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42 Cards in this Set
- Front
- Back
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Conduction |
heat transfer by means of physical contact between two surfaces of different temperatures |
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Convection |
movement of heat by the movement of a fluid (liquid or gas) across a surface
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Radiation |
emission of heat as electromagnetic radiation |
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Evaporation |
a cooling mechanism by which the animal loses water molecules to the vapor state that are more energetic than the mean energy of the remaining molecules. ex. sweating, panting |
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Ectotherm |
- animal whose body temp. is determined mainly by heat exchange with the environment - thermoconformers (ambient and body temp. will be the same - have no body insulation - cannot be large animals in high latitudes ( small enough to burrow) - can have smaller body sizes than endotherms - can get by with a lower metabolic rate "gigantothermy" - can undergo vasodilation - heat up - able to withstand low body temp |
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Endotherm |
-animal that maintains a favourable body temp. mainly by the internal generation of heat - thermoregulators (maintains a fairly constant body temp. with changing temp) - give themselves extra metabolic work to do (futile cycling) - high basal metabolic rate -insulated to retard the loss of heat - large body size helps retain heat - cannot be as small as smallest ectotherms (would lose heat too rapidly to replace) - can undergo vasodilation- cool down - can undergo vasoconstriction - heat |
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Heterotherm |
animal that displays either regional endothermy or temporal endothermy |
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Regional Endothermy |
increased heat generation in a certain region of the animal |
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Temporal Endothermy |
increased heat generation at a certain time. |
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Futile Cycling |
two metabolic pathways run simultaneously in opposite directions and have no overall effect other than to dissipate energy in the form of heat - endotherms do this to maintain constant body temp. |
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Homeotherm |
animal that maintains a fairly constant body temperature |
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Poikiotherm |
an animal whose body temp. varies widely. ex. humminbird (endo), desert reptiles (exo) |
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Vasodilation |
an increase in the diameter of blood vessels under the skin
in ectotherms: allows to absorb more heat from the surroundings more quickly (heating)
in endotherms: dumps heat to the outside when the animal needs to cool down
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Vasoconstriction |
-decrease in the diameter of blood vessels under the skin
in endotherms: keeps the heat in the body core when the animal needs to conserve heat. (sacrificing extremities for core) |
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Countercurrent heat exchangers |
retain body heat inside the core by collecting heat from the blood before it passes into extremities |
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Mammalian Thermostat |
- located in hypothalamus - has an adjustable set point: when temp is above, cooling measures are initiated. when temp is below, heating measures are initiated -able to integrate info about its own temp. and ambient air temp. |
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Hypothermia |
lowering of body temperature below its normal range.
regulated forms: - torpor- brief inactive state resulting from lowering of thermostat's setpoint to save energy - hibernation- prolonged inactive state resulting from a lowering of thermostats setpoint to save energy |
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Thermogeddon |
-term applied to possible future state when parts of the earth will become to hot for human life - at wet bulb temp above 35 degrees, we cannot survive for longer than a few hours -feared that global warming will bring wet bulb temp to this level - 1 deg. increase in wb temp = 0.75 deg. increase in mean global temp. |
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Hypertermia |
heat stress - if our body temp goes above 42 degrees C, we die - organ failure, slower nerve conduction, convulsions |
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Wet-bulb temperature |
temperature measured by a wet cloth around the bulb of a thermometer - takes into account our ability to cool by the evaporation of sweat - current the highest is approx. 31 degrees C |
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Climate Sensitivity |
-how high the temperature goes for doubling og CO2 in the atmosphere -possible range: 1.9-4.5 1.9= thermogeddon in 23rd century 4.5= 22nd century |
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Homeostasis |
-maintenance of a relatively stable internal environment despite changing external conditions -kept within fairly narrow ranges |
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Negative Feedback |
-type of homeostatic mechanism -response to a stimulus reduces that stimulus ex. home heating (thermostat). thermoregulation in mammals |
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Positive Feedback |
-type of homeostatic mechanism - response to a stimulus increases that stimulus - less common ex. child birth (uterine contractions--> oxytocin--> stronger contractions) |
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Feedforward Control |
- typed of homeostatic mechanism - a change occurs in the animal in anticipation of the stimulus ex. thought of food--> salivation, secretion of HCl in stomach |
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Chemoheterotroph |
-organism that obtains energy by the oxidation of electron donors (as opposed to photosynthesis) - most get from organic sources |
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Four fates of energy ingested by an animal |
1. stored (ex.glycogen fat) or used for other growth (ex.muscle) 2. used to do other work inside or outside the body 3. excreted 4. released as heat |
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Metabolic rate |
- energy use per unit time. -can be measure in several ways: heat released- kJ/min oxygen uptake - mL/min CO2 released - mL/min
- large animals have higher metabolic rates than small animals BUT small animals have higher metabolic rates per unit body mass than large animals |
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Basal metabolic rate |
the metabolic rate of an endotherm that is necessary to maintain the basic processes of life: -resting -not hibernating -not digesting food - not thermoregulating |
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Standard metabolic rate |
the metabolic rate of a a resting, fasting ectotherm at a given temp. |
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Tissue |
group of cells that cooperate closely in the performance of certain tasks and processes |
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Epithelial tissue |
-sheets of cells that enclose structures or the entire animal -acts as an interface between different structures/ the organism and it's environment - functions: containment defense- skin barrier is acidic absorption, exchange- lines organs etc. movement - some is ciliated (bronchioles etc) secretion - sweat, tears sensory detection - rod cells in eyes, hair in ear cells |
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Connective tissue |
-cells suspended in an amorphous, acellular matrix. -main function is to bind and support other tissues ex. blood, cartilage |
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Muscle tissue |
-contains cells of capable contraction, thus creating movement |
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Nervous tissue |
transmits and integrates electrical signals |
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Portal system |
when a capillary bed does not drain directly into the venous system , but into another capillary (portal system) |
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Hyperpolarization |
the inside of the cell becomes even more negative |
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Depolarization |
the inside of the cell becomes less negative |
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Systole |
contraction of a heart chamber |
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Diastole |
relaxation of a heart chamber |
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Sinoatrial node |
-the heart's natural pacemaker - initiates atrial systole - initiates a chemical signal (action potential) |
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Cardiac Output |
cardiac output = heart rate x stroke volume
how much blood the heart expels in 1 min |
