Capillaries

Capillaries

1. Arterioles feed into networks of capillaries

   • The capillaries link the arterioles to the venules
   • BLOOD ENTERING THE CAPILLARIES IS OXYGENATED
     • BLOOD LEAVING CARRIES LESS OXYGEN AND MORE CARBON DIOXIDE

2. Capillaries are very small vessels that spread throughout the tissues of the body

   • They branch between cells, no cell is far away from a capillary
     • Substances can diffuse between cells and the blood quickly
     • Because the diameter of the capillaries is small blood travels slowly allowing more time for diffusion

3. STRUCTURE

   • Thin walls with no elastic fibers or muscle
     • Helps them fit between cells
   • Walls consist one one thin cell
     • Diffusion occurs at a faster rate
       • Oxygen and other molecules can quickly diffuse out
       • Carbon dioxide and waste molecules can quickly diffuse in

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