A & P Exam 3 - Ch. 24
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CamilleBurt on July 12, 2010
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exam material from chapter 24
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30 terms
Terms | Definitions |
|---|---|
 nutrient | a substance in food that promotes normal growth, maintenance, and repair |
| essential use of lipids in the body | 1. help absorb fat-soluble vitamins 2. major fuel of hepatocytes and skeletal muscle 3. phospholipids are essential in myelin sheaths and all cell membranes |
| use of amino acids in the body | 1. all-or-none rule 2. adequacy of caloric intake 3. nitrogen balance 4. hormonal controls |
| seven minerals required in moderate amounts | calcium phosphorus potassium sulfur sodium chloride magnesium |
| two types of metabolic reactions | anabolism: synthesis of large molecules from small ones catabolism: hydrolysis of complex structures to simpler ones |
| stages of metabolism | 1. digestion, absorption, and transport to tissues 2. cellular processing (in cytoplasm) 3. oxidative (mitachondrial) breakdown of intermediates into CO2, water, and ATP |
| substrate-level phosphorylation | high-energy phosphate groups directly transferred from phosphorylated substrates to ADP |
| glycolysis | occurs in the cytosol |
| Krebs cycle | 1. occurs in the mitachondria 2. makes 4 ATP 3. uses 2 ATP for a net gain of 2 ATP |
| during electron transport chain and oxidative phosphorylation | ATP synthase uses released energy to make ATP |
| 1 glucose molecule | nets 32 ATP |
| glycogenesis | glycogen formation when glucose supplies exceed need for ATP synthesis |
| Glycogenolysis | glycogen breakdown in response to low blood glucose |
| glycerol | 1. enters the Krebs cycle 2. equivalent to 1/2 glucose |
| protein synthesis | 1. hormonally controlled 2. requires a complete set of amino acids -essential amino acids must be provided in the diet |
| absorptive (fed) state | -during and shortly after eating -absorption of nutrients is occurring |
| postabsorptive (fasting) state | -when the GI tract is empty -energy sources are supplied by breakdown of reserves |
| insulin | a hypoglycemic hormone, enhances: -facilitated diffusion of glucose into muscle and adipose tissue -glucose oxidation -glycogen and triglyceride formation -active transport of amino acids into tissue cells for protein synthesis |
| sources of blood glucose | 1. glycogenolysis in the liver 2. glycogenolysis in skeletal muscle 3. lipolysis in adipose tissues and the liver 4. catabolism of cellular protein during prolonged fasting |
| glucagon | -does the opposite of insulin -a hyperglycemic hormone -promotes: 1. Glycogenolysis and gluconeogensis in the liver 2. lipolysis in adipose tissue 3. modulation of glucose effects after a high- protein, low-carbohydreate meal |
| lipoproteins | -VLDLs -LDLs -HDLs |
| VLDLs | transport triglycerides to peripheral tissues (mostly adipose) |
| LDLs | transport cholesterol to peripheral tissues for membranes, storage, or hormone synthesis; increase the risk of heart attack; need some, but excessive amounts not good |
| HDLs | transport excess cholesterol from peripheral tissues to the liver to be broken down and secreted into bile; protect against heart attack |
| heat energy | -cannot be used to do work -warms the tissues and blood -helps maintain the homeostatic body temperature -allows metabolic reactions to occur efficiently |
| leptin | hormone secreted by fat cells in response to increased body fat mass |
| normal body temperature | - 37 C +/- 5 C (98.6 F) - optimal enzyme activity occurs at this temperature - increased temperature denatures proteins and depresses neurons |
| __________ is the major agent of heat exchange between the core and the shell | blood |
| 4 mechanisms of heat exchange | 1. radiation - the loss of heat in the form of infrared rays 2. conduction - the transfer of heat by direct contact 3. convection - the transfer of heat to the surrounding air 4. evaporation - the heat loss due to evaporation of water from body surfaces |
| heat promoting mechanisms | - constriction of cutaneous blood vessels -shivering -increased metabolic rate via epinephrine and norepinephrine -enhanced thyroxine release -voluntary measures: ~putting on more clothes ~drinking hot fluids ~changing posture or increasing physical activity |
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