Blood vessels

 

There are three different types of blood vessels:

 

• Arteries - carry blood away from the heart.
• Capillaries - where gas exchange takes place.
• Veins - carry blood to the heart.

 

Arteries

• Carry blood away from the heart.

• Have thick walls composed largely of muscle and elastic tissue.

• Have small passageways for blood (internal lumen).

• Contain blood under high pressure.

 

 

Veins

 

• Carries blood back to the heart.

• Have thin walls.

• Have larger passageways for blood (internal lumen).

• Contain blood under low pressure.

• Contain valves which stop the blood flowing the wrong way .

 

 

Capillaries

 

• Found in the muscles and lungs.
• Walls are one cell thick to allow substances to pass over.
• Very low blood pressure.
• Where gas exchange takes place - oxygen passes through the capillary wall and into the tissues, while carbon dioxide passes from the tissues into the blood.

 

Tags:Blood, vein, artery, arteries, capillaries, red blood cells white blood cells and platelets, red blood cell white blood cell and platelets