Lecture Notes: Blood Flow and Heart Valves

Overview of Heart Anatomy and Function

• Heart Views:
  • Superior view with atria removed
  • Anterior view
• Function:
  • Heart valves act as one-way valves to ensure proper blood flow.
  • Valves involved: atrioventricular (AV) valves, aortic valve, pulmonary semilunar valve.

Blood Flow Process

• Ventricular Relaxation:
  • Blood flows from atria to ventricles via open AV valves.
  • Aortic and pulmonary valves are closed to allow ventricle filling without backflow.
• Ventricular Contraction:
  • AV valves close due to increased pressure.
  • Ventricles contract, opening aortic and pulmonary valves allowing blood to flow into arteries.
  • Papillary muscles and chordae tendineae prevent AV valve cusps from inverting into atria.

Heart Valve Diseases

• Types and Causes:
  • Heart valve disease often due to aging, genetics, metabolic factors (e.g., diabetes, high LDL cholesterol), and lifestyle.
  • Can be congenital or develop from infections, medical treatments, or lifestyle.

Types of Valve Malfunctions

• Stenosis:
  • Valve doesn't open fully, reducing blood flow.
  • Causes: calcification, congenital defects, genetic diseases, inflammation, infections, medical treatments.
• Regurgitation:
  • Valve doesn't close properly, allowing backward blood flow.
  • Causes: prolapse, congenital defects, infections, heart attacks, hypertension.

Heart Sounds

• Normal vs. Abnormal:
  • Normal sounds: "lub-dub"
  • Abnormal sounds (murmurs): often due to regurgitation; may create hissing or whooshing sounds.
  • Innocent murmurs may occur with no underlying heart issues.

Prolapsed Valve and Regurgitation

• Prolapse:
  • Often affects the mitral valve (left AV valve).
  • Valve cusps pushed into atrium, don't seal properly, causing regurgitation.
  • Blood leaks back into the left atrium during ventricular contraction.