Topic 1 Chapter 4: 1.2.5 - 1.2.9 - The Cardiovascular System Flashcards
(129 cards)
1
Q
What is the main function of the heart?
A
To pump blood throughout the body, supplying oxygen and nutrients and removing waste products.
2
Q
How many chambers does the heart have?
A
Four chambers – two atria (upper) and two ventricles (lower).
3
Q
What separates the left and right sides of the heart and why is it important?
A
The septum – a muscular wall that prevents mixing of oxygenated and deoxygenated blood
4
Q
What is the role of the right atrium?
A
It receives deoxygenated blood from the body via the superior and inferior vena cava.
5
Q
What is the function of the right ventricle?
A
It pumps deoxygenated blood to the lungs through the pulmonary artery.
6
Q
What is the function of the left atrium?
A
It receives oxygenated blood from the lungs via the pulmonary veins.
7
Q
What is the function of the left ventricle?
A
It pumps oxygenated blood to the body through the aorta. It has the thickest walls due to the high pressure needed.
8
Q
What are the four main valves of the heart?
A
Tricuspid, pulmonary, bicuspid (mitral), and aortic valves.
9
Q
What is the function of heart valves?
A
To prevent backflow of blood and ensure it flows in one direction.
10
Q
Where is the bicuspid (mitral) valve located?
A
Between the left atrium and the left ventricle.
11
Q
Where is the tricuspid valve located?
A
Between the right atrium and the right ventricle.
12
Q
What is the role of the pulmonary valve?
A
It prevents backflow of blood from the pulmonary artery into the right ventricle.
13
Q
What is the role of the aortic valve?
A
It prevents backflow of blood from the aorta into the left ventricle.
14
Q
Why is the left ventricle wall thicker than the right?
A
Because it needs to pump blood at high pressure throughout the entire body.
15
Q
What are coronary arteries?
A
Blood vessels that supply oxygen-rich blood to the heart muscle itself.
16
Q
What is the role of the sinoatrial (SA) node?
A
The SA node is the heart’s natural pacemaker. It generates electrical impulses that initiate each heartbeat.
17
Q
Where is the SA node located?
A
In the wall of the right atrium.
18
Q
What happens after the SA node fires?
A
The electrical impulse spreads through the atria, causing atrial contraction (atrial systole).
19
Q
What is the function of the atrioventricular (AV) node?
A
It delays the impulse to allow the atria to fully contract and empty blood into the ventricles before ventricular contraction.
20
Q
Where is the AV node located?
A
Between the atria and ventricles, near the interatrial septum.
21
Q
What structures transmit the impulse from the AV node to the ventricles?
A
The Bundle of His, right and left bundle branches, and Purkinje fibres.
22
Q
What do the Purkinje fibres do?
A
They rapidly conduct the impulse throughout the ventricular walls, causing ventricular contraction (ventricular systole).
23
Q
What is the order of the cardiac conduction pathway?
A
SA node → atria → AV node → Bundle of His → bundle branches → Purkinje fibres → ventricles.
24
Q
Which part of the nervous system can influence the cardiac conduction system?
A
Both the sympathetic (increases rate) and parasympathetic (decreases rate) nervous systems.
25
What is the cardiac cycle?
The complete sequence of events in one heartbeat, including contraction (systole) and relaxation (diastole) of the heart chambers.
26
What are the three phases of the cardiac cycle?
Atrial systole, ventricular systole, and diastole.
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What happens during atrial systole?
The atria contract, pushing blood into the ventricles.
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What happens during ventricular systole?
The ventricles contract, pushing blood into the aorta and pulmonary artery.
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What happens during diastole?
The heart muscles relax, the chambers fill with blood, and the coronary arteries receive blood.
30
What valves are open during atrial systole?
The atrioventricular (AV) valves (tricuspid and bicuspid/mitral).
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What valves are open during ventricular systole?
The semilunar valves (pulmonary and aortic).
