Segmentation contractions

Segmentation contractions (or movements) are a type of intestinal motility.

Unlike peristalsis, which predominates in the esophagus, segmentation contractions occur in the large intestine and small intestine, while predominating in the latter. While peristalsis involves one-way motion in the caudal direction, segmentation contractions move chyme in both directions, which allows greater mixing with the secretions of the intestines. Segmentation involves contractions of the circular muscles in the digestive tract, while peristalsis involves rhythmic contractions of the longitudinal muscles in the GI tract. Unlike peristalsis, segmentation actually can slow progression of chyme through the system.

External links

Physiology: 6/6ch3/s6ch3_8 - Essentials of Human Physiology
Animation at colostate.edu
"Segmentation contraction" at Dorland's Medical Dictionary

Physiology of the gastrointestinal system

GI tract

Upper

Exocrine	Chief cells Pepsinogen Parietal cells Gastric acid Intrinsic factor Foveolar cells HCO₃⁻ Mucus Goblet cells Mucus

Processes	Swallowing Vomiting

Fluids	Saliva Gastric acid

Lower

Enteric nervous system

Endocrine/paracrine

G cells gastrin D cells somatostatin ECL cells Histamine

enterogastrone:	I cells CCK K cells GIP S cells secretin

Enteroendocrine cells Enterochromaffin cell APUD cell

Fluids

Intestinal juice

Processes

Either/both

Processes	Peristalsis (Interstitial cell of Cajal Basal electrical rhythm) Gastrocolic reflex Digestion

Accessory

Fluids	Bile Pancreatic juice

Processes	Enterohepatic circulation

Abdominopelvic

Peritoneal fluid

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