PCB 2061L Study Guide - Quiz Guide: Esophagus, Pylorus, Tetanic Contraction
Document Summary
Carries information to the lower parts of the large intestine and pelvic organs. Contraction of the circular muscle leads to a decrease in diameter of that segment of the gi tract. Contraction of the longitudinal muscle leads to a decrease in length of that segment of the gi tract. Phasic contraction are found in esophagus, gastric antrum, and small intestine which contract and relax periodically. Tonic contraction are found in lower esophageal sphincter, the orad stomach, and the ileocecal and internal anal sphincters. *are oscillating membrane potentials inherent to the smooth muscle cells of some parts of the. *they originate in the interstitial cells of cajal, which serve as the pacemaker for gi smooth muscle. *they are not action potentials, although they determine the pattern of action potentials and, therefore, the pattern of contraction. *varies along the gi tract, but is constant in each part. *is not influenced by neuronal or hormonal input.
