Cardiovascular system

• What is one major impact of physical activity on the heart?


  It helps to strengthen the heart muscle and increases the size of the left ventricle.
• How does physical activity affect the incidence of heart disease?


  It reduces the potential incidence of heart disease.
• What health risk is associated with high blood pressure?

  There is a higher force exerted against the blood vessel wall.
• How does physical activity influence cholesterol levels?


  It reduces the adverse effects of high cholesterol levels.
• What is one potential benefit of physical activity regarding strokes?

  It reduces the likelihood/incidence of a stroke.
• What is cardiac output and how is it calculated?

  Cardiac output (Q) is calculated as stroke volume (SV) x heart rate (HR).
• What happens to cardiac output during exercise?

  Cardiac output increases due to an increase in stroke volume and heart rate.
• What are the stroke volume and heart rate values for an untrained person during exercise?

  • Stroke volume: 120 ml
  • Heart rate: 202 bpm
  • Cardiac output: 24.24 litres
• What are the stroke volume and heart rate values for a trained person during exercise?

  • Stroke volume: 170 ml
  • Heart rate: 202 bpm
  • Cardiac output: 34.34 litres
• What are the stroke volume and heart rate values for an untrained person at rest?

  • Stroke volume: 70 ml
  • Heart rate: 72 bpm
  • Cardiac output: 5.04 litres
• What are the stroke volume and heart rate values for a trained person at rest?

  • Stroke volume: 84 ml
  • Heart rate: 60 bpm
  • Cardiac output: 5.04 litres
• What is cardiovascular drift?

  It is the increase in heart rate during prolonged endurance exercise despite the intensity remaining the same.
• What causes cardiovascular drift?

  It is often caused by fluid loss (sweat) and increased core body temperature.
• Why is it important to maintain high fluid consumption before and during exercise?

  To prevent cardiovascular drift caused by fluid loss and increased core body temperature.
• What are the hormonal, neural, and chemical regulation responses during physical activity?

  • Anticipatory rise: Increase in heart rate before activity due to adrenaline.
  • Redistribution of blood: Vascular shunt mechanism (vasoconstriction and vasodilation).
  • Cardiac conduction: Electrical impulse causing heart contraction.
  • Carbon dioxide: Exhaled during breathing.
  • Sympathetic system: Speeds up heart rate.
  • Parasympathetic system: Decreases heart rate.
• What are the main receptors involved in the regulation of responses during physical activity?

  • Chemoreceptors: Detect changes in blood acidity.
  • Proprioceptors: Detect changes in muscle movement.
  • Baroreceptors: Respond to changes in blood pressure.
• What is the primary function of blood?

  The transportation of oxygen.
• What is haemoglobin?


  An iron-containing pigment found in red blood cells that combines with oxygen.
• What is oxyhaemoglobin?

  Haemoglobin combined with oxygen.
• What does the oxyhaemoglobin dissociation curve represent?


  It represents the relationship between oxygen and haemoglobin and how haemoglobin transports and releases oxygen.
• What does a shift to the right of the oxyhaemoglobin dissociation curve indicate?

  It indicates that muscles require more oxygen, leading to easier dissociation of oxygen from haemoglobin.
• What is venous return?


  • The return of blood to the right side of the heart via the vena cava.
  • Active mechanisms include the skeletal muscle pump, respiratory pump, and pocket valves.
• What is the relationship between stroke volume and blood pumped into the heart?


  The more blood that is pumped into the heart, the more blood must be pumped out, resulting in an increase in stroke volume.
• What is the arteriovenous oxygen difference (A-VO2 difference)?


  It is the difference between the oxygen content of arterial blood arriving at the muscles and venous blood leaving the muscles.
• How does the body adapt to exercise over time?

  The body becomes more efficient over time, resulting in a positive training effect.
• What is the Bohr shift?

  It is the additional oxygen released from haemoglobin at lower pH and higher carbon dioxide concentration in the tissues.
• What happens to haemoglobin in tissues with low partial pressure of oxygen and high partial pressure of carbon dioxide?

  Haemoglobin unloads oxygen more readily in these conditions.
• How does blood redistribution differ at rest compared to during exercise?

  • At rest: Blood is distributed evenly.
  • During exercise: More blood is directed to skeletal muscles to meet increased oxygen demand.