Blood Circulation and Vessels

Importance of Blood

• Supplies essential materials for the body to function and remain healthy
• Transports oxygen, nutrients, and waste products through blood vessels

Blood Vessels Overview

• Types of Blood Vessels: Arteries, Capillaries, Veins
• Each type has distinct functions in maintaining blood pressure and facilitating exchange of materials.

Arteries

• Carry blood away from the heart
• Blood contains nutrients and oxygen
• Example: Aorta transports oxygenated blood to the body
• Structure:
  • Thick muscular and elastic walls
  • Narrow lumen
  • High-pressure blood flow
  • No valves; situated deep under the skin
• Branches: Arteries branch into smaller arterioles which connect to capillaries

Capillaries

• Act as exchange centers in the circulatory system
• Tiny vessels, one cell thick
• Allow movement of oxygen, carbon dioxide, nutrients, and waste between blood and surrounding cells
• Located between arteries and veins
• Blood flow is at low pressure; no valves present
• Key Functions:
  • Receives oxygen and nutrients
  • Releases waste products
  • Found in areas like the liver and kidneys

Veins

• Carry deoxygenated blood back to the heart
• Transport carbon dioxide and other wastes
• Example: Pulmonary vein and vena cava
• Structure:
  • Thin walls with wide lumen
  • Low-pressure blood flow; valves present to prevent backflow
  • Located superficially on the skin
• Branches: Veins branch into smaller venules which connect to capillaries

Blood Flow Pathway

1. Artery (e.g., Aorta) transports blood away from the heart
2. Blood moves into Arterioles (smaller branches of arteries)
3. Blood flows through Capillary Beds (exchange occurs)
   • Nutrients and oxygen delivered; waste products collected
4. Blood containing waste moves into Venules (smaller branches of veins)
5. Blood is transported to the Vein (e.g., Vena Cava) back to the heart

This flow is essential for maintaining oxygen levels and removing waste from the body.