Notes on the Circulatory System

Overview of the Circulatory System

• Organ system responsible for transporting oxygen and nutrients to body tissues.
• Relies on three main components:
  • Blood: Carries oxygen and nutrients.
  • Blood Vessels: Hold and transport blood.
  • Heart: Pumps blood through the vessels.

Structure of the Heart

• The heart consists of four chambers:
  • Atria (top chambers):
    • Left Atrium (on the right side of the diagram).
    • Right Atrium (on the left side of the diagram).
  • Ventricles (bottom chambers):
    • Left Ventricle
    • Right Ventricle
• Valves between chambers and vessels prevent backflow of blood.

Blood Circulation Pathway

1. Blood Inflow to Heart:
   • Blood enters via Vena Cava (deoxygenated) and Pulmonary Vein (oxygenated).
2. Atria Contraction:
   • Blood is pushed from the atria into the ventricles.
3. Ventricles Contraction:
   • Blood is pumped out to:
     • Pulmonary Artery (to lungs)
     • Aorta (to rest of the body)
4. Cycle Frequency:
   • This cycle repeats approximately 70 times per minute, over 100,000 times daily.

Pacemaker of the Heart

• Pacemaker cells in the Right Atrium generate electrical impulses to regulate heart contractions.
• An artificial pacemaker can be implanted if natural pacemaker cells malfunction.

Understanding Arteries and Veins

• Arteries: Vessels that carry blood away from the heart.
  • Example: Pulmonary Artery (carries deoxygenated blood).
• Veins: Vessels that carry blood to the heart.
  • Example: Pulmonary Vein (carries oxygenated blood).

Coronary Arteries

• Coronary arteries branch off the aorta to supply the heart muscle with oxygenated blood.

Conclusion

• Importance of understanding the heart's structure and function.
• Encourage sharing knowledge with peers.