Peristalsis
Videos
Peristalsis is a type of intestinal motility, characterized by radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, which is preceded by a simultaneous contraction of the longitudinal muscle and relaxation of the circular muscle in the lining of the gut.
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.
A simplified image showing Earthworm movement via peristalsis
Seta
Videos
In biology, setae are any of a number of different bristle- or hair-like structures on living organisms.
Setae on the foreleg of a mayfly
Close-up of the underside of a gecko's foot as it walks on vertical glass
Common house geckos mating on a vertical glass window and showing lamellae under the feet
Pointed setae protruding into the fertile surface tubes of the bracket fungus Phellinus gilvus. Click on image