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27 Cards in this Set
- Front
- Back
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Digestive system Function |
-Break down food to individual constituents -Absorbed nutrients into blood |
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Digestion Processes |
1.) Ingestion: taking in food 2.) Digestion: mechanical and Chemicle breakdown of Food -Secretion release enzymes to aid in digestion 3.) Absorbtion: taking in nutrients>blood 4.) Elimination |
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Components of Digestion |
1.) Mouth 2.) Esophagus 3.) Stomach 4.) Small intestine 5.) Accessory organs 6.) Large intestine |
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Mechanical Digestion |
-Chewing, Biting(Teeth) and mixing(tongue) |
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Chemical Digestion |
-Salivary glands: 3 exocrine glands produce saliva -Amylase: enzyme breaks down starch>simple sugar -Bicarbonate |
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GI tract anatomy |
-Lumen: inside of tract -Mucosa: inner lining of epithelium -Sub mucosa: middle layer of connective tissue, has blood and lymphatic vessels -Muscularis externa: outer layer of smooth muscle |
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Esophagus |
-Hollow Muscular tube behind trachea -Transport bolus from pharynx>stomach -Peristalsis: automatic rythmic contractions of muscularis externa -No digestion |
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Stomach |
Mechanical digestion: Muscularis externa churns contents>chyme (bolus>chyme) -Chemical Digestion: Gastric glands 1.) Parietal Cells 2.) Chief Cells 3. Enteroendocrine Cells |
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Parietal Cells |
-Secretes HCL HCL denatures food and kills microbes and Activates precursor pepsinogen |
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Chief Cells |
-Secretes Pepsinogen Pepsinogen combines with HCL to produce pepsin Pepsin: digest proteins |
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Enteroendocrine Cells |
-Secretes Gastrin Gastrin relaxes pyloric sphincter and stimulates production of stomach acids and enzymes |
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Small intestine |
-Completes digestion and majority of nutrient absorbtion -3 sections 1.) Duodenum (10 inches) 2.) Jejunum (8 feet) 3.) Ileum (12 feet) |
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Duodenum and Jejunum |
-Absorbs: Carb, lipids, amino acids, Calcium, and Iron. |
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Ileum |
-Absorbs: bile salts, vitamin b 12, H20, and electrolytes |
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2 major types of contraction |
1.) peristalsis 2.) Segmentation: coordinated muscle constriction in segment >mixes chyme -requires help from accessory organs |
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Accessory Organs |
1.) Liver: produces bile >acids in lipid digestion (emulsifies fat) 2.) Gall Bladder: stores and releases bile>into duodenum as chyme passes. 3.) Pancreas: produces pancreatic juice in response to gastrin and chyme in duodenum Pancreatic juice: -Pancreatic amylase: starch>glucose -Trypsin and Chymotypsin: proteins>AA -Nuclease: Nucleic acids>nucleotides -Lipases: Lipids>glycerol and fatty acid |
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Absorbption |
-Nutrients> blood capillaries -Lipids> lymphatic capillaries (lacteals) -requires large surface area (2200ft^2) |
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Surface Area |
-Length~ 21 ft (7m) -Time: 3-5 hrs -Structures: 1.) Circular folds: ridges of the mucous 2.) Villi: finger like projections on circular fold 3.) microvilli: small finger like projections on the cells making up the villi |
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Large Intestine: Function |
-Water, vitamins and electrolyte absorbtion -compaction of ingestible material -COntain several microbiota (bacteria) _prevents pathogenic bacteria from invading -Produce vitamins (B and K) |
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Large intestine: Sections |
1.) Cecum: Pouch at the beginning of large intestine 2.) Colon Segments -ascending -transverse -descending -sigmoid 3. Rectum |
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Basalmetabolic Rate |
-Minimum energy to maintain body functions -rate of energy when: awake resting lying down and 12 hours of fasting |
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Metabolic Conditions |
Regulated by: 1.) Endocrine System 2.) Autonomic nervous system 2 States: 1.) Absorptive metabolism 2.) Absorptive metabolism |
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Absorptive Metabolism |
-Energy input exceeds output (use) -Time: during 3-5 hours after consuming food(directly after consumption) -Results: energy being stored as macronutrients |
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Post-absorptive metabolism |
-Energy output (use) exceeds input -Time: 4-5 hours after consuming food, until next meal -Result: macro molecules broken down to > energy |
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Regulation of Blood Glucose Levels: 1.) Insulin: Actions |
Actions: -Promote uptake of glucose by cells -Increase anabolism (Glycogen synthesis, Triglyceride synthesis, and Protein synthesis) -Decrease Catabolism -Secretion |
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Regulation of blood glucose levels: 1.) Insulin: Secretion |
Secretion: -Produces by: beta cells of the pancreas -Increased during Absorptive states -Decreased during Post-absorptive states -Stimulated by: 1.) Increase in plasma glucose 2.) Parasympathetic nervous system 3.) Glucose dependent insulinotropic peptide Produced by: small intestine -Function: enhances release of insulin after intake of food |
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Regulation of blood glucose levels: 2.) Glucagon:Actions |
-Increases catabolism Glycogenolysis lipolysis protein breakdown -decrease anabolism Glucose sparing for nervous system other cells receive other energy sources |
