Cardiovascular System Physiology 200 Level (MBBS)

Overview of the Cardiovascular System

• Central components: heart (pump) and vasculature (blood vessels) for blood distribution.
• Core functions include collection and distribution of blood, transporting oxygen and nutrients, and removing waste products.

The Functional Anatomy of the Heart

• Muscular organ responsible for pumping blood throughout the circulatory system.
• Dimensions: approximately 12 cm in length and 9 cm in breadth, resembling a closed fist.
• Average weight is around 250 grams.
• Located between the lungs in the mediastinum, resting on the diaphragm, positioned ⅔ to the left of the midline.

The Wall of the Heart

• Composed of three main layers: pericardium, myocardium, and endocardium.

Pericardium

• Outer Parietal Pericardium:

  • Strong protective sac that anchors the heart in the mediastinum.
  • Composed of two layers: outer fibrous layer and inner serous layer.

• Inner Viscera Pericardium (Epicardium):

  • Lines the surface of the myocardium, composed of flattened epithelial cells.

Outer Fibrous Layer

• Made of thick fibrous connective tissue with inelastic fibers.
• Protects the heart from overstretching and is continuous with the outer wall (tunica adventitia) of entering and exiting blood vessels.

Inner Serous Layer

• Composed of mesothelium with squamous epithelial cells.
• Secretes a small amount of fluid to reduce friction during heart movement.

Functions of the Pericardium

• Protects and anchors the heart.
• Prevents overfilling of the heart with blood.
• Allows for friction-free movement of the heart during contraction and relaxation.

Chambers of the Heart

• Left Side:

  • Comprises the left atrium (LA) and left ventricle (LV).

• Right Side:

  • Comprises the right atrium (RA) and right ventricle (RV).