The+Stomach+to+Large+Intestine+MV

Molly Vaughn 5 September 2008 Human Biology

8.3 Stomach to Small Intestine Stomach: Muscular sac that mixes food with gastric juices to form chyme, which enters the small intestine. Rugae: Deep folds, as in the wall of the stomach. Gastric glands: Gland within the stomach wall that secretes gastric juice. Pepsin: Enzyme secreted by gastric glands that digests proteins to peptides. Small intestine: Long, tube like chamber of the digestive tract between the stomach and large intestine. Duodenum: First part of the small intestine where chyme enters from the stomach. Bile: Secretion of the liver that is temporarily stored and concentrated in the gallbladder before being released into the small intestine, where it emulsifies fat. Lipase: Fat-digesting enzyme secreted by the pancreas. Villus: Small, finger-like projection of the inner intestinal wall. Lacteal: Lymphatic vessel in an intestinal villus; it aids in the absorption of lipids. Lactose intolerance: Inability to digest lactose because of an enzyme deficiency.

(1) What are the functions of the stomach? - The stomach stores food, initiates the digestion of protein, and controls the movement of chyme into the small intestine. (2) What are the structures of the stomach that perform these functions and describe their role? - The stomach has three muscles layers and the mucosa has folds called rugae. Gastric glands present in the mucosa secrete mucus, HCl, and pepsin, an enzyme that digests protein. Micrograph of gastric pits. Peristalsis in the stomach controls the secretion of chyme into the small intestine at the pyloric sphincter. (3) What are the functions of the small intestine? The small intestine completes the digestion and absorbs nutrients. (4) What are the structures of the small intestine that perform these functions and describe their role? - The small intestine contains enzymes to digest all types of foods, primarily carbohydrates, proteins, and fats.

8.4 Three Accessory Organs and Regulation of Secretions Pancreas: Internal organ that produces digestive enzymes and the hormones insulin and glucagon. Pancreatic amylase: Enzyme in the pancreas that digests starch to maltose. Trypsin: Protein-digesting enzyme secreted by the pancreas. Lipase: Fat-digesting enzyme secreted by the pancreas. Hormone: Chemical signal produced by one set of cells that affects a different set of cells. Liver: Large, dark red internal organ that produces urea and bile, detoxifies the blood, stores glycogen, and produces the plasma proteins, among other functions. Bile: Secretion of the liver that is temporarily stored and concentrated in the gallbladder before being released into the small intestine, where it emulsifies fat. Bladder: A pear-shaped organ just below the liver.

(5) What are the three main accessory organs that assist with the digestive process? Describe how each contributes to the digestion of food. The pancreas, the liver, and the gallbladder are the three main accessory organs that assist with the digestive process. (6) How are digestive secretions regulated in the body? A hormone regulates digestive secretions in the body.

8.5 The Large Intestine and Defecation Large intestine: Last major portion of the digestive tract, extending from the small intestine to the anus and consisting of the cecum, the colon, the rectum, and the anal canal. Cecum: Small pouch that lies below the entrance of the small intestine and is the blind end of the large intestine. Vermiform appendix: Small, tubular appendage that extends outward from the cecum of the large intestine. Colon: The major portion of the large intestine, consisting of the ascending colon, the transverse colon, and the descending colon.

(7) What are the different parts of the large intestine? The large intestine includes the cecum, the colon, the rectum, and the anal canal. (8) What is the function of the large intestine? The large intestine absorbs water, which prevents dehydration, it absorbs vitamins produced by bacteria, and it forms feces.