SEHS Topic 2.2 - Structure and function of the cardiovascular system

2.2.1 - State the composition of blood

Blood is composed of cells (erythrocytes, leukocytes and platelets) and plasma. Blood is also the transport vehicle for electrolytes, proteins, gases, nutrients, waste products and hormones.

2.2.2 - Distinguish between the functions of erythrocytes, leucocytes and platelets

Erythrocytes: Carry oxygen
Leucocytes: Fight infections
Platelets: Aid in blood clotting

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

Four chambers (atria and ventricles), valves (tricuspid, mitral, pulmonary, aortic), and major vessels (aorta, pulmonary arteries, veins)

2.2.4 - Describe the intrinsic and extrinsic regulation of heart rate and the sequence of excitation of the heart muscle

The heart has its pacemaker, but heart rate is also influenced by the sympathetic and parasympathetic branches of the ANS and by adrenaline. (adrenaline has wider metabolic actions, ie increasing glycogen and lipid breakdown.) The electrical impulse is generated at the sinoatrial node (SA node) and travels across the atria to the atrioventricular node (AV node) to the ventricles

2.2.5 - Outline the relationship between the pulmonary and systemic circulation

Pulmonary circulation carries deoxygenated blood to the lungs for oxygenation
Systemic circulation delivers oxygenated blood to the body tissues for cellular respiration

2.2.6 - Describe the relationship between heart rate, cardiac output and stroke volume at rest and during exercise.

Cardiac output = stroke volume × heart rate. Stroke volume expands and heart rate increases during exercise.

2.2.7 - Analyse cardiac output, stroke volume and heart rate data for different populations at rest and during exercise. Limit to males, females, trained, untrained, young and old

Males: HIGHER cardiac output, SV, HR

Trained individuals - HIGHER cardiac output, SV, LOWER HR at rest and during exercise

Young - HIGHER cardiac output, SV, HR

2.2.8 - Explain cardiovascular drift

Gradual increase in heart rate that occurs during prolonged aerobic exercise while maintaining a constant workload. This is influenced by factors such as dehydration, increased body temperature, and decreased stroke volume. As the body works harder to maintain the same level of effort, the heart rate gradually drifts upward. This can lead to decreased performance and increased perceived effort during endurance activities. It's important for athletes to stay properly hydrated, monitor their heart rate, and adjust their pacing strategies to optimize performance and prevent overexertion.

2.2.9 - Define the terms systolic and diastolic blood pressure

Systolic: the force exerted by blood on arterial walls during ventricular contraction
Diastolic: the force exerted by blood on arterial walls during ventricular relaxation

2.2.10 - Analyse systolic and diastolic blood pressure data at rest and during exercise

Data question but -

During cardiovascular exercise, for example, systolic pressure can increase to values close to and over 200 with higher levels of effort. Diastolic pressure, on the other hand, is a relatively stable value during exercise and under daily activity.

2.2.11 - Discuss how systolic and diastolic blood pressure respond to dynamic and static exercise

Dynamic Exercise:

Systolic BP: Increases due to increased cardiac output.

Diastolic BP: Remains stable or may decrease slightly

Static Exercise:

Systolic BP: Increases significantly due to increased vascular resistance

Diastolic BP: Increases markedly due to sustained muscle contraction

2.2.12 - Compare the distribution of blood at rest and the redistribution of blood during exercise

• Rest, blood is evenly distributed throughout the body, with more in systemic circulation.

• During exercise, blood is redistributed to working muscles and skin to meet increased demand.

2.2.13 - Describe the cardiovascular adaptations resulting from endurance exercise training

Increased left ventricular volume resulting in an increased stroke volume and a lower resting and exercising heart rate. Increased capillarisation and increased arterio-venous oxygen difference

2.2.14 - Explain maximal oxygen consumption.

Maximal oxygen consumption (VO2max) represents the functional capacity of the oxygen transport system and is sometimes referred to as maximal aerobic power or aerobic capacity.

2.2.15 - Discuss the variability of maximal oxygen consumption in selected groups.

Training level, gender, age, athleticism

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

• Maximal oxygen consumption varies with different modes of exercise.

• Activities like running typically have higher VO2 max compared to cycling.

• Factors like muscle mass involvement and intensity influence the variability.