Term
| 2 hypothalamic centers on which behavioral regulation of food intake is based |
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Definition
1. feeding center (tonically active)
2. satiety center (stops food intake by inhibiting the feeding center) |
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Term
| What tissue secretes adipocytokines (chemical signals that influence food intake & satiety)? |
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Definition
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Term
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Definition
| glucose metabolism by hypothalamic centers regulates food intake |
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Term
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Definition
| a signal from the body's fat stores to the brain modulates eating behavior so that the body maintains a particular weight |
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Term
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Definition
| a protein hormone synthesized in adipocytes that provides evidence for the lipostatic theory; discovered in 1994 |
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Term
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Definition
| a brain neurotransmitter that seems to be the stimulus for food intake |
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Term
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Definition
| a peptide secreted by the stomach during fasting & increases hunger when infused into human subjects |
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Term
| equation for total body energy |
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Definition
| total body energy = energy stored + energy intake - energy output |
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Term
| equation for energy output |
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Definition
| energy output = work + heat |
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Term
| 3 types of work that contribute to energy output |
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Definition
1. transport work (moves molecules from one side of a membrane to the other)
2. mechanical work (uses intracellular fibers & filaments to create movement)
3. chemical work (used for growth, maintenance, & storage of information & energy) |
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Term
| What is the most direct way to measure the energy content of food? |
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Definition
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Term
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Definition
| the amount of heat needed to raise the temperature of 1 liter of water by 1 degree C |
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Term
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Definition
| an individual's energy expenditure; measuring this is more complex than figuring the caloric content of ingested food |
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Term
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Definition
| the rate at which the body consumes oxygen as it metabolizes nutrients; the most common method for estimating metabolic rate |
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Term
| Is measuring oxygen consumption an example of direct calorimetry or indirect calorimetry? |
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Definition
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Term
| respiratory quotient (RQ) / respiratory exchange ratio (RER) |
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Definition
| the ratio of CO2 produced to O2 consumed |
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Term
| equation for metabolic rate (in kcal/day) |
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Definition
| metabolic rate = L O2 consumed/day X kcal metabolized/L O2 |
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Term
| basal metabolic rate (BMR) |
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Definition
| an individual's lowest metabolic rate |
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Term
| resting metabolic rate (RMR) |
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Definition
| metabolic rate after a 12-hour fast in a person who is awake but resting; used because measuring the BMR of a sleeping person is difficult |
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Term
| 6 factors that affect metabolic rate in humans |
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Definition
1. age & sex
2. amount of lean muscle mass
3. activity level
4. diet
5. hormones
6. genetics |
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Term
| diet-induced thermogenesis |
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Definition
| the phenomenon where resting metabolic rate increases after a meal |
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Term
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Definition
| the sum of all chemical reactions in the body |
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Term
| 3 things that the reactions making up metabolic pathways do |
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Definition
1. extract energy from nutrients
2. use energy for work
3. store excess energy so that it can be used later |
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Term
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Definition
| metabolic pathways that synthesize large molecules from smaller ones |
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Term
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Definition
| metabolic pathways that break large molecules into smaller ones |
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Term
| fed state / absorptive state |
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Definition
| the period of time following a meal, when the products of digestion are being absorbed, used, & stored |
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Term
| fasted state / postabsorptive state |
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Definition
| once nutrients from a recent meal are no longer in the bloodstream & available for use by the tissues |
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Term
| 3 things that biomolecules we ingest are destined for |
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Definition
1. energy
2. synthesis
3. storage |
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Term
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Definition
| nutrients that are available for immediate use |
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Term
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Definition
| the synthesis of glycogen from glucose |
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Term
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Definition
| when additional excess glucose (due to limited glycogen stores) is converted to fat |
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Term
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Definition
| when the body converts glycogen to glucose if plasma glucose concentrations decrease |
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Term
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Definition
| when amino acids can be converted into glucose if glucose intake is low |
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Term
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Definition
| an enzyme bound to the capillary endothelium of muscles & adipose tissue that converts the triglycerides to free fatty acids & glycerol when the lipid complexes begin to circulate through the blood |
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Term
| 7 steps of fat synthesis: transport & fate of dietary fats |
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Definition
1. bile salts help break down dietary fats into components that can be absorbed
2. intestinal epithelial cells assemble absorbed cholesterol, lipoproteins, & lipid complexes into chylomicrons
3. chylomicrons are transported to the blood via the lymphatic vessels
4. lipoprotein lipase converts triglycerides into free fatty acids & glycerol
5. adipose cells reassemble the fatty acids & glycerol into triglycerides for storage
6. chylomicron remnants & HDL-C enter the liver for further processing, creating lipoprotein complexes such as LDL & VLDL
