Cardiovascular (4)

• The heart beat (part 1)


  1. Blood from body enters right atrium through vena cava

  2. Blood trickles into right ventricle

  3. Tricuspid valves close once pressure inside ventricle is higher than atrium
• The heart beat (part 2)


  1. Right ventricle contracts from base and semilunar valves open to push blood to lungs

  2. Blood enters left atrium through pulmonary vein and forces bicuspid valve to open to enter left ventricle

  3. Contraction happens and blood is forced into aorta to body
• Ca2+


  Key to contraction
• Inotropy


  Contractility of the heart
• Preload


  Initial stretching of cardiac myocytes prior to contraction, related to sarcomere length
• Starling's Law of the Heart


  Ventricular diastolic end-volume is controlled by ventricular filling pressure, central venous filling pressure, and venous return