs or conditions, like during exercise or stress.

Question 44

Outline intrinsic regulation of the heart rate. 2.4

Answer 44

Heart stimulates itself to contract --> Pacemaker system 1. SA node (pacemaker) fires a cardiac impulse, starts in wall of right atrium, causing the 2 atria to contract simultaneously (almost) 2. W/ slight delay, cardiac impulse reaches the AV node, giving ventricles time to fill with blood. 2. Impulse then passes down septum of heart which splits left & right around heart -> impulse spread around walls of ventricles so they contract again. 4. Ventricles relax & cycle repeats

Question 45

Describe the pathway of the electrical impulse during excitation of the heart muscle. (4) 2.4

Answer 45

Question 46

What is the role of extrinsic regulation of the heart rate?

Answer 46

1. **Chemoreceptors** * Detect changes in blood pH, carbon dioxide and oxygen. * In the aortic arch, carotid arteries send information to the cardiac centre in the brain stem. 2. **Baroreceptors** * Blood Pressure Receptors * When HR drops, send impulses to the cardiac centre --> sends signal back to heart, increasing firing rate of the SA node bringing the HR, CO and Blood Pressure back to normal. * When HR spikes, so to does blood pressure at the Baroreceptors. 3. **Proprioceptors** * sensors that provide information about joint angle, muscle length, and muscle tension. * Detect changes in physical activity & allow heart to change output before muscles require extra oxygen. 4. **Emotions & Drugs**. * (Example) caffeine will stimulate the Sympathetic & speeding up the SA node thus releasing adrenaline. K+ potassium and calcium deficiency causes the parasympathetic nervous system to release acetlycholine which decreases HR.

Question 47

State the receptor in the aorta which responds to carbon dioxide and pH levels in the blood (1)

Answer 47

Question 48

What is blood pressure?

Answer 48

measurement of the force of blood against the artery walls as the heart pumps it throughout the body

Question 49

How is a blood pressure reading expressed? (which numbers?)

Answer 49

Systolic blood pressure Dystolic blood pressure