Lecture Notes: Mammalian Circulatory System

Introduction

• The lecture discusses the transport system in complex multicellular organisms.
• Key components: heart, blood vessels, and blood.
• Purpose: To minimize diffusion distance and ensure cells receive necessary substances like oxygen.

The Heart and Blood Circulation

• Heart: Acts as a pump to generate pressure and push blood throughout the body.
• Function of Blood:
  • Carries oxygen and other substances.
  • Appears red due to specific components (to be discussed later).
  • Must remain in liquid form to function effectively.

Blood Vessels

• Blood needs containment: utilizes blood vessels.
• Blood vessels prevent blood from leaking out while allowing oxygen to diffuse to cells.
• Oxygen is delivered to cells; CO2, a waste product, is returned to blood to be expelled.

Oxygenation Process

• Blood returns to the heart and is then pumped to the lungs, specifically the alveolus.
• In the alveolus:
  • Oxygen diffuses into blood.
  • Carbon dioxide diffuses out into alveoli for expulsion.
• Oxygenated blood returns to the heart and is distributed to the body.

Circulatory System

• Closed Double Circulatory System:
  • Blood remains in vessels, preventing hemorrhage.
  • Blood passes through the heart twice per complete circulation.
• Pulmonary Circulation:
  • Blood travels from heart to lungs and back.
  • Purpose: Oxygenate deoxygenated blood.
• Systemic Circulation:
  • Blood travels from heart to body and back.
  • Purpose: Deliver oxygen and nutrients to body cells.

Summary

• Mammalian circulatory system ensures efficient delivery of oxygen and nutrients.
• Consists of two main circulations: pulmonary (lungs) and systemic (rest of the body).
• Emphasizes maintaining blood within vessels to prevent leakage and ensure effective circulation.