Anatomy · Circulatory system
Blood vessels: the circulatory system
A clear, referenced guide to the body's major blood vessels — the arteries that carry blood from the heart, the veins that return it, and the tiny capillaries where exchange happens, across 9 key vessels.
Arterys
Capillaries
Veins
No match — try another vessel name.
See also
Bones · Organs · Muscles · Nerves · Body systems
How to use this section
Structure, function, and what goes wrong
Each guide covers the vessel’s course, what it supplies or drains, and the consequences when it narrows, blocks or bleeds.
Vascular anatomy explains a great deal of acute medicine. Because most tissue is supplied by one main artery with limited backup, a blockage produces a predictable pattern of damage — which is why the territory of a blocked vessel maps so closely onto the symptoms of a stroke or a heart attack. Veins matter for the opposite reason: they are where clots tend to form before travelling, as in venous thromboembolism.
Anatomical descriptions rely on a small set of position words used precisely: proximal and distal, medial and lateral, anterior and posterior. They are always relative to the standard anatomical position, not to how a body happens to be lying. All are defined in our glossary, and appear as clickable definitions throughout these pages.
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