Exam 4 Lesson 15 What kind of metabolic changes occur during the absorptive and postabsorptive states Absorptive state is the period following a meal when nutrient absorption is under way Postabsorptive state is the period when nutrient absorption is not under way Requires the body to rely on internal energy reserve for energy Liver cells conserve glucose and breaks down lipids and amino acids How are ketone bodies formed What is it indicative of What happens if there are too many ketone bodies in your bloodstream When the body is lacking glucose it catabolizes lipids and amino acids to generate acetyl CoA Increase concentration of acetyl CoA causes ketone bodies to form Too many ketone bodies in bloodstream can cause Ketonemia Ketoacidosis is a significant drop in blood pH cause by high ketone levels severe ketoacidosis may cause coma cardiac arrhythmias and death What types of foods contain all the essential amino acids What types of foods are lacking in one or more essential amino acids If you are a vegetarian what type of dietary change can be made to prevent malnutrition Five basic food groups grains veggies fruits milk products meats and beans Complete proteins provide all essential amino acids in sufficient quantities found in beef fish poultry eggs and milk Incomplete proteins are deficient in one or more essential amino acids found in plants vitamin B12 not in plants but is in tofu What are N compounds and why are they important Where do you obtain N compounds N Compounds are not stored in the body and must be obtained by recycling N compounds in body or from diet Compounds include Purines pyrimidines nitrogenous bases of RNA and DNA Amino acids framework of all proteins glycoproteins and lipoproteins Creatine energy storage in muscle creatine phosphate Porphyrins bind metal ions essential to hemoglobin myoglobin and cytochromes Nitrogen balance nitrogen absorbed from diet balances nitrogen lost in urine and feces Positive Nitrogen Balance individuals actively synthesizing N compounds need to absorb more nitrogen than they excrete Ex Growing children athletes and pregnant women Negative Nitrogen Balance when excretion exceeds ingestion Why are minerals and vitamins important What roles do they play in metabolic reactions Minerals are inorganic ions released through dissociation of electrolytes Important for 3 reasons 1 2 3 Ions such as sodium chloride and potassium determine osmotic concentrations of body fluids Ions play a major role in physiologic processes Ions are essential cofactors in many enzymatic reactions Metals each component of the electron transport system requires an iron atom final cytochrome protein of ETS requires a copper ion Mineral reserves help reduce effects of variations in diet excess in mineral can be dangerous since storage capacity is limited Which vitamins can be stored by the body What are the fat soluble vitamins and why are they important What is the function of vitamin B12 What is required for its absorption A vitamin is an essential organic nutrient that functions as a coenzyme in vital enzymatic reactions 1 Fat soluble absorbed primarily from the digestive tract normally diffuse into plasma membrane and lipids in liver and adipose tissue Vitamin A structural component of visual pigment retinal Vitamin D produced by skin in sunlight is converted to calcitriol which increases the rate of intestinal calcium and phosphorus absorption Vitamin E stabilizes intracellular membranes Vitamin K helps synthesize several proteins including 3 clotting factors and some is produced by intestinal bacteria 2 Water soluble are components of coenzymes are rapidly exchanged between fluid in digestive tract and circulating blood excesses are excrete in urine unlike stored fat soluble Vitamin B12 intestinal epithelium absorbs all water soluble vitamin except B12 The molecule is too large and must bind to intrinsic factor before absorption Lack of B12 hinders RBC production causing pernicious anemia Avitaminosis vitamin deficiency disease very rare in fat soluble vitamins Hypervitaminosis is more likely What is the difference between a calorie and a Calorie What type of molecule has the most chemical energy per gram of that molecule Energy required to raise 1 g of water 1 degree Celsius is a calorie cal Energy required to raise 1 kilogram of water 1 degree Celsius is a Calorie Cal kilocalorie kcal Energy content Lipids 9 46 Cal g Carbs 4 18 Cal g Proteins 4 32 Cal g What are some techniques for measuring metabolic rate Metabolic rate is the sum of all anabolic and catabolic processes in the body If daily energy intake exceeds energy demands body stores excess energy as triglycerides in adipose tissue If daily caloric expenditure exceeds dietary supply body uses energy reserves loses weight Basal Metabolic Rate BMR is the minimum resting energy expenditure Is measured by monitoring respiratory activity T4 Assay measures thyroxine in blood to measure metabolism Hormonal Effects Cholecystokinin CCK and adrenocorticotropic hormone ACTH released by Leptin is released by adipose tissues during absorptive state and binds to CNS adrenal gland suppress appetite neurons that suppress appetite Why is thermoregulation important to the body Is it always held at a constant temperature What can cause changes to normal body temperature Thermoregulation Increased physical or metabolic activity generates more heat Body produces heat as by product of metabolism Heat produced is retained by water in body Body controls heat gains and losses to maintain homeostasis For body temp to remain constant heat must be lost to environment Heat production BMR estimates rate of energy use energy not captured is released as heat mechanisms Enzymes operated in a limited temperature range controlled by homeostatic Lesson 16 What are the components of the digestive system Which are classified as primary digestive organs and which are classified as accessory organs Primary organs Oral cavity teeth tongue pharynx esophagus stomach small intestine and large intestine Accessory organs Salivary glands liver gallbladder pancreas What are the six functions of the digestive system Ingestion when material enter digestive tract via the mouth 1 2 Mechanical processing crushing and shearing makes materials easier to propel along digestive tract digestive epithelium 3 Digestion chemical breakdown of food into small organic fragments for absorption by 4 Secretion the release of water acids enzymes buffers and
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