“I Am Smart” Quiz Where digestion first begins? What glands secrete hydrochloric acid? What is the length of the small intestine? The name of the projections on the villi? The name of small lymphatic vessels? What organ produces bile? What organ secretes bile? What is the name of the portion of large intestine that contains no villi?

What You Need to Know Mouth Where digestion begins Name of structure at back of the mouth? Esophagus Circular and longitudinal bands of muscle Peristalsis = rhythmic contractions esophageal sphincter

What You Need to Know Stomach Volume ranges from 50 ml to 6.0 L Parietal glands secrete HCl Mucos secreted from mucos neck cells Chief cells secrete pepsinogen Little absorption occurs except for alcohol Chyme is slushy, acidic mixture

What You Need to Know Small Intestine 90% of digestion occurs first two sections Duodenum, jejunum, ileum Villi = highly vascularized; contain small projections called microvilli; increase absorptive surface up to 600-fold Large surface area facilitates speed Villi contain lymphatics called lacteals Lacteals transport fatty materials (from the liver) to lymphatic system

What You Need to Know Small Intestine Segmentation contractions Peristalsis Bile, produced in the liver and stored and secreted by the gallbladder, helps to increase solubility and digestibility of lipid droplets by emulsifying them Pancreas secretes bicarbonates (alkali) to help buffer HCl from stomach that remains in the chyme

What You Need to Know Large Intestine Final pathway for digestion Absorption of water, electrolyes, storage of digestive residue (fecal matter) Terminal portion of GI tract contains no villi and is known as the colon Ascending, transverse, descending, sigmoid colon, rectum, and anal canal Bacterial fermintation produces gas (flatus)