Prelim 2 Review Part 1 - Lecture notes 11 PDF

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Prelim 2 Review Part 1 - Lecture notes 11...

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Prelim 2 Review 11/5/14 ~ Flow chart of fibrin - Arachidonic Acid  preprothrombin  prothrombin  thrombin  (is used by fibrinogen) fibrinogen  fibrin - Fibrin is used for blood clotting - Vitamin K deficiencies cause excessive bleeding - Bacteria in the colon produce vitamin K - Aspirin blocks cox 2 so it blocks conversion of arachidonic acid to preprothrombin - Decreases clotting - Anticoagulant ~ Gastric Surgeries - Gastric stapling: reduce the volume of the stomach - Problem: can still eat high caloric concentration of foods and staples can come out and cause infection (peritonitis) - Gastric balloon: expand stomach but only temporary solution - Gastric band: adjustable gastric band – feeling of being full so can only eat less amounts - Vertical banded gastroplasty (Reduce volume of stomach to increase firing of stretch receptors) - Roux-en-Y gastric bypass (RGB) - Avoid duodenum - Food in small intestine is undigested  get fewer calories - Biliopancreatic diversion (BPD) - Reduce size of stomach and essentially eliminate small intestine  can’t absorb nutrients ~ Problems? - Problems with these: - Malabsorptive operations most effective but have greatest risk for nutritional deficiencies (B12, Iron, Calcium) - Nausea is the most common complaint - Absorption of fat and soluble vitamins impaired - Dumping syndrome - Gallstones: decreases sensitivity of gallbladder so bile sits in ducts for long periods and forms stones - Increased risk of iron, calcium and vitamin B12 deficiency - Can’t produce intrinsic factor needed to make B12 - Iron and calcium need acidic medium for max absorption ~ Theories of Eating Behavior 1. Blood Glucose Hypothesis  Hunger decreases when amount of food glucose in blood is high

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Problem: diabetic people always have high blood glucose but still hungry 2. Glucostatic Hypothesis  Hunger based on glucose utilization  When difference between arterial and venous glucose levels, you feel full  Based on insulin – insulin causes cells to absorb glucose  arterial glucose will be high but venous glucose will be low  Problem: anticipation of a meal increases insulin therefore you would be full before you eat and poor correlation in studies 3. Central Theories of Eating: Hypothalamus  VMH: lesions cause overeating and stimulation causes anorexia and wasting i. Satiety Center  LH: lesions cause anorexia and wasting and stimulation cause obesity and overeating  However, Kennedy showed what hypothalamus really regulation of body fat  set point theory – brain determines set body weight and you will always return back to this weight i. Adipose cell sends feedback to hypothalamus ~ Minimizing the risk of atherosclerosis  Maintain vitamin E levels (BUT no benefit of supplements)  fewer heart attacks o Vitamin E blocks oxidation  Exercise to raise HDL levels o Properties of HDL; antioxidant, anti-inflammatory o Exercising raises HDL, decreases blood pressure, and decreases need for insulin  1 alcoholic beverage per day – raises HDL levels o Alcohol stimulates HDL production ~ Estimating Energy Content of Food  Bomb calorimeter o Oxidize container with food, water on outside of container  energy in food is oxidized and heat produced raises temperature of water o Dried sample  oxygen  spark  measure rise in temperature (directly calculate calories!) ~ Estimating Energy Expenditure – indirect Calorimetry  Respiratory Analysis  Respirator quotient = CO2 expired/O2 consumed o Glucose = 6 CO2/6 O2 = 1, fatty acids = 0.7 o Ranges from 0.7 (burning pure fats) to 1 (burning pure carbohydrates) o Can calculate energy expenditure:

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If you know either rate of oxygen consumed or rate of carbon dioxide expired AND RQ you can find energy expenditure  *can’t be measured for a long period of time Really measuring ATP production Estimate ATP utilization

~ Methods of indirect Calorimetry  Double labeled water o Label hydrogen and oxygen with NON-radioactive labels o Hydrogen is lost in H20 o Oxygen is lost in H20 and C02 (last faster than hydrogen since lost in two forms) o (CO2 +H2O)- H2O=C02 o Rate of oxygen lost - rate of hydrogen lost = (water + carbon dioxide) water= carbon dioxide o With RQ, can calculate metabolic rate o Can estimate RQ from food quotient o Best technique and most sensitive  Heart Rate Monitor o Indicator of energy expenditure o Can measure this over a period of time o Problems:  Must acquire individual heart rate curves  Curves change with physical conditioning-more fit you are, less heart rate responds  Food Quotient o Good approximation of the RQ- look at fat and carbohydrates consumed in food logs o If you know the RQ and the CO2 expelled you can calculate ATP produced ~ Estimating Energy Expenditure – direct Calorimetry • Put in room with heat sensors in wall • Heat sensors measure heat radiated from the body • Very accurate but can’t measure expenditure for long periods of time and behaviors are restricted (under surveillance so activities may deviate from a normal routine) • Also very expensive ~ Lavoisier • If the ratio of CO2 expelled to O2 used is known, one can calculate energy expenditure • Placed guinea pigs in a container filled with ice • Placed an oil lamp in a second container and used this for comparison

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Found that the oxidation of oil in the chamber containing the oil lamp mimicked that of the guinea pig Heat released by the guinea pigs caused the ice to melt Water and carbon dioxide were collected from the container...