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34 Cards in this Set
- Front
- Back
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Intestinal wall enzymes |
1. Break down di and olgiosaccharides 2. Peptides to smaller peptides and aa |
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Sucrose |
Broken down by sucrase Glucose and fructose |
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Maltose |
Broken down by maltase To glucose and glucose |
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Lactose |
Broken down by lactase To glucose and galactose |
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Celiac disease |
Gluten (protein in grains) damages villi -decreases absorption area for everything - increase bacterial fermentation in large intestine • gas and diarrhea |
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Absorption in small intestine due to |
Main site due to 1. Large surface area (folds, billi, microvilli) 2. Nutrients = smaller molecules |
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How things enter enterocytes |
1. Monosaccharides = 2° AT 2. Aa and di+tri peptides = 2° AT 3. Fats = diffusion 4. Water = osmosis
Exception : fructose = facilitated transport
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How nutrients leaves enterocytea |
1. Monosaccharides = facil. Trans (blood) 2. Aa & di+tri peptides = facil. Trans (blood) 3. Fats -long chains and MG=diffusion (lymph) - short chains = diffusion (blood) 4. Water = osmosis (blood & lymph) |
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MG and FA >12 carbon absorption |
1. Diffuse into enterocytes 2. Exocytosis from enterocyte 3. Diffuse into lymph lacteal Long chain, E.g. cholesterol, fat soluble vit. |
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How much water is absorbed at the small intestine |
8500ml/day |
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How muhc water ingested per day |
2000ml/day |
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H2O from secretions |
7000ml/day |
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When do nutrients in blood go? |
To liver via hepatic portal vein |
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Where do nutrients in lymph go |
From lacteals to thoracic duct To subclavian vein |
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Bile consists of |
1. water 3. Bile salts 2. Cholesterol 4. Bile pigments 5. Ions 6. Detoxifies/inactivated drugs, toxins, hormones |
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Emulsofication |
Break down of large globules of fat into many smaller droplets |
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Functions of bile salts |
1. Emulsification 2. Micelle formation |
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Micelle formation |
Keeps fats products in solution Micelle = bile salts & phospholipids - interior is hydrophobic - exterior is hydrophilic |
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Micelle |
NOT absorbed into the enterocyte Simply the "bus" (micelle) taking the "students" (fa&MG) to "school" (enterocyte) |
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Chylomicron |
Fat and protein package Water soluble |
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Gastric motility/secretion regulatory phases |
1. Cephalic phase 2. Gastric phase 3. Intestinal phase |
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Cephalic phase |
Prepares stomach for food Triggers: thoughts, sight, smell, taste of food |
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Cephalic phase causes |
Increase gastric secretion - increase enzymes - increase acid secretion Increase smooth muscle motility |
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Enteric NS |
GI tracts own nervous system |
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Gastric phase |
Activated by food in stomach (stretch receptros) Cause increase stomach activity (same as previous phase) |
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Other factors that incease gastric secretion |
Ca++ Alcohol Caffeine Aa Peptide |
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Food and pH in stomach |
Food acts as buffer As stomach empties pH lowers At < 3 pH enteric shut down stomach secretion |
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Intestinal phase |
Controls rate o chyme (food and gastric jucie) entry into duodenum |
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Stages or intestinal phase |
1. Increase gastric secretion into duodenal initially 2. Decrease gastric motility (slows emptying) 3. Decrease gastric secretion (acid, enzymes) |
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Why is gastric emptying regulated |
1. So acid has time to be neutralized in sm. Intestine 2. Tonicity doesnt overwhelm sm. Intestine 3. There is time for dig/abs in sm. Intestine |
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Entero____ |
Small intestine |
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What causes gastric motility to decrease |
1. CCK released 2. Enterogastic reflex |
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Enterogastic reflex |
Triggered by as/peptides, acid, duodenal stretch, hypertonicity Causes decrease gastric motility - directly - signal CNS - SNS |
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Why do gastric secretion decrease? |
1. Secretin (released due to acid) 2. CCK (released due to aa & fa) |
