Question

explain peristalsis ?

Answer 1

A time-space diagram of a peristaltic wave after a water swallow. High pressure values are red, zero pressure is blue-green. The ridge in the upper part of the picture is the high pressure of the upper esophageal sphincter which only opens for a short time to let water pass.

Peristalsis is a radially symmetrical contraction and relaxation of muscles that propagates in a wave down a tube, in an anterograde direction.

In much of a digestive tract such as the human gastrointestinal tract, smooth muscle tissue contracts in sequence to produce a peristaltic wave, which propels a ball of food (called a bolus while in the esophagus and upper gastrointestinal tract and chyme in the stomach) along the tract. Peristaltic movement comprises relaxation of circular smooth muscles, then their contraction behind the chewed material to keep it from moving backward, then longitudinal contraction to push it forward.

Earthworms use a similar mechanism to drive their locomotion,[1] and some modern machinery imitates this design.

Answer 2

The involuntary constriction and relaxation of the muscles of the intestines or another canal, creating wave like movements which push the content of the canal forward is known as peristalsis.
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