Ex Phys Test 3 Human Thermal Regulation

Front 1

what percentage of the human body's energy is used for work? the remaining percentage is used for?

Back 1

15-30; converted into heat

Front 2

what is the typical resting core temp

Back 2

37C (98.6F)

Front 3

humans either ____ or ___ heat depending on how close your core is to your typical resting level

Back 3

retain; dissipate

Front 4

neuro-endocrine organ responsible for maintaining core temp as close as possible to 37 C

Back 4

hypothalamus

Front 5

what other four functions besides core temp regulation is the hypothalamus in charge of?

Back 5

water balance, sugar and fat catabolism, satiety center, controls other endocrine gland

Front 6

if looking at the side of your head, at what spot would the hypothalamus be?

Back 6

temple

Front 7

The temp regulation centers collectively function as a _______ and are situated on the _______ aspect for hypothermia and the _______ for hyperthermia.

Back 7

bi-directional thermostat; posterior; anterior

Front 8

when core temperature is too low, what two mechanisms are used by the temp centers hypothalamus to return the core temp back to normal?

Back 8

heat conservation and increased heat production

Front 9

How is heat conservation initiated?

Back 9

decreased sweat rate and decreased blood flow to extremeties and to skin's surface

Front 10

what term means a decreased bloodflow to the skin's surface?

Back 10

dermal vasoconstriction

Front 11

List three ways in which the body will increase heat generation when core body temp is too low.

Back 11

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

Front 12

Through which two ways does the anterior hypothalamus attempt to decrease body temp when it gets too high?

Back 12

heat dissipation and decreased heat production

Front 13

what are two precursors to heat dissipation?

Back 13

increased sweat rate and increased blood flow to extremeties and skin's surface

Front 14

what is the term for increased bloodflow to skin's surface?

Back 14

dermal vasodilation

Front 15

after one or more of the precursors to heat dissipation have been activated, what are the four ways that heat can be released?

Back 15

conduction, convection, radiation, and evaporation

Front 16

each gram of vaporized water from evaporation disspates ~ ____ kcal of heat energy. This is called the ____ or ______.

Back 16

.58; energy of vaporization; heat of vaporization

Front 17

How does the body decrease heat production?

Back 17

by decreasing the metabolic rate

Front 18

List three differences between men and women in regards to heat dissipation.

Back 18

females have more sweat glands, ~10% more body fat, and have lower max O2 uptakes

Front 19

The lower the VO2max, the _____ the efficiency of heat dissipation mechanisms.

Back 19

lower

Front 20

females generallly respond to elevated core temps with dermal vasodilation greater than or less than males?

Back 20

greater than

Front 21

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

Back 21

evaporation; conduction, convection, and radiation

Front 22

Does dehydration result in an increase in plasma protein and electrolyte concentrations or a decrease? Why?

Back 22

increase; due to a substantial loss of plasma water

Front 23

A decrease in total blood volume results in what with the heart: an increase in stroke volume, or decrease?

Back 23

decrease

Front 24

In order to maintain cardiac output (Q) during submaximal exercise, heart rate must be _____ during dehydration when compared to euhydrated state.

Back 24

increased

Front 25

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?

Back 25

reduces the potential for heat dissipation through conduction, convection, and radiation; it rises

Front 26

A _____% decrease in body wt via dehydration reduces physical work capacity and local muscular endurance.

Back 26

5

Front 27

How is strenght affected by dehydration

Back 27

minimally (except in extreme cases)

Front 28

____ lbs of body weight from fluid losses ~ 1 pint of water

Back 28

1

Front 29

condition in which the amount of sodium in the blood is lower than normal

Back 29

hyponatremia

Front 30

Name two reasons the body needs sodium

Back 30

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

Front 31

What causes hyponatremia?

Back 31

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

Front 32

three types of hyponatremia

Back 32

euvolemic hyponatremia, hypervolemic hyponatremia, hypovolemic hyponatremia

Front 33

type of hyponatremia in which total body water increases, but the body's sodium content stays the same

Back 33

euvolemic hyponatremia

Front 34

type of hyponatremia in which both sodium and water levels in the body increase, but the water gain is greater

Back 34

hypervolemic hyponatremia

Front 35

type of hyponatremia in which water and sodium are both lost from the body, but the sodium loss is greater

Back 35

hypovolemic hyponatremia

Front 36

Name the three characteristics of heat acclimation

Back 36

sweating at lower core temps, sweting more at higher core temps, hypotonic sweat

Front 37

name two feats a heat acclimated person will accomplish

Back 37

store less heat during the initial phases of exercise and reach a lower thermal steady state

Front 38

each g of albumin binds with ____ ml of blood plasma

Back 38

13

Front 39

a fully heat-acclimated person will have retained ~ ___% more plasma than in the non-acclimated state because of increased _______ levels

Back 39

20;albumin

Front 40

The blood-volume adaptation of a heat acclimated person is completed w/in ____ weeks.

Back 40

2