Medical Assistant Prep / Unit 4 MAS 078 short lesson, about 20 seconds
Arteries, Capillaries and Veins
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The idea
Blood travels from the heart through arteries, exchanges materials in capillaries, and returns through veins.
In practice
Arteries carry blood away from the heart; capillaries, the smallest vessels, exchange gases, nutrients and wastes with tissues; veins have thinner walls and carry blood back.
Where people slip
Veins depend on surrounding muscle activity to push blood home, which matters later for blood draws.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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