Lecture Notes on the Heart Anatomy

Introduction

• The heart is a hollow muscular organ located in the thoracic cavity.
• This session covers basic anatomical terminology and structures of the heart.
• Importance of understanding perspective in anatomy (left vs. right side orientation).

Main Chambers of the Heart

• The heart consists of four chambers:
  • Ventricles (bottom chambers):
    • Left Ventricle: Thick muscular wall, pumps blood to systemic circulation.
    • Right Ventricle: Thinner muscular wall, pumps blood to lungs.

Function of the Ventricles

• Left Ventricle:
  • Pumps oxygenated blood to the body, generating high pressure for systemic circulation.
• Right Ventricle:
  • Pumps deoxygenated blood to the lungs, requiring lower pressure.

Valves of the Heart

• Valves control blood flow direction:
  • Atrioventricular Valve (between atria and ventricles):
    • Left atrioventricular valve (Mitral/Bicuspid valve) has two cusps.
  • Aortic Valve:
    • Connects left ventricle to aorta, part of systemic circulation.
  • Pulmonary Valve:
    • Connects right ventricle to pulmonary artery, sending blood to the lungs.
  • Tricuspid Valve:
    • Right atrioventricular valve with three cusps.

Major Vessels

• Pulmonary Veins: Carry oxygenated blood from lungs to left atrium.
• Superior and Inferior Vena Cava:
  • Drain deoxygenated blood from the body into the right atrium.
• Pulmonary Artery: Carries deoxygenated blood from the right ventricle to the lungs.
• Aorta: Carries oxygenated blood from the left ventricle to the body.

Blood Flow Through the Heart

1. Blood returns from lungs via pulmonary veins (oxygenated).
2. Enters left atrium → through mitral valve → left ventricle.
3. From left ventricle → through aortic valve → aorta → systemic circulation.
4. Deoxygenated blood returns via superior/inferior vena cava → enters right atrium.
5. From right atrium → through tricuspid valve → right ventricle.
6. From right ventricle → through pulmonary valve → pulmonary artery → to lungs.

Supporting Structures

• Tendinous Cords (Chordae Tendineae):
  • Prevent valves from over-expanding.
• Connected to the heart wall by papillary muscles.

Heart Layers

• Pericardium: Fibrous sack providing physical protection and limiting over-expansion.
• Endocardium: Thin layer of endothelial cells lining the heart's inside, ensuring smooth blood flow.
• Myocardium: Thick muscular layer responsible for heart contractions.

Septum

• Cardiac Septum: Structure that separates the left and right sides of the heart.

Summary of Functions

• Left Side of the Heart: Body pump (systemic circulation).
• Right Side of the Heart: Lung pump (pulmonary circulation).

Conclusion

• Understanding the basic anatomy of the heart is essential for studying its function and blood flow.