Motility in Alimentary Canal Food is moved through digestive tracts by cilia or by specialized musculature, and often by both. Movement is usually by cilia in acoelomate and pseudocoelomate metazoa that lack the mesodermally derived gut musculature of true coelomates. Cilia move intestinal fl uids and materials also in some eucoelomates, such as most molluscs, in which the coelom is weakly developed. In animals with well-developed coeloms, the gut is usually lined with two opposing layers of smooth muscle: a longitudinal layer, in which smooth muscle fibers run parallel with the length of the gut, and a circular layer, in which muscle fi bers embrace the circumference of the gut . A characteristic gut movement is   segmentation,   the alternate constriction of rings of smooth muscle of the intestine that constantly divide and squeeze contents back and forth …

Don’t forget to follow us on facebook, twitter, LinkedIn, tumblr and email for more updates….