Understanding the Human Heart's Functionality

Oct 7, 2024

Human Heart: The Incredible Pump

General Overview

  • The human heart is often called the hardest working organ in the body.
  • Functions as a pump that starts at approximately 8 weeks of fetal development and continues until death.

External and Internal Structure

  • External View: Shows the heart with vessels entering and leaving.
  • Internal View: A diagram is used to follow the path of blood through the heart.

Circulatory Pathway

Blood Entering the Heart

  • Blood returns from the body to the heart via veins.
  • Veins from arms and head converge into the superior vena cava entering the top of the heart.
  • Veins from legs and lower body converge into the inferior vena cava joining the heart.

Heart Chambers and Valves

  1. Right Atrium
    • Blood enters from the superior and inferior vena cavae.
  2. Right Ventricle
    • Blood passes from the right atrium through the tricuspid valve.
      • The tricuspid valve has three flaps, preventing backflow.
    • Blood exits the right ventricle through the pulmonary valve.
  3. Lungs
    • Blood travels from the heart to the lungs via the right and left pulmonary arteries.
    • Blood picks up oxygen (O2) and releases carbon dioxide (CO2) in the lungs.
    • Blood changes from deoxygenated (blue) to oxygenated (red).
  4. Left Atrium
    • Oxygenated blood returns to the heart from the lungs.
  5. Left Ventricle
    • Blood passes from the left atrium through the mitral valve.
    • Exits through the aortic valve into the aorta.

Major Vessels

  • Aorta: Largest artery that distributes oxygenated blood to the body.
  • Pulmonary Arteries: Carry deoxygenated blood from the heart to the lungs.

Function of Valves

  • Ensure unidirectional blood flow.
  • Prevent backward blood flow.
    • Tricuspid Valve: Between right atrium and right ventricle.
    • Pulmonary Valve: Between right ventricle and pulmonary arteries.
    • Mitral Valve: Between left atrium and left ventricle.
    • Aortic Valve: Between left ventricle and aorta.

Summary of Blood Flow

  1. Blood flows from the body to the right atrium.
  2. Moves to the right ventricle, then to the lungs via pulmonary arteries.
  3. Returns oxygenated to the left atrium.
  4. Moves to the left ventricle, exits via aorta to the rest of the body.

This cycle occurs continuously, ensuring blood is delivered throughout the body and supporting cellular functions.