Body Temperature

Question 1

homeothermic

Answer 1

maintaining a relatively constant body temperature, independent of the temperature of the surrounding environment

Question 2

metabolism

Answer 2

makes use of mitochondria to produce energy

Question 3

core temperature

Answer 3

warm, internal

Question 4

shell temperature

Answer 4

cool, external

Question 5

thermoregulation

Answer 5

ability to maintain a constant body temperature despite external temperature changes

temperature regulating centers located in the hypothalamus

Question 6

mechanisms of heat exchange

Answer 6

used to maintain homeostasis when the body isn’t thermoneutral

Question 7

radiation

Answer 7

transfer of heat without contact, from an object to its environment and visa versa via infrared rays

Question 8

evaporation

Answer 8

transfer of heat due to evaporation of water

only way to regulate body temperature when external environment is >37*C

major heat loss mechanism

Question 9

conduction

Answer 9

exchange of heat between objects of different temperatures that are in direct contact

Question 10

convection

Answer 10

transfer of heat through circulation of air currents or liquid along the skin surface

Question 11

heat loss

Answer 11

depends on the blood flow through the skin capillaries

promoted by vasodilation

Question 12

metabolism

Answer 12

major source of internal heat generation

non-hypothalamic

Question 13

shivering thermogenesis

Answer 13

skeletal muscle metabolism

somatic neurons activated

Question 14

non-shivering thermogenesis

Answer 14

brown fat metabolism

SNS activated to release norepinephrine which activates the uncoupling protein for the mitochondrial and oxidative phosphorylation uncoupling

Question 15

brown fat

Answer 15

used in response to cold as it has many mitochondria that can be used for energy (heat) production

Question 16

heat conservation

Answer 16

vasoconstriction
piloerection
behavioral changes

Question 17

anterior hypothalamus

Answer 17

heat loss center

warm-sensing neurons

excited by increase in temperature

stimulates sweating and vasodilation

Question 18

posterior hypothalamus

Answer 18

heat gain center

cold-sensing neurons

excited by decrease in temperature

stimulates conservation, and shivering and non-shivering thermogenesis

Question 19

thermoreceptors

Answer 19

sensory neurons monitor skin and core temperature then send information to the hypothalamus

Question 20

peripheral thermoreceptors

Answer 20

found in the skin

Question 21

central thermoreceptors

Answer 21

found in the hypothalamus, viscera, and veins

Question 22

sympathetic nervous system

Answer 22

acts on smooth vascular muscle via vasomotor neurons to control vasodilation and vasoconstriction

Question 23

AV shunts

Answer 23

short vessels that connect small arteries and small veins

Question 24

cholinergic neurons

Answer 24

bind to acetylcholine which induces vasodilation and causes sweating

Question 25

adrenergic neurons

Answer 25

bind to epinephrine and norepinephrine which induces vasoconstriction and causes heat conservation activates cAMP

Question 26

eccrine sweat glands

Answer 26

occur over most of the body open directly onto the surface of the skin

Question 27

apocrine sweat glands

Answer 27

open into hair follicles leading to the skin surface

Question 28

hyperthermia

Answer 28

body's temperature rises abnormally high without a change in set point failure of heat regulating mechanisms - not able to lose heat

Question 29

heat exhaustion

Answer 29

high core temperature (37.8-39*C) severe dehydration due to sweating caused by vigorous exercise in hot humid climates

Question 30

heat stroke

Answer 30

extremely high core temperature (>41*C) fatal hyperthermia caused by heat exposure through environmental factors and physical exercise

Question 31

heat cytotoxicity

Answer 31

cytokines released by heat-stressed cells cause local and systemic inflammation and multiple organ failure during heat stroke

Question 32

malignant hyperthermia

Answer 32

autosomal dominant genetic disorder abnormally elevated temperature (44.5*C max) uncontrolled skeletal muscle contractions triggered by anesthetic agents

Question 33

rhabdomyolysis

Answer 33

breakdown of muscle tissue releasing toxic protein (myoglobin) into the blood that results in kidney damage and brown urine which is a symptom of malignant hyperthermia

Question 34

hypothermia

Answer 34

core temperature falls below 35*C body fails to produce enough heat hypothalamus cannot thermoregulate

Question 35

mild hypothermia

Answer 35

32-35*C shivering increased pulse and breathing dehydration

Question 36

moderate hypothermia

Answer 36

28-32*C decreased shivering rigid muscles decreased pulse and breathing

Question 37

severe hypothermia

Answer 37

<28*C coma no pupillary reflex slugging of RBCs

Question 38

passive external rewarming

Answer 38

remove from cold remove wet clothes cover with blankets supply warm fluids

Question 39

active external rewarming

Answer 39

immerse in warm water heat with air warmers heating pads or hot water bottles

Question 40

invasive active core rewarming

Answer 40

warm fluids pumped into stomach extracorporeal blood rewarming** inhalation of warm O2 warm IV fluids

Question 41

frostbite

Answer 41

localized hypothermic injuries

Question 42

tissue freezing

Answer 42

ice crystals form extracellularly causing cellular dehydration and shrinkage microvascular blood flow occlusion leads to ischemia and thrombosis resulting in tissue damage

Question 43

artificial hypothermia

Answer 43

induced artificially during surgery using sedatives (21-24*C)

Question 44

fever/pyrexia

Answer 44

elevation of body temperature above normal (37-39*C) as a result of the hypothalamic thermostat being reset due to an immune response

Question 45

pyrogens

Answer 45

fever reducing substances

Question 46

exogenous pyrogens

Answer 46

not bodily derived produced by pathogens

Question 47

endogenous pyrogens

Answer 47

bodily derived released in response to exogenous pyrogens produced by leukocytes and macrophages

Question 48

metabolic shift during fever

Answer 48

glucose is a bacterial growth medium so switch to protein and fat breakdown prolonged fever results in fat loss due to high levels of ketones that lead to metabolic acidosis

Question 49

antipyretics

Answer 49

drugs that lower fever by resetting the set point to lower or normal values inhibits PGE2 production by inhibiting COX-2