Lecture Notes on the Heart

Introduction to the Heart

• Hollow Muscular Organ: Empty from inside, made of muscles.
• Function: Pumps blood into the circulatory system.
• Size and Weight:
  • Length: 10 cm
  • Weight: Women - 225 grams, Men - 310 grams
• Location: In the thoracic cavity, in the mediastinum.
  • Position: Slightly tilted to the left.
• Base and Apex:
  • Base is upwards and apex is downwards.

Structure of the Heart

• Three Layers:
  1. Pericardium (Outer)
  2. Myocardium (Middle)
  3. Endocardium (Innermost)

Pericardium

• Outer Covering: Made of two layers - parietal and visceral.
• Function: Strong protection, prevents over-stretching.
• Fluid:
  • Pericardial fluid in the pericardial cavity
  • Prevents friction, allows free movement.

Myocardium

• Middle Layer:
  • Made of cardiac muscle fibers
  • Involuntary
  • Three types: Contractile unit, pacemaker, conductive system

Endocardium

• Innermost Layer:
  • Lines chambers and walls
  • Smooths blood flow

Interior of the Heart

• Chambers:
  • 2 Atria (Right and Left)
  • 2 Ventricles (Right and Left)
• Valves:
  • Tricuspid, Mitral, Pulmonary, Aortic
• Function: Ensures one-directional flow of blood

Blood Vessels

• Superior and Inferior Vena Cava: Bring deoxygenated blood
• Pulmonary Artery and Veins: Gas exchange in the lungs
• Aorta: Circulation of oxygenated blood in the body

Blood Flow

• Starting from deoxygenated blood turning into oxygenated blood
• Pulmonary circulation and systemic circulation

Blood Supply and Venous Drainage

• Arterial Supply: Right and left coronary arteries
• Venous Drainage: Coronary sinus

Note: These notes are intended for an in-depth understanding of the heart's structure, function, and the process of blood circulation.