Biology / Unit 13 Bio 3081 short lesson, about 20 seconds
Hydrostatic Skeleton Mechanism
Captions available
The idea
A hydrostatic skeleton supports a soft body using fluid held under pressure inside a body cavity, against which surrounding muscles contract to change shape and move.
In practice
An earthworm shortens and lengthens segments by contracting circular and longitudinal muscles against its fluid-filled coelom.
Where people slip
A hydrostatic skeleton needs no rigid material at all — the fluid itself does the resisting.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
- Nothing. This is a starting point.
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