the structure of the heart

• external structure -

  A) pulmonary artery

  B) left atrium

  C) pulmonary veins

  D) left ventricle

  E) inferior vena cava

  F) right ventricle

  G) coronary artery

  H) right atrium

  I) aorta

  J) superior vena cava

  
• internal structure -

  A) superior vena cava

  B) inferior vena cava

  C) atrioventricular valve

  D) right ventricle

  E) semilunar valve

  F) right atrium

  G) pulmonary artery

  H) pulmonary veins

  I) left atrium

  J) atrioventricular valve

  K) cords ( valve tendons )

  L) left ventricle

  M) semilunar valve

  N) aorta

  
• the right side of the heart pumps deoxygenated blood
• the left side of the heart pumps oxygenated blood
• valves prevent backflow of blood
• atrioventricular valves link the atria to the ventricles
• the semi-lunar valves link the ventricles to the pulmonary artery and aorta
• 1. valves open only one way whether there opened or closed depends on the relative pressure of the heart chambers
  2. if there is a higher pressure behind a valve, its forced open
  3. if pressure is higher in front of a valve, its forced shut