Biology / Unit 13 Bio 3197 short lesson, about 20 seconds
Heart Chambers and Valves
Captions available
The idea
A mammalian heart has four chambers — two atria receiving blood, two ventricles pumping it out — separated by valves enforcing one-directional flow.
In practice
The mitral valve stops blood flowing backward from left ventricle into left atrium during contraction.
Where people slip
A failing valve lets blood leak backward while chamber structure stays intact — distinct problems.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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