Circulatory System

Key Notes :

1. What is the Circulatory System?

  • The circulatory system is a network of blood vessels and organs that transport blood, nutrients, gases (like oxygen and carbon dioxide), and waste products throughout the body.
  • It consists of the heart, blood vessels, and blood.

2. Main Parts of the Circulatory System:

  • Heart: A muscular organ that pumps blood throughout the body.
    • Left side: Pumps oxygenated blood to the body.
    • Right side: Pumps deoxygenated blood to the lungs.
  • Blood Vessels: Tubes that carry blood throughout the body.
    • Arteries: Carry oxygenated blood away from the heart to the body (except the pulmonary artery).
    • Veins: Carry deoxygenated blood back to the heart (except the pulmonary vein).
    • Capillaries: Tiny blood vessels that connect arteries and veins, allowing exchange of gases, nutrients, and waste.
  • Blood: Fluid that carries nutrients, oxygen, and waste products.
    • Red Blood Cells (RBCs): Carry oxygen from the lungs to the body and return carbon dioxide from the body to the lungs.
    • White Blood Cells (WBCs): Help fight infections and diseases.
    • Platelets: Help in blood clotting to prevent excessive bleeding.
    • Plasma: The liquid component of blood, transporting nutrients, hormones, and waste products.

3. Function of the Circulatory System:

  • Transportation: Delivers oxygen and nutrients to cells and removes waste products like carbon dioxide and urea.
  • Temperature Regulation: Helps maintain body temperature by distributing heat throughout the body.
  • Protection: Blood carries immune cells that protect the body from infections and diseases.
  • Hormone Transport: Blood carries hormones from glands to target organs for regulation of bodily functions.

4. How the Heart Works:

  • The heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers).
  • Deoxygenated blood flows from the body into the right atrium, through the right ventricle, and is pumped to the lungs for oxygenation.
  • Oxygenated blood returns from the lungs to the left atrium, flows into the left ventricle, and is pumped to the rest of the body.

5. Blood Circulation Pathways:

  • Systemic Circulation: Movement of oxygenated blood from the heart to the body and back to the heart with deoxygenated blood.
  • Pulmonary Circulation: Movement of deoxygenated blood from the heart to the lungs and back, where it is oxygenated.

6. Circulatory System and Health:

  • Healthy Lifestyle: Regular exercise, balanced diet, and avoiding smoking help maintain a healthy circulatory system.
  • Common Diseases:
    • Atherosclerosis: Build-up of plaque in arteries, reducing blood flow.
    • Hypertension: High blood pressure can damage blood vessels and the heart.
    • Heart Attack: Occurs when blood flow to a part of the heart is blocked.

7. Fun Fact:

  • The human circulatory system, if laid out end to end, would stretch for about 100,000 kilometers!

Let’s practice!