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Where does tissue fluid go when it becomes lymph?

Fluid around cells can enter tiny lymphatic vessels and begin a route back toward the blood. Once inside, it is called lymph. Valves help direct its movement, while muscle activity, breathing, and vessel-wall contractions contribute forces that move it along.

5–7 min

Questions you could explore

  • Why is a one-way valve different from a pump?

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2–3 min

Why won’t an antibiotic treat a viral cold?

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