Circulatory System: Blood Vessels

Overview

• The circulatory system consists of the heart, blood vessels, and blood.
• Blood vessels include arteries, capillaries, and veins.

Arteries

• Function: Carry blood away from the heart.
• Structure and Function Relationship:
  • Experience high blood pressure due to proximity to the heart.
  • Have thick walls comprising:
    • Thick muscular layer for strength.
    • Thick elastic layer to allow stretching and recoiling.
  • The lumen (inner space of the vessel) is relatively narrow.

Capillaries

• Function: Exchange nutrients and oxygen with tissues, remove waste like carbon dioxide.
• Structure and Function Relationship:
  • Walls are one cell thick, allowing easy diffusion.
  • Permeable walls facilitate substance exchange.
  • Tiny lumen but collectively have a large cross-sectional area.
  • Blood pressure is much lower compared to arteries, allowing slow flow for exchange.

Veins

• Function: Carry blood back to the heart.
• Structure and Function Relationship:
  • Larger lumen compared to arteries and capillaries.
  • Thin walls with small layers of elastic fibers and smooth muscle due to low-pressure blood.
  • Possess valves to prevent backward blood flow, ensuring directed flow towards the heart.

Calculating Rate of Blood Flow

• Formula: Rate of blood flow = Volume of blood / Time
• Example:
  • 2560 ml of blood through the aorta in 8 minutes.
  • Rate = 2560 ml / 8 min = 320 ml per minute.

Additional Resources

• Check related videos on the heart and blood for comprehensive understanding.

Note: Make sure to watch linked videos for more detailed information on the heart and blood specifics.