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64 Cards in this Set
- Front
- Back
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What are the valves of the GI tract? |
The epiglottis, esophageal sphincter, pyloric sphincter, ileocecal valve, and the anus.
Valves control the flow of contents and are normally one way. |
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What are the stages of digestion? |
1) Mechanical Digestion (chewing, some in stomach) 2) Chemical Digestion (minimally in chewing, stomach and upper SI) 3) Absorption of nutrients (Lower SI) 4) Reabsorption (LI, water and electrolytes) |
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What is the function of these valves: epiglottis, esophageal sphincter, pyloric sphincter, ileocecal sphincter, and the anus |
Epiglottis: prevents food/drink from entering lungs via trachea Esophageal sphincter: prevents acidic stomach contents from going back up esophagus Pyloric: controls rate of digestion Ileocecal: separate SI and LI Anus: voluntary poo! |
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What are the secretory glands of the GI tract and where are they? |
Salivary gland (in the mouth), gastric gland (in the stomach), intestinal gland (SI), pancreas, and liver |
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What does the salivary gland secrete and what do these secretions do? |
Saliva: overall, moistens and lubricates food. Mild antibacterial properties. Salivary amylase: small breakdown of starches. Polysaccharides to smaller polysaccharides, and even disaccharides. Salivary lipase: not very active in adults. More for babies. Break down milk fat. |
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What does the gastric gland secrete and what do these secretions do? |
Overall, provides fluid, HCl, and enzymes for protein digestion. Pepsin is secreted as pepsinogen and activated by HCl. It breaks proteins into polypeptides/tripeptides/dipeptides. |
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What does the intestinal gland secrete and what do these secretions do? |
MANY enzymes for 90% of starch/protein digestion. Lactase, maltase, sucrase, tripeptidase, dipeptidase. |
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What does the pancreas secrete and what do these secretions do? |
Enzymes for starch, fat, and protein digestion. Pancreatic amylase (starch), lipase (fat), and bicarbonate ion (an antacid to neutralize acidic stomach contents in duodenum). |
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What does the liver secrete and what do these secretions do? |
Bile to emulsify fat. Bile is stored in the gall bladder. |
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What type of muscle is the majority of GI tract muscle? What are the two types of muscles? What type of motion can they produce and what for? |
Smooth - no conscious control, except anus. Circular and longitudinal (diagonal in stomach too) muscle helps produce peristalsis, which pushes food through the GI. |
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What encourages peristalsis? |
Fiber, fluid intake, and caffeine. |
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What feature of the small intestine allows for efficient absorption? |
Each villus (small intestine cell) is a fold, and they all have microvilli (even smaller little folds). High surface area. |
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How are nutrients circulated around the body from the digestive system? |
Capillaries surrounding SI pick up nutrients, go into portal vein to liver, processed, then to hepatic vein to heart. Or, lymph picks up molecules too big to fit into capillaries and dumps them into bloodstream to heart. |
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What is heart burn? How do you avoid it? |
Heart burn is acid reflux; stomach acid splashes up into esophagus. Causes are too much alcohol (relaxes esophageal sphincter), overeating, high fat delaying stomach emptying, spicy food, raw onion, posture (being horizontal). |
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What is constipation? How do you avoid it? |
Pain associated with bowel movement. You can have wide variations in timing so it's okay if you don't poo for 3 days. To avoid, adequate fluid, adequate fiber (retains fluid), regular physical activity, regular meals/sleeping. And go when you need to poo! |
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What is diverticulosis? |
Associated with and caused by low fiber diets. Weakening of digestive tissue walls, get pushed out by poo, and form pockets (diverticula). If little undigestible food bits get stuck and bacteria eat, leads to infection, then inflammation, then diverticulitis!! |
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What do lipids do in the body? |
Mostly energy storage. Sterols act as precursors to sex hormones, vitamin D, and bile. Phospholipids are part of cell walls. Padding for vital organs. Plus it tastes good and provides fat-soluble vitamins, ADEK. |
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What is a triglyceride made of? |
1 Glycerol + 3 Fatty Acids |
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What is a monounsaturated fatty acid? What is a polyunsaturated fatty acid? What are the two essential fatty acids? |
1 double carbon-carbon bond. More than 1 double carbon-carbon bond. Alpha-linolenic acid (omega-3) and linoleic acid (omega-6). |
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Give examples of sources of polyunsaturated, saturated, and monounsaturated fats. |
