Pulmonary Circulation Lecture Notes

Overview

• Purpose of Pulmonary Circulation
  • Transport deoxygenated blood from the right side of the heart to the lungs.
  • Oxygenate the blood in the lungs by picking up oxygen and releasing carbon dioxide (CO2).
  • Deliver oxygenated blood to the left side of the heart.

Detailed Pathway

1. Right Ventricle

   • Starting point of pulmonary circulation.
   • Functions as the pump driving the circulation.

2. Pulmonary Semilunar Valve

   • Blood is pumped from the right ventricle through this valve.

3. Pulmonary Trunk

   • Blood enters the pulmonary trunk after passing through the semilunar valve.

4. Pulmonary Arteries

   • Pulmonary trunk splits into right and left pulmonary arteries.
   • Note: These arteries carry deoxygenated blood, depicted as blue.

5. Pulmonary Arterioles

   • Smaller branches from the pulmonary arteries.
   • High resistance vessels controlling constriction and dilation.

6. Pulmonary Capillaries

   • Site of gas exchange.
   • Function: Oxygen is picked up, and CO2 is dropped off.
   • Occurs in structural units called alveoli.

7. Pulmonary Venules

   • Small veins collecting oxygenated blood from capillaries.

8. Pulmonary Veins

   • Formed by the confluence of pulmonary venules.
   • Carry oxygenated blood back to the heart.
   • Depicted as red to indicate the presence of oxygen.

9. Left Atrium

   • Receives oxygenated blood from the pulmonary veins.

10. Mitral/Bicuspid Valve

    • Blood is pushed through this valve from the left atrium.

11. Left Ventricle

    • Final chamber in pulmonary circulation.
    • Prepares blood for systemic or coronary circulation.

Key Concepts

• Arteries vs. Veins:
  • Arteries carry blood away from the heart, veins bring blood back to the heart.
  • Pulmonary arteries are an exception, carrying deoxygenated blood.
• Gas Exchange:
  • Occurs in pulmonary capillaries with alveoli.
  • Essential for oxygen uptake and CO2 removal.

Conclusion

• Pulmonary circulation is essential for oxygenating blood and removing CO2.
• Right ventricle drives pulmonary circulation, while the left ventricle prepares blood for further systemic distribution.
• Repetition is key for memorizing the flow and functions of pulmonary circulation.