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What causes the ‘bah-dah’ sound of the heartbeat?
‘Bah’ = AV valves closing during ventricular systole
‘Dah’ = semilunar valves closing during diastole.
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How long does the cardiac cycle typically last at rest?
About 0.8 seconds.
34
What is Heart Rate?
The number of times the heart beats per minute (bpm).
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What is Maximal Heart Rate (HRmax) and give the equation?
The highest number of heartbeats per minute a person can achieve during maximum effort exercise.
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What is the equation for Maximal Heart Rate (HRmax)?
Equation 220 − age (in years)
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What is Heart Rate Reserve (HRR)?
The difference between maximal heart rate and resting heart rate.
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What is the equation for Hear Rate Reserve?
HRR = HRmax − resting heart rate
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What is Stroke Volume (SV)?
The amount of blood pumped out of the left ventricle per beat, measured in millilitres (ml).
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What is Cardiac Output (Q)?
The volume of blood the heart pumps per minute.
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What is the equation for Cardiac Output (Q)?
Equation: Cardiac Output = Heart Rate × Stroke Volume
(Q = HR × SV)
42
What are three short-term cardiac responses to exercise?
- Increases in heart rate
- Stroke volume
- Cardiac output due to greater blood demand and muscle activation.
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What are typical resting and max heart rates for trained vs. untrained individuals?
Trained: Resting HR ~60 bpm, Max ~200 bpm
Untrained: Resting HR ~80 bpm, Max ~190 bpm.
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How do stroke volume and cardiac output differ between trained and untrained people?
Trained individuals have higher stroke volumes and cardiac outputs both at rest and during exercise.
45
What causes the anticipatory rise in heart rate before exercise?
The release of adrenaline and noradrenaline due to excitement or arousal before exercise.
46
Why does heart rate rise sharply at the start of anaerobic exercise?
Due to proprioceptor stimulation, continued hormonal release, and skeletal muscle pump activation.
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What happens to heart rate during aerobic steady-state exercise?
It levels off while the body begins to recover oxygen debt.
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Why does heart rate stay high during maximal workloads?
Continued anaerobic stress produces lactic acid and CO₂, stimulating chemoreceptors and other limiting factors.
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What causes the rapid decrease in heart rate immediately after exercise?
Withdrawal of hormonal and proprioceptive stimuli, and cessation of skeletal muscle pump activity.
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Why is there a slower phase of heart rate recovery after exercise?
Due to the clearance of lactic acid and return of body systems to resting values.
51
What causes the anticipatory rise in stroke volume before exercise?
Hormonal action of adrenaline and noradrenaline increases stroke volume from 60 to 85 ml/beat.
52
Why does stroke volume increase during the onset of exercise?
Due to increased venous return and stronger ventricular contraction (Starling’s Law of the Heart).
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How high can stroke volume rise during submaximal exercise?
Over 110 ml/beat.
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What happens to stroke volume during maximal exercise?
It levels off; heart rate continues to rise to meet oxygen demand.
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How does cardiac output (Q) change with exercise intensity?
It increases linearly with exercise intensity (Q = SV × HR).
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What is cardiovascular drift?
A gradual increase in heart rate and decrease in stroke volume during prolonged aerobic exercise at constant intensity.
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What causes cardiovascular drift?
Fluid loss through sweat leads to reduced plasma volume, venous return, and stroke volume, while heart rate increases to maintain cardiac output.
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How is heat dissipated during cardiovascular drift?
Through vasodilation, which allows heat to move from the core to the skin and escape the body.
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How can cardiovascular drift be minimized?
By rehydrating with fluids containing salt and glucose (electrolytes) during prolonged exercise in hot environments.
60
Where is the cardiac control centre located and what does it do?
In the medulla oblongata; it integrates neural, hormonal, and intrinsic feedback to regulate heart rate.
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What do chemoreceptors detect and how do they affect heart rate?
