Anatomy of the Heart and Pericardium

Overview of the Heart's Membranes

• The heart is surrounded by a serous membrane known as the pericardium.
  • "Peri-" means around, "-cardium" refers to the heart.
• The pericardium is a double-layered membrane.

Layers of the Heart Wall

• Epicardium:
  • Also known as the visceral layer of the serous pericardium.
  • The outermost layer of the heart wall.
• Myocardium:
  • Middle layer, the thickest part of the heart wall.
  • Composed mainly of cardiac muscle cells, blood vessels, and connective tissue.
  • "Myo-" means muscle; it is the muscular part of the heart.
• Endocardium:
  • Innermost layer of the heart wall.
  • "Endo-" means within.

Functions of the Pericardium

• Stabilizes, protects, and anchors the heart.
• Prevents the heart from overexpanding when filled with blood.
• Composed of tough, strong material.

Structure of the Pericardium

• Analogy: The heart is like a fist pressed into a balloon.
  • Fibrous Pericardium: Outermost layer, tough and strong.
  • Serous Pericardium: Divided into two layers:
    • Parietal Layer: Outer layer, part of the fibrous pericardium.
    • Visceral Layer: Inner layer, directly wraps around the heart (epicardium).
• Pericardial Cavity:
  • Space between the parietal and visceral layers.
  • Contains pericardial fluid.

Pericardial Fluid

• A serous fluid that reduces friction between the heart and pericardium.
• Acts as a lubricant to prevent wear during the heart's constant movement.

Diseases Related to the Pericardium

• Pericarditis:
  • Inflammation of the pericardium, often due to infection.
  • Symptoms include pain and a scratching sound upon auscultation.
  • Can cause the pericardial cavity to swell, leading to restricted heart movement.
• Cardiac Tamponade:
  • Occurs when excess pericardial fluid accumulates, restricting heart function.
  • Fluid build-up prevents the heart from expanding and pumping blood normally.