Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
54 Cards in this Set
- Front
- Back
|
Small intestine |
6 meters (21 feet) Longest compartment of canal Most enzymatic hydrolysis of food macromolecules and most of the absorption of nutrients into the blood occur in the sm. Intestine |
|
|
3 parts of sm. Intestine |
Duodenum Jejunem: middle section Ileum: contains peyers patch (immune response), leads to lrg intestine |
|
|
Duodenum |
First 25 cm of sm. I. Chyme from the stomach mixes digestive juices from pancreas liver gallbladder and small intestine |
|
|
Pancreatic Juice from pancreas in duodenum |
Enzyme for digestion: carbs (amylase), proteins (protease trypsin and chymotrypsin), DNA and RNA and fates (lipase) An alkaline solution (bicarbonate) neutralizes pH of chyme |
|
|
Duodenum receives bile from liver |
Bike emulsified fat Acts as detergent |
|
|
Pancreatic secretions |
Produces trypsin and chymotrypsin Activated in lumen of duodenum |
|
|
Trypsin |
Cleaves peptide chains mainly at carboxyl side of amino acids lysine and arginine Produced by protease in pancreas |
|
|
Chymotrypsin |
Cleaves peptide amide bonds at carboxyl site Lrg hydrophobic amino acid Hydirlysizes other amide bonds |
|
|
Change in pH in pancreas |
pH gradually increases in small intestine from 6 to 7.4 in ileum pH drops to 5.7 in the caecum but then gradually increases again reaching 6.7 in the rectum
|
|
|
Bike production in liver |
In sm. Intestine, bile aids in digestion and absorption of fats. Bile emulsifies fat globules to microscopic droplets Bile is made in liver and stored in gallbladder Bile contains by-products of red blood cells destroyed by liver. These are eliminated in feces |
|
|
Chart |
Back (Definition) |
|
|
Secretions of sm. Intestines |
Epithelial lining of the duodenum produces several enzymes Some are secreted into lumen while others are bound to surface |
|
|
Enzymes from intestinal epithelium |
A |
|
|
More charts |
A |
|
|
Absorption |
Nutrients in the lumen must pass the lining of digestive tract Most digestion occurs in duodenum but absorption of nutrients and water mostly occurs in the jejunum and ileum Enormous surface area of sm. Intestine (300m2) is an adaptation that greatly increases rate of nutrients of absorption |
|
|
Surface area and large circular folds |
Villi: finger like projections Microvilli: microscopic extensions on surface of columnar epithelial cells of villi (brush border) |
|
|
Transport of nutrients |
Passive: lipids by diffusion, fructose (a simple sugar) moves by facilitated diffusion down its concentration gradient, water by diffusion/osmosis from lumen of the intestine into the epithelial cells and then into capillaries Active: amino acids, small peptides, vitamins, and most glucose molecules plus Na through a cotransporter protein are pumped against concentration gradients by the epithelial cells of the villus (active=greater absorption) |
|
|
Hepatatic portal vein |
Carries nutrient-rich blood from capillaries of the villi to the liver, then to the heart |
|
|
Liver |
Regulates nutrient distribution interconverts many organic molecules detoxifies many organic molecules Liver helps regulate the levels of glucose in the blood, blood exiting the liver has a glucose concentration very close to 90mg per 100 mL regardless of carb content of the meal From the liver, blood travels to the heart, pumps blood and nutrients to all body |
|
|
Fat absorption |
Epithelial cells absorb fatty acids and monoglycerides, turn the to triglycerides Fats coated with phospholipids, cholesterol, and proteins to form chylomicrons |
|
|
Chylomicrons |
Water soluble Transported into a lacteal (lymphatic vessel in villus) Deliver chylomicron-containing lymph to lrg veins that return blood to heart |
|
|
Fat absorption |
A |
|
|
Submucosa blood capillaries |
Nutrient absorption Carries sugar and amino acids |
|
|
Lacteals |
Lymph capillaries Part of lymphatic system Carries glycerol and fatty acids Lymph is deposited in one or two large ducts in the chest region (right lymphatic duct and thoracic duct) Lymph then travels from these ducts into venous circulation via subclavian and jugular veins |
|
|
Enteric division of the nervous system |
Regulates the digestive process as needed A division of the autonomic nervous system that controls gastrointestinal motility and secretions Functions independently of the brain and spinal cord |
|
|
Endocrine system regulates digestion |
Releases and transports hormones Hormones released by stomach and duodenum control digestive secretions into alimentary canal |
|
|
Hormone |
Substance secreted by cell, transported via circulatory system, affects a different set of target cells Gastrin, Gastric inhibitory peptide (GIP), secretin, cholecystokinin (CCK) |
|
|
