What are capillaries?

The the smallest blood vessels is called the capillaries. Gray's Anatomy (1918) describes it as the smallest blood vessels in the body.

What it is

  • The smallest blood vessels in the body.
  • Their walls are only a single cell thick.
  • The site where oxygen, nutrients, and waste products are exchanged between blood and tissue.

Where it is

  • Form dense networks (capillary beds) within every tissue.
  • Connect the smallest arteries (arterioles) to the smallest veins (venules).
  • Nearly every cell in the body lies within a fraction of a millimeter of a capillary.

Source:

Last verified: 2026-07-18

  • Best Anatomy Answers is an educational reference about human anatomy. It is not medical advice — for any health concern, talk to a licensed medical professional.

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