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SMALL INTESTINE (FIGURE 15-9) Size—about 7 meters (20 feet) long but only 2 cm or so in diameter Divisions Duodenum Jejunum Ileum

SMALL INTESTINE Wall—contains smooth muscle fibers that contract to produce peristalsis Lining—mucous membrane; many microscopic glands (intestinal glands) secrete intestinal juice; villi (microscopic finger-shaped projections from surface of mucosa into intestinal cavity) contain blood and lymph capillaries

LIVER AND GALLBLADDER Size and location—liver is largest gland; fills upper right section of abdominal cavity and extends over into left side Liver secretes bile Ducts (Figure 15-10) Hepatic—drains bile from liver Cystic—duct by which bile enters and leaves gallbladder Common bile—formed by union of hepatic and cystic ducts; drains bile from hepatic or cystic ducts into duodenum Gallbladder Location—undersurface of the liver Function—concentrates and stores bile produced in the liver

PANCREAS Exocrine gland that lies behind stomach Functions Pancreatic cells secrete pancreatic juice (most important digestive juice) into pancreatic ducts; main duct empties into duodenum Pancreatic islets (of Langerhans)—cells not connected with pancreatic ducts; secrete hormones glucagon and insulin into the blood

LARGE INTESTINE (FIGURE 15-12) Divisions Cecum Colon—ascending, transverse, descending, and sigmoid Rectum Food enters through ileocecal valve; external opening called anus Wall—contains smooth muscle fibers that contract to produce churning, peristalsis, and defecation Lining—mucous membrane