Gastrin |
Produced by stomach after protein-rich meal Food stretches stomach wall and gastrin is released into bloodstream, returns to stomach, and stimulates gastric juices |
|
|
Gastric inhibitory peptide (GIP) |
Produced by duodenum wall Inhibits gastric gland secretion |
|
|
Secretin |
Produced by duodenum wall Release is stimulated by entrance of chyme Regulates pH in duodenum by: -inhibiting gastric acid secretion by the parietal cells -stimulating bicarbonate production in pancreas |
|
|
Chlocystiokinin (CCK) |
Produced by duodenum wall Release stimulated by proteins and fat in chyme Stimulated release of pancreatic digestive enzymes which stimulates bile in liver and release it from gallbladder Inhibits gastric juices |
|
|
Regulation of energy storage |
Body stored energy-rich molecules not needed for metabolism First stored in liver and muscle cells in polymer as glycogen Excess energy after that is stored in fat If calories drop, expends liver glycogen, then muscle glycogen, and fat |
|
|
Glucose homeostasis |
Glucose: fuel for cellular respiration and source for carbon skeleton biosynthesis Homeostasis is maintained by insulin and glucagon (regulate synthesis/breakdown of glycogen) Site is at liver |
|
|
Liver and glucose homeostasis |
Carb-rich meal raises insulin levels Excess glucose in liver (portal vein) stored as glycogen Btw meals, low blood sugar causes glucagon to stim liver to break down glycogen and release glucose intonblood |
|
|
Cell organization in pancreas |
Glucagon and insulin are produced in islets of pancreas Alpha cells make glucagon Beta cells make insulin |
|
|
Blood glucose feedback |
A |
|
|
Importance of insulin |
Insulin acts on nearly all body cells to stimulate glucose uptake from blood Brain cells are an exception, they can take up glucose whether or not insulin is present |
|
|
Diabetes mellitus |
Caused by deficiency of insulin or a decreased response to insulin in target tissues Cells can’t take up enough glucose so level of glucose in bloodstream may exceed the capacity of kidney absorption Sugar in urine is a test for diabetes |
|
|
Type I diabetes |
Autoimmune disorder Immune system destroys beta cells of the pancreas Usually appears during childhood |
|
|
Type 2 diabetes |
Failure of target cells to respond normally to insulin Excess body weight and lack of exercise increase risk Generally appears after age 40 but can develop earlier in sedentary people |
|
|
Endocrine function of Pancreas (spongy organ behind stomach) |
Secrete directly in bloodstream Regulates blood glucose: Insulin: released in response to increase level of blood glucose Glucagon: released in response to decrease level of blood glucose |
|
|
Exocrine function of pancreas |
Pancreatic juice secretes directly into ducts in duodenum Sodium bicarbonate: neutralizes stomach acids Pancreatic amylase: starch digestion Trypsin and chymotrypsin: protein digestion Lipase: fat digestion |
|
|
Regulation of appetite and consumption |
Researchers discovered mechanism that regulates body weight Obesity contributes to colon and breast cancer, heart attacks, stroke, and diabetes |
|
|
Short term regulation of appetite |
Hormones impact center of brain “satiety center” Ghrelin: secreted by stomach wall to trigger hunger feeling before meals Insulin and Peptide tyrosine tyrosine (PYY): released, by ileum and colon in response to feeding, suppresses appetite |
|
|
Long term regulation of appetite |
Leptin: produced by fat, suppresses appetite and plays role in regulating body fat levels |
|
|
Chart of hormones |
A |
|
|
Chart 2 |
A |
|
|
Dental adaptations |
Dentition: animals assortment of teeth reflect diet Nonmammalion have less specialized teeth |
|
|
Stomach and intestinal adaptations |
Carnivores have large expandable stomach Herbivores and omnivores have longer alimentary canals (longer time needed to digest vegetation due to not having enzymes to break down plants) |
|
|
Mutualistic adaptations |
Bacteria coexist Some produce vitamins Regulate development of intestinal epithelium and function of innate immune system |
|
|
Microbiome |
Collection of microorganisms living on the body Use DNA sequencing approach to study Different association with age, disease, dirt |
|
|
H. Pylori |
Disrupt stomach health by eliminating other bacterial species from the stomach |
|
|
Herbivores mutulistic adaptations |
Fermentation chambers where organism live to digest cellulose Rabbits and rodents pass food through their canal twice Ruminants: 4 chambers (in cow) ie: cow eats grass, goes to rumin, then reticulum, then regurgitate into cud, then go back into omasum to draw out water, then abomasum |
|
|
Giant tubeworms |
No digestive tract Bacteria in them releases nutrients: CO2, O2, nitrogen and hydrogen sulfide |