Polyunsaturated fats mostly come from plant-based fats, e.g., safflower and soybean oil. Saturated fats mostly come from animal-based fats except for tropical oils, such as coconut/palm kernel. Monounsaturated fats come from primarily olive oil, then canola oil. Solid @ room temp fats are likely to be saturated. |
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Where does cholesterol come from? What are sources of fat from grains, vegetables, fruits, dairy, and protein? |
Animal-based fats ONLY. E.g., liver. Grains: Crackers, pasta dishes with added fat Veggies: French fries Fruits: Fruit pies, avocado Dairy: whole milk, cheese, ice cream Protein: meat fat, skin, nuts |
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What is a good source of linoleic acid/omega 6 fatty acids? What is a good source of alpha-linolenic/omega-3 fatty acids? |
Omega-6 can be found in sunflower, corn, soybean, safflower, and cottenseed oil. Omega-3 can be found in flaxseed oil, but also canola, walnut, wheat germ, soybeans, butternuts, walnuts, salmon/tuna/lake trout/sardines, and dark leafy vegetables (spinach, kale, chard, etc.). |
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What does hydrogenation do to a polyunsaturated fatty acid? |
Break carbon/carbon double bonds and add hydrogens, making it saturated. Creates trans-fats unintentionally. It is treated similarly to a saturated fat in the liver despite being technically unsaturated. Natural unsaturated fats have a cis-configuration (more bendy). |
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Why hydrogenate? |
Longer shelf-life by decreasing oxidation (makes fat rancid). Cheaper because you can use polyunsaturated corn oil into saturated (hydrogenated vegetable oil). |
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What are some bad effects of hydrogenated vegetable oils? |
Creates saturated or trans-fats, which are strongly linked to atherosclerosis. Raises blood cholesterol.
Stanol Esters (Benecol) are the only kind that can REDUCE blood cholesterol. Trans fats MUST occur on food labels unless <0.5 g, in which case you can claim 0. |
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How much omega-6 and omega-3 do you need? |
Men and women need 1.6 grams and 1.1 grams of omega-3 per day, and 5-10x more of omega-6 (so up to 16 and 11 grams). |
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What are health benefits of the essential fatty acids? |
Omega-3 fatty acids are used to make eicosanoids, which can decrease blood pressure, increase vasodilation, reduce inflammation (helps with heart disease, diabetes, cancer, arthritis). Decreased heart disease risk! |
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Describe triglyceride digestion in the small intestine. |
Bile squirted into duodenum to emulsify fat. Breaks fat into droplets so lipase can access it. Short-chain fatty acids and glycerol can immediately go into the blood and straight to liver. Otherwise, need to be escorted via chylomicrons and become LDLs and HDLs. |
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Describe absorption of lipids in the GI tract and the assembly of LDLs/HDLs. |
Large lipids merge into micelles, move into intestinal cells, then incorporated into chylomicrons (balls of protein that get covered with triglycerides). Enter lymph and then blood, travel to liver. Assembled into LDLs and HDLs in liver. |
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What is the difference between LDLs and HDLs? |
Low density lipoproteins (BAD): more saturated fat and trans fat, mostly cholesterol. Increases heart disease risk because cholesterols can get dropped (oops) in blood stream, leading to plaques. SUPPOSED to go to cell for membrane use or synthesis of steroid hormones. High density lipoproteins: more protein, denser. |
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What causes high LDLs? How to improve your HDLs? |
A diet high in saturated fats and cholesterol (animal fat). Alcohol, smoking, and sweets contributes. Increase exercise and have a proper diet for HDL formation--there is no ONE food to eat for HDL formation. |
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How does atherosclerosis develop? |
Fatty plaque deposition from LDLs (cholesterol hardened with calcium deposits). Inflexible, so don't expand with heart beats and increase blood pressure. Reduce flow to kidneys. Also may trigger blood platelet clumping, so blood clots. |
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Risk factors for cardiovascular disease? |
Family history/genetics, gender (men or menopausal women), high blood cholesterol, hypertension, smoking, obesity/gut fat, pre-diabetes/diabetes, sedentary, high stress. |
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Negative and positive effects of fat on health? |
Negative: obesity, increased risk of type 2 diabetes. High saturated/trans fats increases LDL/blood cholesterol. Increased risk of heart disease/cancer. Positive: Flavor and vitamins ADEK. Monounsaturated fats and omega-3 fats decrease risk of heart disease. |
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What is the RDI for fat? |
20-35% of total kcals should be fat. Less than 10% should be saturated fat. NO trans fat. 6-10% should be linoleic (omega-6), and 0.6-1.2% should be linolenic (omega-3). Less than 300 mg of cholesterol per day. Fat is 9 kcal/g. |
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How to limit fat intake? |
Limit meat intake except for fish. Don't fry foods--bake, braise, broil, steam, poach, saute. Use herbs/spices. Trim fat after cooking. Replace fat sources like sour cream with Greek yogurt. |
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What is the difference between an essential amino acid and non-essential amino acid? |
Essential/indispensable amino acids cannot be made in the body, or not enough of it. 9 of them (Pvt. Tim Hill).