They detect low O₂, low pH, high CO₂ and H⁺ levels
They stimulate heart rate increase via the cardiac accelerator nerve.
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What do proprioceptors detect and how do they influence heart rate?
They detect movement and tension in muscles/tendons
They increase heart rate via the cardiac accelerator nerve.
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What do baroreceptors do when blood pressure is high?
They trigger the parasympathetic nervous system to release acetylcholine
They slow the heart rate.
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What is the effect of adrenaline and noradrenaline on the heart?
They increase heart rate (tachycardia) and stroke volume via stronger ventricular contraction.
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What hormone slows heart rate and how?
Acetylcholine, released by the parasympathetic nervous system, induces bradycardia.
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How do thyroid hormone and glucagon affect heart rate?
They increase heart rate; glucagon also promotes glycogen breakdown for muscle energy.
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What is venous return and why is it important?
The volume of blood returning to the heart; it directly affects stroke volume via Starling’s Law.
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What factors influence venous return?
Skeletal and respiratory pumps, electrolyte balance (Na⁺, K⁺), and myocardial temperature.
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What does Starling’s Law of the Heart state?
Cardiac output equals venous return; increased return stretches ventricles, boosting stroke volume.
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How does the sympathetic nervous system affect heart rate?
It releases adrenaline and noradrenaline via the cardiac accelerator nerve to speed up heart rate.
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How does the parasympathetic nervous system regulate heart rate?
It releases acetylcholine via the vagus nerve to slow down heart rate.
72
What structural change happens to the heart with regular aerobic training?
Cardiac hypertrophy – the heart muscle becomes larger and stronger.
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What is the effect of cardiac hypertrophy on stroke volume?
It increases stroke volume because the heart pumps more blood per beat.
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What is bradycardia and why does it occur in trained athletes?
A resting heart rate below 60 bpm due to a more efficient and stronger heart.
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How does cardiac output change at rest after training?
It remains the same because stroke volume increases while heart rate decreases.
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How does cardiac output change during maximal exercise after training?
It increases significantly due to increased stroke volume and heart rate.
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Why do trained athletes have faster heart rate recovery after exercise?
Because of more efficient cardiac function and parasympathetic dominance.
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How does aerobic training affect the balance between PNS and SNS?
It leads to parasympathetic dominance, contributing to bradycardia.
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What is used as an index of cardiovascular fitness?
Heart rate recovery.
80
How does training affect the SA node?
It decreases the intrinsic firing rate, slowing the resting heart rate.
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What is the function of the systemic circulatory system?
It delivers oxygenated blood to the body and returns deoxygenated blood to the heart.
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What is the function of the pulmonary circulatory system?
It transports deoxygenated blood to the lungs and returns oxygenated blood to the heart.
83
What are the three layers of most blood vessels?
Tunica intima, tunica media (smooth muscle), and tunica externa.
84
What structural changes in blood vessels improve oxygen delivery?
Increased capillarisation in alveoli and muscles, increased RBCs, and myoglobin content.
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What effect do these changes have on performance?
Increased oxygen delivery and reduced fatigue = improved endurance performance.
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What is End Diastolic Volume (EDV)?
The volume of blood in the ventricles at the end of diastole (filling phase).
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What is End Systolic Volume (ESV)?
The volume of blood in the ventricles after contraction (systole).
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How does hypertrophy affect stroke volume?
Increases it by enhancing ventricular filling and force of contraction.
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Why does the heart beat more efficiently after adaptation?
It pumps more blood per beat, reducing the need for a high heart rate.
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What is the formula for cardiac output?
Cardiac Output (Q) = Heart Rate × Stroke Volume
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What is the average cardiac output at rest?
5 litres per minute.
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What happens to cardiac output during exercise?
It increases significantly to meet oxygen demands.
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What is the vascular shunt mechanism?
The redistribution of blood flow to working muscles during exercise.
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What % of blood goes to muscles at rest vs. during exercise?
