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Understanding Heart Anatomy and Function

Mar 2, 2025

Anatomy of the Heart: Key Concepts

Overview

  • The heart functions as two separate pumps, each side working independently.
  • The anatomical path is similar for both sides, starting from the atria, passing through atrioventricular (AV) valves, into the ventricles, and then out through semilunar valves.

Heart Structure

  • Atria: Smaller upper chambers of the heart.
  • AV Valves:
    • Right AV Valve: Tricuspid Valve
    • Left AV Valve: Bicuspid or Mitral Valve
  • Ventricles: Larger inferior chambers of the heart.
  • Semilunar Valves: Pulmonary and Aortic Valves

Circulatory Circuits

  • Pulmonary Circuit (Right Side):
    • Handles deoxygenated blood, directing it to the lungs.
    • Collects dirty blood from the body via the superior and inferior vena cavae.
  • Systemic Circuit (Left Side):
    • Distributes oxygenated blood to the body.
    • Receives blood from the lungs via pulmonary veins.

Blood Flow Pathway

  1. Deoxygenated blood returns to the right atrium via superior and inferior vena cavae.
  2. Blood moves to the right ventricle through the tricuspid valve.
  3. Blood is pumped to the lungs via the pulmonary artery through the pulmonary valve.
  4. Oxygenated blood returns from the lungs to the left atrium.
  5. Blood moves to the left ventricle through the mitral valve.
  6. Blood is pumped to the body via the aorta through the aortic valve.

Heart Valves Function

  • Ensure one-directional blood flow.
  • Chordae Tendineae: Prevent valve inversion by anchoring to the papillary muscles.
  • Mitral Valve Prolapse: A dangerous condition on the left side preventing oxygenated blood circulation.
  • Heart Murmurs: Occur due to leaky or stenotic valves; usually non-life-threatening.

Major Blood Vessels

  • Superior Vena Cava: Collects blood from the upper body.
  • Inferior Vena Cava: Collects blood from below the diaphragm.
  • Coronary Sinus: Drains deoxygenated blood from the heart muscle itself.

Important Points

  • Blood is never blue; it is either bright red (oxygenated) or dark red (deoxygenated).
  • Arteries carry blood away from the heart, while veins carry blood towards the heart.

Additional Anatomy Notes

  • Aortic Arch Branches: Brachiocephalic, Carotid, and Subclavian arteries ("BCS").
  • Aorta: Largest artery, branches into smaller arteries, arterioles, capillaries, venules, veins, and back to vena cavae.
  • Heart Muscle: The myocardium is thicker on the left side to pump blood throughout the body.
  • Be familiar with the flow of blood through the heart for understanding anatomy and physiology.