PHYS 1302 Lecture 7: ch-21-the-digestive-system-human-physiology-an-integrated-approach
Document Summary
Food enters the gi tract consisting of esophagus, stomach, small intestine, and large intestine. Portion of gi tract running from stomach to anus is known as the gut". Digestion: chemical and mechanical breakdown of food. Secretions are added to ingested food by secretory epithelial cells including the salivary glands, liver, gallbladder, and pancreas to create the soupy mixture known as chyme". First stages of digestion occur with chewing and salivary secretion in oral cavity by 3 pairs of salivary glands. Parotid glands near hinge of jaw. Swallowed food passes into esophagus (skeletal muscle that transitions into smooth muscle way down) Esophagus ends at stomach (holds 2l of food) Pylorus (gatekeeper between stomach and small intestine) has pyloric valve. Pyloric valve is a thickened band of smooth muscle. Most digestion and absorption occurs in small intestine. Secretions from pancreas and liver enter here. Sphincter of oddi keeps pancreatic fluid and bile from entering small intestine except during a meal.