At rest: 15–20% to muscles, 80–85% to organs
During exercise: 80–85% to muscles, 15–20% to organs
94
What does the VCC control?
The vascular shunt mechanism – redistribution of blood flow.
95
What role do chemoreceptors play in vasomotor control?
Detect increased CO₂, decreased O₂, and pH → stimulate increased sympathetic output.
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What do baroreceptors detect?
Changes in blood pressure.
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How does the VCC respond to this sensory input?
- Increases sympathetic stimulation
- Vasoconstricts arterioles and pre-capillary sphincters of organs
- Vasodilates vessels supplying working muscles
98
What happens to body temperature during a warm-up?
It increases, which decreases blood viscosity and improves blood flow.
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How does a warm-up affect heart rate (HR) and cardiac output (Q)?
Both increase, leading to greater blood flow and oxygen delivery to muscles.
100
What happens to minute ventilation during a warm-up?
It increases, allowing more oxygen into the lungs for gaseous exchange.
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What is vascular shunting and how does it occur during a warm-up?
Redistribution of blood to working muscles via vasodilation and vasoconstriction.
102
How does blood pressure respond to a warm-up?
It slightly increases.
103
What hormone is released during a warm-up and what is its effect?
Adrenaline is released, increasing metabolic rate and energy production.
104
What is the effect of increased temperature on oxygen dissociation?
It speeds up the release of O₂ from haemoglobin to myoglobin, increasing O₂ supply to muscles.
105
Overall, what does a warm-up prepare the body for?
It prepares physiological systems to meet the demands of exercise intensity, oxygen, and energy requirements.
106
What is obesity?
An excess of adipose tissue caused by energy intake exceeding energy expenditure.
107
What are common causes of obesity?
Inactive lifestyle, poor diet, lack of exercise, and high fat consumption.
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What is the Body Mass Index (BMI) threshold for obesity?
A BMI greater than 30.
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What is a limitation of BMI?
It doesn't account for muscle mass.
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What are the body fat % thresholds for obesity?
- Men: >25%
- Women: >35%
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What is energy balance?
The relationship between energy intake and energy expenditure.
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What is positive energy balance?
Energy intake > energy expenditure → leads to fat storage and weight gain.
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What is negative energy balance?
Energy intake < energy expenditure → leads to weight loss.
114
What is coronary heart disease (CHD)?
A condition where fatty deposits build up in the coronary arteries, restricting blood flow to the heart.
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What symptoms might someone with CHD experience?
Chest pain (angina), especially during exertion, due to ischemia (lack of oxygen to heart muscle).
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How does regular aerobic exercise help CHD?
It improves coronary circulation and cardiac function (e.g., lowers resting HR).
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What are three other diseases are associated with obesity?
- Type 2 diabetes
- High blood pressure
- High cholesterol
- Certain cancers (e.g., breast cancer)
- Gallstones
- Metabolic syndrome
118
What happens when glycogen stores are full but energy intake continues?
Excess carbs and fats are stored as triglycerides (fat) in adipose tissue.
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Where is adipose tissue typically stored?
Around major organs, under the skin, and in skeletal muscles.
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Which type of obesity poses the highest health risk?
Upper body (abdominal) obesity.
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How can obesity be controlled?
By achieving a negative energy balance (expending more energy than consumed).
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What is the essential minimum body fat for good health?
- Men: 2–3%
- Women: 8–12%
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What are potential dangers of aiming for low body fat, especially in athletes?
Risk of eating disorders like anorexia nervosa due to severe caloric restriction.
124
What is diabetes?
A condition where the body cannot regulate blood glucose levels due to issues with insulin production or function.
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What hormone regulates glucose and where is it produced?
Insulin, produced by the Isles of Langerhans in the pancreas.
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What is Type 1 diabetes?
Typically occurs in young people; caused by the body failing to produce insulin. Requires daily insulin injections.
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