7. LDL-C is transported via the blood to most of the cells, where the cholesterol is used for synthesis |
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Term
| 3 steps of fat synthesis: triglyceride & cholesterol synthesis from glucose |
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Definition
1. glycerol can be made from glucose through glycolysis
2. fatty acids are made when 2-carbon acyl units from acetyl CoA are linked together
3. one glycerol plus 3 fatty acids make a triglyceride |
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Term
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Definition
| the removal of the amino group from the amino acids |
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Term
| 4 parts of fasted state metabolism |
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Definition
1. liver glycogen becomes glucose
2. adipose lipids become free fatty acids & glycerol that enter blood
3. muscle glycogen can be used for energy
4. brain can use only glucose & ketones for energy |
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Term
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Definition
| what the liver converts ammonia & ammonium ions into because they are toxic |
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Term
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Definition
| when the fasted-state body needs to use stored energy so lipases break down triglycerides into glycerol & fatty acids |
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Term
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Definition
1. lipases digest triglycerides into glycerol & 3 fatty acids
2. glycerol becomes a glycolysis substrate
3. beta-oxidation chops 2-carbon acyl units off the fatty acids
4. acyl units become acetyl CoA & can be used in the citric acid cycle |
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Term
| What do excess acyl units become if fatty acid breakdown produces acetyl CoA faster than the citric acid cycle can metabolize it? |
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Definition
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Term
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Definition
| small clusters of cells scattered throughout the body of the pancreas; described by Paul Langerhans in 1869 |
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Term
2 things that beta cells produce
*beta cells are a type of islet cells (75%)* |
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Definition
1. insulin
2. amylin (a peptide) |
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Term
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Definition
| the type of islet cells that secrete glucagon; make up 20% of islet cells |
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Term
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Definition
| the type of islet cells that secrete somatostatin |
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Term
| 5 factors that influence insulin secretion |
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Definition
1. increased plasma glucose
2. increased plasma amino acids
3. feedforward effects of GI hormones
4. parasympathetic activity
5. sympathetic activity |
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Term
| insulin-receptor substrates |
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Definition
| proteins that are phosphorylated by activated by insulin receptors |
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Term
| 5 steps in insulin's cellular mechanism of action |
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Definition
1. insulin binds to tyrosine kinase receptor
2. receptor phosphorylates insulin-receptor substrates
3. second messenger pathways alter protein synthesis & existing proteins
4. membrane transport is modified
5. cell metabolism is changed |
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Term
| 4 ways insulin lowers plasma glucose |
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Definition
1. insulin increases glucose transport into most insulin-sensitive cells
2. insulin enhances cellular utilization & storage of glucose
3. insulin enhance utilization of amino acids
4. insulin promotes fat synthesis |
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Term
| What is the most common pathology of the pancreatic endocrine system? |
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Definition
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Term
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Definition
| the loss of water in the urine due to unreabsorbed solutes |
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Term
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Definition
| the common hallmark of type 2 diabetes; the delayed response to an ingested glucose load seen in the 2-hour oral glucose tolerance test |
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Term
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Definition
| a peptide hormone that is co-secreted with insulin |
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Term
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Definition
| bodies that regulate internal temperature within a relatively narrow range |
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Term
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Definition
| the transfer of heat between objects that are in contact with each other; ex) the skin & a heating pad or the skin & hot water |
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Term
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Definition
| the loss of body heat to a cooler object that is touching the body; ex) an icepack or a cold stone bench |
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Term
| How must of heat lost from a person at rest in a normal room is accounted for by radiant heat loss? |
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Definition
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Term
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Definition
| the process in which heat is carried away by warm air rising from the body's surface; enhances radiant & conductive heat loss |
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Term
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Definition
| takes place as water evaporates at the skin's surface & in the respiratory tract |
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Term
| 2 places where thermoreceptors are located |
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Definition
1. peripherally in the skin
2. centrally in the anterior hypothalamus |
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Term
| What type of neurons mediate active cutaneous vasodilation? |
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Definition
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Term
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Definition
| the body uses shivering to generate heat |
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Term
| nonshivering thermogenesis |
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Definition
| metabolic heat production by means other than shivering |
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Term
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Definition
| chemicals released by various immunocytes in response to toxins from bacteria & other pathogens |
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Term
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Definition
| a condition in which body temperature rises to abnormally high values; ex) heat exhaustion & heat stroke |
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Term
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Definition
| severe dehydration & core body temperatures of 37.5-39 degrees C |
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Term
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Definition
| a more severe form of hyperthermia with higher core body temperatures |
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Term
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Definition
| body temperature becomes abnormally elevated due to genetics |
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Term
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Definition
| a condition in which body temperature falls abnormally low |
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