Lecture on Heart Valves

Overview

• Function: Heart valves ensure unidirectional blood flow through the heart.
• Mechanism: Open and close in response to pressure changes.

Types of Heart Valves

1. Atrioventricular Valves (AV Valves)

   • Located between atria (receiving chambers) and ventricles (pumping chambers).
   • Types:
     • Tricuspid Valve: Between right atrium and right ventricle.
     • Bicuspid Valve (Mitral Valve): Between left atrium and left ventricle.

2. Semilunar Valves

   • Located between ventricles (pumping chambers) and major arteries.
   • Types:
     • Pulmonary Valve: Between right ventricle and pulmonary trunk.
     • Aortic Valve: Between left ventricle and aorta.

Detailed Examination of Valves

Atrioventricular Valves

• Tricuspid Valve:
  • Right side of the heart.
  • Made up of three cusps.
• Bicuspid (Mitral) Valve:
  • Left side of the heart.
  • Made up of two cusps.
• Chordae Tendineae:
  • Anchor valve cusps to papillary muscles.
  • Prevent cusps from everting back into atria.

Functioning of AV Valves

• Blood filling atria presses against AV valve, increasing pressure, and forcing it open.
• Ventricles fill, and AV valve flaps hang limply.
• Atria contraction forces additional blood into ventricles.

Semilunar Valves

• Structure:
  • Consist of three cusps resembling a half-moon.
• Pulmonary Valve:
  • Between right ventricle and pulmonary trunk.
• Aortic Valve:
  • Between left ventricle and aorta.

Functioning of Semilunar Valves

• Ventricular contraction increases intraventricular pressure, pushing blood against semilunar valves and forcing them open.
• As ventricles relax, blood flows back from arteries, filling cusps and forcing valves to close.

Summary

• Both valve types are critical in preventing backflow and ensuring efficient heart function through unidirectional blood flow, adapting to pressure changes in the heart.