Chapter 3 Notes Digestion

Chapter 3 Notes Digestion - Chapter 3 Notes Digestion...

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Chapter 3 Notes Digestion, Absorption, and Transport 1. Digestion is the process of breaking down foods into nutrients to prepare for absorption while overcoming 7 challenges (pg. 71). 2. Anatomy of the digestive tract the Gastrointestinal (GI) tract is the flexible muscular tube from the mouth to anus. The lumen is the inner space of the tract. a. The mouth is the beginning of the digestive system. Digestion in the mouth involves mastication (chewing), the stimulation of taste buds, and swallowing. The epiglottis closes to prevent food from entering the pharynx. After swallowing the food is called a bolus. b. The esophagus is the tube that leads to the bolus to the stomach. There is a sphincter at the upper and lower (also known as the cardiac sphincter) ends of the esophagus. 3. The stomach adds juices and grinds the bolus to a semiliquid mass called chyme. The pyloric sphincter regulates the flow of partially digested food into the small intestine. a. The small intestine receives digestive juices from the gallbladder and the pancreas. The three segments of the small intestine are the duodenum, the jejunum, and the ileum. b. The large intestine (colon) begins at the ileocecal valve and ends at the rectum and anus. The chyme passes by the opening of the appendix. 4. The Muscular Action of Digestion- under autonomic control a. Peristalsis pushes the digestive contents along. b. Stomach action involves circular, longitudinal, and diagonal muscles. (pg. 75). c. Segmentation is contractions by circular muscles that contract and squeeze contents to promote mixing with digestive juices. (Know the difference between peristalsis and segmentation).
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This note was uploaded on 09/09/2008 for the course F&N 303 taught by Professor Burgess during the Spring '08 term at Purdue.

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Chapter 3 Notes Digestion - Chapter 3 Notes Digestion...

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