L4.2.5: Heart Valves

• HEART VALVES

  ● 4 valves that allow blood to flow in only one direction to prevent backflow

  ● Valves open and close in response to pressure changes in the heart

  ● CHORDAE TENDINEAE — tendinous cord; heart strings that connect papillary muscles to the valves
• TWO TYPES OF VALVES

  • ATRIOVENTRICULAR (AV) VALVES
  • SEMILUNAR VALVES
• ATRIOVENTRICULAR (AV) VALVES

  • Between atria and ventricles
  • Open during heart relaxation, when blood passively fills the chambers
  • Closed during ventricular contraction
  • Anchor the cusps in place by chordae tendineae to the walls of the ventricles
  • Bicuspid / Mitral Valve , Tricuspid Valve
• SEMILUNAR VALVES

  • Between atria and ventricles Between the ventricle and artery
  • Closed during heart relaxation
  • Open during ventricular contraction
  • Pulmonary Valve , Aortic Valve
• 4 VALVES OF THE HEART: “Try Pulling My Aorta”

  • Mitral / Bicuspid
  • Tricuspid
  • Pulmonary
  • Aortic
• Mnemonic for the 2 AV valves

  “LAB RAT”

  Left Atrium: Bicuspid, Right Atrium: Tricuspid
• Mitral / Bicuspid

  Consists of 2 flaps/cusps of the endocardium
• Tricuspid

  Consists of 3 cusps of endocardium
• Pulmonary

  Leads deoxygenated blood to the lungs
• Aortic

  Leads oxygenated blood to the body

  Both Pulmonary and Aortic consist of 3 flaps