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40 Cards in this Set
- Front
- Back
what percentage of the human body's energy is used for work? the remaining percentage is used for? |
15-30; converted into heat |
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what is the typical resting core temp |
37C (98.6F) |
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humans either ____ or ___ heat depending on how close your core is to your typical resting level |
retain; dissipate |
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neuro-endocrine organ responsible for maintaining core temp as close as possible to 37 C |
hypothalamus |
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what other four functions besides core temp regulation is the hypothalamus in charge of? |
water balance, sugar and fat catabolism, satiety center, controls other endocrine gland |
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if looking at the side of your head, at what spot would the hypothalamus be? |
temple |
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The temp regulation centers collectively function as a _______ and are situated on the _______ aspect for hypothermia and the _______ for hyperthermia. |
bi-directional thermostat; posterior; anterior |
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when core temperature is too low, what two mechanisms are used by the temp centers hypothalamus to return the core temp back to normal? |
heat conservation and increased heat production |
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How is heat conservation initiated? |
decreased sweat rate and decreased blood flow to extremeties and to skin's surface |
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what term means a decreased bloodflow to the skin's surface? |
dermal vasoconstriction |
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List three ways in which the body will increase heat generation when core body temp is too low. |
shivering (SNS increases catabolic rate 2-4 times over resting level), hypothalamus triggers thyroid gland to produce thyroxin which increases catabolic rate, hypothalamus triggers adrenals to release catacholamines which also increase catabolic rate |
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Through which two ways does the anterior hypothalamus attempt to decrease body temp when it gets too high? |
heat dissipation and decreased heat production |
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what are two precursors to heat dissipation? |
increased sweat rate and increased blood flow to extremeties and skin's surface |
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what is the term for increased bloodflow to skin's surface? |
dermal vasodilation |
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after one or more of the precursors to heat dissipation have been activated, what are the four ways that heat can be released? |
conduction, convection, radiation, and evaporation |
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each gram of vaporized water from evaporation disspates ~ ____ kcal of heat energy. This is called the ____ or ______. |
.58; energy of vaporization; heat of vaporization |
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How does the body decrease heat production? |
by decreasing the metabolic rate |
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List three differences between men and women in regards to heat dissipation. |
females have more sweat glands, ~10% more body fat, and have lower max O2 uptakes |
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The lower the VO2max, the _____ the efficiency of heat dissipation mechanisms. |
lower |
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females generallly respond to elevated core temps with dermal vasodilation greater than or less than males? |
greater than |
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generally speaking, men rely on ______ to dissipate heat to a greater extent than females, and females rely on ____, ____, and _____ to dissipate heat more than males |
evaporation; conduction, convection, and radiation |
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Does dehydration result in an increase in plasma protein and electrolyte concentrations or a decrease? Why? |
increase; due to a substantial loss of plasma water |
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A decrease in total blood volume results in what with the heart: an increase in stroke volume, or decrease? |
decrease |
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In order to maintain cardiac output (Q) during submaximal exercise, heart rate must be _____ during dehydration when compared to euhydrated state. |
increased |
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If a decrease in blood volume results in a subsequent decrease in peripheral blood flow, what does this mean for heat dissipation? What does this mean for your core temp? |
reduces the potential for heat dissipation through conduction, convection, and radiation; it rises |
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A _____% decrease in body wt via dehydration reduces physical work capacity and local muscular endurance. |
5 |
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How is strenght affected by dehydration |
minimally (except in extreme cases) |
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____ lbs of body weight from fluid losses ~ 1 pint of water |
1 |
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condition in which the amount of sodium in the blood is lower than normal |
hyponatremia |
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Name two reasons the body needs sodium |
since sodium is mostly found in the body fluids outside the cell, it is important for blood pressure, and also needed for nerves, muscles, and other body tissues to work properly |
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What causes hyponatremia? |
when level of sodium in fluids outside of cells drops, water moves into the cells to balance levels, and the result is the cells swelling with too much water |
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three types of hyponatremia |
euvolemic hyponatremia, hypervolemic hyponatremia, hypovolemic hyponatremia |
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type of hyponatremia in which total body water increases, but the body's sodium content stays the same |
euvolemic hyponatremia |
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type of hyponatremia in which both sodium and water levels in the body increase, but the water gain is greater |
hypervolemic hyponatremia |
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type of hyponatremia in which water and sodium are both lost from the body, but the sodium loss is greater |
hypovolemic hyponatremia |
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Name the three characteristics of heat acclimation |
sweating at lower core temps, sweting more at higher core temps, hypotonic sweat |
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name two feats a heat acclimated person will accomplish |
store less heat during the initial phases of exercise and reach a lower thermal steady state |
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each g of albumin binds with ____ ml of blood plasma |
13 |
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a fully heat-acclimated person will have retained ~ ___% more plasma than in the non-acclimated state because of increased _______ levels |
20;albumin |
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The blood-volume adaptation of a heat acclimated person is completed w/in ____ weeks. |
2 |