Non-essential/dispensible amino acids can be synthesized in your body as long as you have enough nitrogen. |
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What is the common amino acid structure? |
An amine group (nitrogen, unique to proteins) connected to a carbon, connected to a carboxyl group. Carbon has a hydrogen on one side and a variable side group. Change the side group, change the amino acid. |
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How is the sequence for amino acids determined? Why is the sequence so important? |
From DNA; over 100,000 proteins made by body. Sequence determines shape and function of protein. E.g., cystine contains sulfur, forming disulfide bonds with other cystines. 99% of the time you CANNOT get away with substitutions, e.g., sickle cell anemia. Glutamic acid replaced with valine. |
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What are functions of protein in the body? |
Everything! Muscles, growth, maintenance and repair (GI tract cells, skin), enzymes, transport proteins, blood clotting, immune function, fluid balance (albumin in the blood), energy source. 4 kcal/g!!! |
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How is protein digested in the body? |
Other than mechanical chewing, the stomach secretes HCl and pepsinogen, transforming it into pepsin. Cleaves proteins into smaller polypeptides, maybe some free amino acids.
Finished in small intestine, absorbed into blood. |
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How are the amino acids used in the body? |
Essential amino acids and nitrogen from non-essential amino acids delivered to cells for protein synthesis. Can repurpose to make other compounds. Gluconeogenesis. |
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What if you don't have enough of an essential amino acid? What if you have too many amino acids? |
Need to disassemble other proteins that have it, like your muscles.
Deaminate (cut off NH2). Makes ammonia (NH3), then neutralized with CO2 in urea cycle in liver. Excreted by kidneys. Strains the liver/kidneys. |
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Where can you get protein from? |
Animals: Meat, milk products, eggs. Plants: Legumes, soy, cereals/grains, veggies, nuts and seeds. Almost NONE in fruits!!!! |
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What determines protein quality? |
High quality: all 9 essential amino acids, easily digested (as in less waste, like breast milk vs. cow milk in a diaper).
Highest quality protein for humans is bovine colostrum (rare), casein (milk), egg (albumin) and whey. Soy and beef ALMOST there. |
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How do you get a complete protein? Examples? |
Must contain all 9 essential amino acids. Animal protein or SOY PROTEIN. Simply need to eat more soy since it is less digestible.
LEGUMES !!!AND!!! GRAINS. Important for vegetarians! Peanut butter sandwich. Rice and beans. Hummus and bread. Bean burrito. |
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What is the RDA for protein? |
0.8 g protein/kg body weight for 19 years+ (0.9 for under 19), or 1.2-1.7 g protein/kg body weight for athletes.
10-35% of total kcals. |
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What are health effects of a deficiency of protein or an excess? |
Deficiency (rare): stunted growth in children, immune system compromise in adults, hair loss, dull skin etc. Excess: increased calcium loss in urine so osteoporosis (except with soy), stressed kidneys/liver, bad for diabetics who already have stressed kidneys! Red/processed meats and colon cancer! |
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What are health benefits of a vegetarian diet? What about economical, ecological, and moral benefits? |
Lower risk of chronic diseases, low rates of heart/artery disease. Less saturated fats and LDLs. Lower hypertension/blood pressure. Defense against colon/rectal cancer. Cataracts, diabetes, diverticulosis, gallstones, osteoporosis. Animal welfare. Expensive to produce and ship meat. Healthier body weight. |
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What is a catabolic reaction? What is an anabolic reaction? When the body converts ATP to ADP for energy, which type of reaction is this? |
Catabolic: breaking down, releasing energy. Anabolic: building, using energy! Using ATP breaks off a phosphate, so it is a catabolic reaction, releasing energy for the cell to use. |
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Anaerobic metabolism vs. aerobic metabolism |
Anaerobic: not oxygen dependent. High respiratory rate/heart rate (<85% HR). Out of breath, muscles burn--can only manage one word at a time. short burst. Aerobic: oxygen dependent, used at REST and up to 85% max HR. |
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What is the ATP-PC system? |
Breaking bonds in ATP and phosphocreatine (helps regen ATP).
