Cardiovascular and respiratory system

• What does the cardiovascular system consist of?


  The heart, blood, and blood vessels
• What are the two circuits of the cardiovascular system?

  The pulmonary circuit and the systemic circuit
• What is the function of the pulmonary circuit?


  Circulation of blood through the pulmonary arteries to the lungs and back to the heart
• What is the function of the systemic circuit?


  Circulation of blood through the aorta to the body and vena cava back to the heart
• Why does the left side of the heart have a thicker muscular wall than the right side?


  To forcefully contract and circulate oxygenated blood through the systemic system
• What are the names of the atrioventricular valves?


  The tricuspid and bicuspid valves
• What is the role of the semilunar valves?


  To prevent the backflow of blood from the arteries into the ventricles
• What is the pathway of deoxygenated blood through the heart?

  1. Vena cava
  2. Right atrium
  3. Tricuspid valve
  4. Right ventricle
  5. Semilunar valve
  6. Pulmonary artery
• What is the pathway of oxygenated blood through the heart?

  1. Pulmonary vein
  2. Left atrium
  3. Bicuspid valve
  4. Left ventricle
  5. Semilunar valve
  6. Aorta
• What is oxygenated blood?


  Blood saturated with oxygen and nutrients, such as glucose
• What initiates the contraction of the heart?

  The sinoatrial (SA) node
• What is the role of the AV node in the conduction system of the heart?


  To delay the impulse by 0.1 seconds to allow the atria to finish contracting
• What does the Bundle of His do?


  It splits the impulse in two, ready to be distributed to the ventricles
• What are Purkinje fibres responsible for?


  Distributing the impulse through the ventricle walls, causing them to contract
• What are the phases of the cardiac cycle?


  1. Diastole (relaxation)

  • Atria and ventricles relax
  • Blood flows into ventricles
  • AV valves open, semilunar valves closed

  1. Systole (contraction)

  • Atria contract, forcing blood into ventricles
  • Ventricles contract, AV valves close, semilunar valves open
• What is the typical resting heart rate (HR)?


  72 bpm
• What is stroke volume (SV)?


  The amount of blood ejected from the left ventricle per beat
• What is the typical resting stroke volume (SV)?


  70 ml
• What is cardiac output (CO)?


  The amount of blood ejected from the left ventricle per minute
• How is cardiac output calculated?


  CO = HR × SV
• What is the typical resting cardiac output (CO)?


  5 l/min
• What is bradycardia?


  A resting heart rate below 60 bpm
• How is maximum heart rate calculated?


  220 - age = HRmax (bpm)
• How do heart rate (HR), stroke volume (SV), and cardiac output (CO) compare between untrained and trained individuals at rest?


  • Untrained:
  • HR: 70-72 bpm
  • SV: 70 ml
  • CO: 5 l/min
  • Trained:
  • HR: 50 bpm
  • SV: 100 ml
  • CO: 5 l/min
• What happens to heart rate during exercise?


  HR increases in proportion to the intensity of exercise until maximum is reached
• How does stroke volume respond to exercise intensity?


  SV increases until a plateau is reached at approximately 40–60 percent of working capacity
• What causes stroke volume to increase during exercise?


  Increased venous return and the Frank-Starling mechanism
• Why does stroke volume reach a plateau during sub-maximal intensity exercise?


  Increased HR towards maximal intensities limits time for ventricles to fill completely
• What is the Frank-Starling mechanism?


  Increased venous return leads to increased stroke volume due to increased stretch of the ventricular walls
• What is the difference between sub-maximal and maximal exercise?


  Sub-maximal is low-to-moderate intensity, while maximal is high intensity above aerobic capacity
• What is venous return?


  The return of blood to the right atrium through the veins
• What is the typical resting value for stroke volume in a trained individual?


  100 ml
• What is the typical resting heart rate for a trained individual?


  50 bpm
• What is the typical resting cardiac output for a trained individual?


  5 l/min
• What is the role of the cardiovascular system during exercise?


  To increase oxygenated blood flow to the muscles
• How does the cardiovascular system respond to increased demand for oxygen during exercise?


  By increasing heart rate and stroke volume
• What is the significance of the cardiac cycle?


  It refers to cardiac muscle contraction and the movement of blood through its chambers
• How long does a complete cardiac cycle take at rest?


  Approximately 0.8 seconds
• What occurs during diastole?


  Relaxation of the atria and ventricles, allowing blood to flow into the ventricles
• What occurs during systole?


  Atria contract, forcing blood into the ventricles, followed by ventricular contraction