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45 Cards in this Set
- Front
- Back
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Functions of Digestive System
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1. Process Food
2. Extract Nutrients from it 3. Eliminates residue 4. Ingestion 5. Digestion 6. Absorption |
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What does the digestive system produce?
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Enzymes and hormones
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Order of passage of food
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1. Mouth
2. Oral cavity 3. Pharynx 4. Esophagus 5. Stomach 6. Small intestine 7. Large intestine 8. Anal canal |
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What are the accessory organs?
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1. Teeth
2. Salivary glands 3. Liver 4. Gall bladder 5. Pancreas |
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Layers of the digestive tract
Inside-Outiside |
Mucosa
Submucosa Muscularis externa Serosa |
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Mucosa
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Inside layer
1. Epithelial cells- villi 2. Lamina propria- loose connective tissue layer 3. Muscularis mucosa- thin layer of smooth muscle |
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Submucosa
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Loose connective tissue
Contains blood vessels, nerves and lymphatic vessels Glands that secrete mucous |
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Muscularis externa
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Inner layer has circular muscles
Stomach has middle layer- oblique Outer layer- longitudinal muscles Function: move food thru the intestine; has pacemaker cells that set the rhythm of contractions. |
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Serosa adventitia
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membrane that lines a body cavity
dense fibrous connective tissue with widely spaced fibers |
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Digestive tract
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Oral cavity
Pharynx Esophagus Stomach Small intestine Large Intestine Rectum Anus |
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Oral cavity
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Mastication- breakdown food
Tongue- skeletal muscle Teeth- breakdown of food Salivary glands- moisten food |
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Intrinsic Salivary glands
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Indefinite number
scattered throughout oral tissue Moisten mouth and inhibit bacterial growth |
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Extrinsic salivary glands
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communicate with oral cavity via ducts, large discrete organs outside of oral cavity
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Parotid gland
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near earlobe (mumps is an inflammation and swelling of this gland, due to a virus)
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Submandibular gland
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Halfway along the body of the mandible
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Sublingual gland
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Floor of mouth
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Pharynx
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Deglutition- swallowing
Pharyngeal constrictors- force food downward during swallowing |
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Esophagus
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Connects pharynx to stomach
Begins at Cricoid cartilage Lower esophogeal sphincter keeps food moving in correct direction Prevents backflow into esophagus Secrete mucus for lubrication When empty, has deep ridges which allow for expansion |
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Heartburn
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when stomach acids enter esophagus
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Stomach
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Breaks food, liquifies food and begins chemmical digestion of proteins and some fat
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Rugae
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large folds of stomach mucosa
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Epithelium cells
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Parietal cells: secrete HCL and intrinsic factor
Chief cells: most numerous, secrete pepsinogin |
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Pepsinogen
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an inactive protein that is activated by the HCL of the stomach
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Pepsin
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(active form) digests dietary proteins to smaller peptide chains
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Goblet cells
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secrete mucous
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Regenerative (stem) cells
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divide rapidly for continuous supply of new cells to replace cells that die
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Mucous cells
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secrete mucous
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Enteroendicrine cells
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secrete hormones and panacrine messengers taht regulate digestion, eight kinds each producing its own messenger
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Chyme
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bolus of food material that moves to small intestine
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Regions of Stomach
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Cardiac orifice
Cardiac region Fundus region Body region Pyloric region |
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Cardiac orifice
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opening from esophagus
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Cardiac region
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area immediately inside the cardiac orific
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Fundus region
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Left of the cardiac, in direction contact with diaphragm, dome shaped portion
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Body region
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main portion forming greater and lesser curvatures
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Pyloric region
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funnel shaped terminal portion
pylorus opening to small intestine "guarded" by pyloric sphincter |
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Small intestine function
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Chemical digestion and nutrient absorption from chyme
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Small intestine parts
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1.duodenum- first 10 in., ends at duodenojejunal flexure (sharp curve) receives stomach contents, bile and pancreatic juice
2. Jejunum- next 8 ft, upper left of intestinal coils 3. Ileum- last 12 feet. lower right of intestinal coils |
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Modifications to increase surface area
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1. Plicae circularis: circular folds; mucosa and submucosa layers only; start in the duodenum and continue thorugh the middle of the ileum; cause chyme to flow in a spiral path
2. Villi: fingerlike projection (.5-1.5 mm) largest in the duodenum; epithelial cells consist of absorptive cells and goblet cells. 3. Microvilli: brushborder- projection of apical and cells |
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Large Intestine Function
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Receives about 500 mL of indigestible food a day and reduces it to 150 mL of feces by absorbing water and salts; eliminates feces by defecation
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Iliocecal valve
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at junction of small/large intestines; one-way passage
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Cecum
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sac extending inferiorly from iliocecal junction
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Appendix
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Fingerlike projection off of cecum; it is densely populated with lymphocytes and is a significant source of immune cells- thought to function as part of immune system
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Parts of large intestine
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Ascending colon: right side
Transverse colon: passes from right to left; inferior stomach and spleen Descending colon- left side Sigmoid colon- S-shaped near rectum |
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Rectum
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straight part of the large intestin; has three valves taht allow for retaining feces but passing gas
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Anus
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where feces leave body
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