Anaerobic! |
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What is anaerobic glycolysis? |
Use muscle glycogen as fuel, breaking glycogen into glucose, then pyruvate (3 carbon), then lactic acid (3 carbon). Used by cells that ONLY use glucose (e.g., RBC's). Cori Cycle converts lactic acid back into glucose, then glycogen. |
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What is Aerobic Metabolism, also known as oxidative phosphorylation? |
Can use muscle/liver glycogen, blood glucose, muscle triglycerides, blood's free fatty acids/triglycerides, fat cell triglycerides, protein. Maximum ATP production via Krebs Cycle and ETC. About 60% of energy from fat metabolism at rest; increase activity, use more carbs, less fat. |
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Describe production of ATP from glucose in aerobic metabolism. |
Glucose (6C) to 2 Pyruvate (3C) (reversible). To acetyl-CoA (2C); CoA comes from B-vitamin family. Not reversible. Goes thru TCA cycle (add oxaloacetate, 4C, creating citrate, 6C). This removes hydrogens and puts onto FAD/NAD B-vitamin coenzymes. Then ETC forms ATP and water with oxygen. |
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What is the basal metabolic rate (BMR)? What is it affected by? |
Resting energy expenditure, affected by age, growth, sex, body composition, body weight, fasting, fever, thyroid hormone. More for sedentary people, less for athletes. |
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What happens to excess proteins, carbohydrates, and fat during feasting? |
Protein: after being used for body protein and for energy (deamination), turned into body fat (deamination). Carb: after used for energy needs (RBC's, brain, CNS) glucose to glycogen in liver/skeletal muscle or body fat. Fat: Glycerol to pyruvate or fatty acids to acetyl-COA for energy needs; otherwise, stored. |
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Where does your body get energy during fasting (only water)? |
Brain cells/CNS/RBC's take priority. Glycogen (up to 2000 kcal stored) into glucose. Runs out after a few days. Body fat (80 to 100,000 kcal stored) split into glycerol to glucose, ketogenesis. Once very desperate, use skeletal muscle; amino acids get deaminated for gluconeogenesis or pyruvate/acetyl-CoA for ATP. |
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What is ketogenesis? |
Fatty acid fragments (2C) become acetoacetate (4C) and acetone (3C). Helps prevent skeletal muscle catabolism. Side effects: Reduce BMR and decrease perception of hunger. (Can occur with low carb diet). You can undergo ketogenesis and use glycogen at same time. |
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Alcohol absorption and metabolism process |
20% of ethanol absorbed thru stomach when empty; full stomach delays absorption. Stomach also has alcohol dehydrogenase.
Most delivered to liver where greater amounts of alcohol dehydrogenase can metabolize at about 0.5-1 oz of ethanol per hour (1-2 drinks). |
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How much is one drink, or about 0.48 oz alcohol?
How many calories are in a gram of pure alcohol? |
A 12 oz 4% alcohol beer, a 4 oz 12% alcohol wine, 1.25 oz of 40% alcohol or 80 proof spirit (a shot).
7 kcal/g of alcohol. |
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Differences between men and women in ethanol breakdown, genetics.
What does the MEOS system in the liver do? |
Men make more alcohol dehydrogenase. Native Americans and Asians tend to make less.
MEOS is microsomal ethanol oxidizing system. MEOS prioritizes ethanol, giving drugs time to go into circulation and affect brain. Increase chance of OD. |
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Negative effects of ethanol on liver?
What is binge drinking? |
Fatty liver. Alcohol metabolite (acetaldehyde) damages liver, decreasing ability to make proteins, gluconeogenesis, and ability to process ammonia.
Acetaldehyde gives you hangovers. Effects come over time, not from binging (5 drinks for a man, 4 drinks for a woman). |
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Negative effects of alcohol on kidneys, brain, etc.? |
Kidneys: impaired function, build uric acid in joints (gout). Brain: cell death.
Acetaldehyde damages muscle tissue. High blood pressure, cancers: oral, esophageal, stomach, breast.
Gynecomastia in men. |
