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4 Cards in this Set
- Front
- Back
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Overview of the digestive system |
A. irregular tube called alimentary canal or gastrointestinal (GI) Tract and accessory organs of digestion
B. Food must first be digested and then absorbed |
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Primary mechanisms of the digestive system |
A. Ingestion- complex foods taken into the Gi tract
B. Digestion-group of processes that break complex nutrients into simpler ones 1. Mechanical digestion- breakup of large chunks of food into smaller bits 2. Chemical digestion- breaks large molecules into smaller ones
C. motility- a number of GI movements resulting from muscular contraction
D. Secretion- release of digestive juices and hormones that facilitate digestion
E. Absorption- movement of digested nutrients into the internal environment of the body
F. Regulation- neural, hormonal, and other mechanisms that regulate digestive activity |
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Wall of Digestive tract |
A. Digestive tract described as tube that extends from north to south.
B. Wall of the digestive tube is formed by four layers of tissue. 1. mucosa- type varies depending on GI location ( tough and stratified or delicate and simple epithelium); mucus production
2. Submucosa- connective tissue layer
3. Muscularis- circular, longitudinal, and oblique (in stomach) layers of muscle important to GI motility a. Peristalsis- "wavelike" movement pushes food down the tract b. segmentation- "back and forth" movement
4. Serosa- Serous membrane that covers the outside of abdominal organs; it attaches the digestive tract to the wall of the abominopelvic cavity by forming folds called mesenteries |
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absorption |
A. definition- process by which digested food moves from intestine into blood and lymph
B. Foods and most water, minerals, and vitamins are absorbed from small intestine; some water and vitamin K also absorbed from large intestine
C. Surface area absorption 1. Structural adaptations increase absorptive surface area 2. Fractal geometry- study of fragmented geometric irregular shapes such as those in lining of intestine |
