Chapter 3 - 20:27 I. Four processes A. Motility: the...

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20:27 I. Four processes A. Motility : the process of moving food through the gut A.1. Peristalsis : movement, rhythmic contractions in gut. Without it, constipation A.2. Segmentation : mixing, random contractions in gut to break up food, mixes food with digestive secretions B. Secretion B.1. Secretions act to break down food, moisten and lubricate it to help it pass smoothly through gut B.2. Enzymes : proteins that act as catalysts, only certain molecules fit to create new produce C. Digestion : Breaking down large nutrient molecules so that the body can absorb them D. Absorption : movement of nutrients across cell membrane, into gut, into cells lining small intestine, into bloodstream II. Food’s path through the gut A. Mouth : first organ of digestion A.1. Function A.1.a. Mechanical breakdown of food (chew) A.1.b. The more you chew, the easier it is for intestines to digest food A.2. Secretion A.2.a. Saliva lubricates food A.3. Enzyme A.3.a. Amalyse from saliva acts on amylose (starch_ B. Esophagus B.1. Function
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B.1.a. Peristalsis: moves food B.1.b. Mucus lines it C. Stomach C.1. Function C.1.a. Churning: mix and grind (chyme) C.1.b. Absorption—slowly releases food C.1.c. Protein breakdown C.2. Secretion : C.2.a. Protease C.2.b. Hydrochloric acid C.2.b.1) Sterilizes food, doesn’t kill all bacteria though C.2.b.2) Denatures (changes) protein- breaks it down C.2.c. Protective mucus C.2.c.1) Protects stomach from acid and protease C.2.c.2) Without it, stomach would digest itself C.2.c.3) When mucus barrier fails, acid burns stomach lining —ulcer D. Lower esophagul sphincter D.1.a. Separates esophagus and stomach D.1.b. Stops acid stomach contests from flowing back into esophagus D.1.b.1) Gastric reflux: sphincter fails D.1.b.2) Heartburn: esophagus has no mucus barrier to protect itself
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E. Small Intestine E.1. Contains the duodenum, jejunum, and ileum, ten feel long E.2. Function E.2.a. Chemical breakdown of food E.2.b. Absorption E.2.b.1) What ? glucose, fat, AA, water soluble vitamins, some minerals, 80% of alcohol) E.2.b.2) into blood vessels (water soluble materials) and lymphatic system E.2.b.3) Villi E.2.b.3.a) Fingers lining surface of the small intestine E.2.b.3.b) Increase surface area of the small intestine E.2.b.3.c) Take nutrients, spread them out into film E.2.b.3.d) Single layer of mucosal cells which absorb nutrients E.2.b.4) Circulatory System E.2.b.4.a) Most nutrients are water soluble and are able to be absorbed into bloodstream E.2.b.4.b) Fat packaged in mucosal cells E.2.c. motility E.3. Secretions E.3.a. Bile E.3.a.1) Made in lover, stored in gall bladder E.3.a.2) Released only when needed E.3.a.3) Emulsifier: mixes water and fat
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E.3.b. Sodium bicarbonate E.3.b.1) From pancreas E.3.b.2) Neutralizes acid E.3.c. Amylase E.3.c.1) From pancreas E.3.c.2) Breaks down starch E.3.d. Protease E.3.d.1) From pancreas E.3.d.2) Breaks down protein E.3.e. Disaccharidase E.3.e.1) From intestine E.3.e.2) Break down disaccharides E.3.e.3)
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Chapter 3 - 20:27 I. Four processes A. Motility: the...

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