Drug - Muscle Relaxants, Analgesics, Stimulants | Britannica
Prostaglandins E1 and E2 are dilators, and prostaglandins of the F series are bronchoconstrictors. Prostaglandin E1 also ... Prostanoids (e.g., prostaglandins) and leukotrienes (a related group of lipids) are derived by enzymatic synthesis from one of ... Prostaglandins in minute amounts produce a broad range of physiological effects in almost every system of the body. ... Most prostaglandins cause uterine contraction, and they are sometimes administered to initiate labour. ...
Human digestive system - Contractions, Motility, Digestion | Britannica
Human digestive system - Contractions, Motility, Digestion: The contractions of the circular and longitudinal muscles are regulated by electrical impulses that begin with the passage of calcium ions into the muscle cell. The duodenal pacemaker sends electrical impulses down the small intestine at a rate of 11 cycles per minute in the duodenum, gradually decreasing to 8 cycles per minute in the ileum. These electrical changes are propagated in the longitudinal muscle layer of the wall of the small intestine. Occurring simultaneously with the slow-wave electrical activity may be fast, spikelike electrical charges. This type of electrical activity originates in the circular muscle layer of the intestinal