Cardiac Muscle Anatomy Quiz for 2nd-Year Students

Cardiac Structure and Composition

• The heart is enclosed in a protective fibrous sac called the pericardium.
• The wall of the heart is composed primarily of cardiac muscle and connective tissue.
• Cardiac muscle, a type of muscle found only in the heart, is striated and branching.
• The striated appearance of cardiac muscle is due to the presence of sarcomeres and T-tubules.
• Individual cardiac muscle cells are approximately 10-15 μm in diameter and 50-100 μm in length.
• The thin layer of cells lining the inner surface of the cardiac chambers and blood vessels is called the endothelium.
• The watery fluid filling the space between the pericardium and the epicardium, known as pericardial fluid, reduces friction between the two layers.
• The epicardium is a fibrous layer closely affixed to the heart.
• Actin and tropomyosin are proteins present in the thin filaments of cardiac muscle cells, with functions similar to those in skeletal muscle.