The Heart

• Since the heart is a muscle tissue that initiates its own contractions rather than by nerve impulses, it is referred to as myogenic
• Define Myogenic:

  Describes cardiac muscle tissue that initiates its own contractions rather than by nerve impulses
• State the features of the mammalian heart:

  1. Superior vena cava
  2. Inferior vena cava
  3. Right atrium
  4. Right atrio-ventricular valve
  5. Right ventricle
  6. Semilunar valve
  7. Pulmonary artery
  8. Pulmonary vein
  9. Left atrium
  10. Left atrio-ventricular valve
  11. Left ventricle
  12. Aortic valve
  13. Aorta
  14. Septum

  On the surface: Coronary artery

  
• The right atrio-ventricular valve is also called...

  Tricuspid valve
• The left atrio-venticular valve is also called...

  Bicuspid valve
• Define Myocardium:

  The muscle found in the walls of the heart
• Define Coronary Arteries:

  The arteries on the surface of the heart
• What is the function of the tendinous cords?

  to prevent the atrio-venticular valves from turning inside out when the walls contract
• Which muscles in the ventricle wall are the tendinous cords connected to?

  Papillary muscles
• Define Septum:

  The wall of muscle that separates the left side and the right side of the heart
• What is the function of the septum in the heart?

  to separate the left side and the right side of the heart, preventing oxygenated and deoxygenated blood from mixing
• Which side of the heart is the thickest?

  Left
• Why is the wall of the left side of the heart thicker than the right?

  • the left ventricle needs to apply more force
  • it pumps the blood at a further distance (around the body) against greater resistance
• Through which blood vessel does deoxygenated blood leave the heart?

  Pulmonary artery
• Through which blood vessel does oxygenated blood enter the heart?

  Pulmonary vein
• Through which blood vessel does oxygenated blood leave the heart?

  Aorta
• What is the function of the valves?

  to prevent the backflow of blood
• The higher the pressure created in the heart, the further it will push the blood
• The aortic valve is also called the...

  semilunar valve
• Which walls are thicker, the atria (R/L atrium) or the ventricles?

  Ventricles
• The right ventricle pumps deoxygenated blood to the lungs for gas exchange
• Why are the walls of the atria very thin?

  • they do not pump blood at a further distance (to the ventricles)
  • they receive blood
  • ∴ they do not need to generate high pressure
  • ∴ they do not need to be muscular
• Why shouldn't oxygenated and deoxygenated blood mix?

  to increase the efficiency of gas exchange
• Blood flows from high pressure to low pressure
• Formula for cardiac output:

  stroke volume x heart rate
• State three arteries that can be seen on a human heart without dissection:

  • Aorta
  • pulmonary artery
  • coronary arteries
• Give two risk factors for increasing the chance of developing heart disease:

  • Smoking
  • Obesity
  • High fatty or salty diet
  • High blood pressure