Final Exam - Thermoregulation Flashcards

1
Q

heat production

A

thermogenesis

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2
Q

heat loss

A

thermolysis

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3
Q

maintenance - thermogenesis

A

Vasoconstriction
Shivering
Piloerection
Curling up

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4
Q

maintenance - thermolysis

A

vasodilation
sweating
pilorelaxation
stretching out

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5
Q

Effect of shivering

A

increase metabolism –> similar to light exercise

increase heat production by 500%

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6
Q

Target organs of nonshivering thermogenesis

A

brown adipose tissue (BAT) + skeletal muscle

  • skeletal muscle = primary in adults
  • BAT = primary in infants
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7
Q

Net energy moves from ____ to _____

A

warmer object to cooler object

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8
Q

Mechanisms of heat loss

A

Radiation
Evaporation
Convection
Conduction

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9
Q

Latent heat of vaporization

A

Evaporization

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10
Q

Most heat loss occurs d/t

A

radiation

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11
Q

Radiation

A

Heat loss by transfer of photons

NOT to surrounding air

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12
Q

Evaporization

A

insensible water evaporation from skin/lungs

1/2 d/t respiratory loss

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13
Q

Decrease radiation heat loss by

A

incubator/barrier between patient/object

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14
Q

decrease evaporation heat loss by

A

humidification, covering exposed skin, using warm preps

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15
Q

conduction

A

heat loss thru contact with cooler object

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16
Q

conduction requires

A

direct contact

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17
Q

conduction heat loss can be minimized by

A

insulation, bair hugger, warming mattress under patient

18
Q

convection

A

heat loss thru moving cool air

19
Q

primary terminal organ for cold sensation

A

Krause’s end bulb

20
Q

Krause’s end bulb - range of stimulation

A

15-25*C

Below = only pain receptors active

21
Q

primary terminal organ for warm sensation

A

Ruffini’s Corpuscle

22
Q

Ruffinis Corpuscle - range of stimulation

A

25-45*C

23
Q

Cold sensation transmitted to spinal cord via

A

small-diameter, myelinated, A delta nerve fibers

24
Q

Warm sensation transmitted to spinal cord via

A

unmyelinated C nerve fibers

25
Q

Peripheral sensors: afferent temp

A

terminal organ –> nerve fibers –> substantia gelatinosa of posterior horn (spinal cord)
–> anterolateral spinothalmic tract to thalamus

26
Q

Central sensors: afferent temp

A

anterior hypothalamus

outside CNS: receptors in muscles + splanchnic/vagal afferents

27
Q

earliest warning of external temperature changes

A

come from peripheral temperature sensors

28
Q

central receptors take over once

A

skin temperature has reached maximum variability

29
Q

Efferent systems: involves 2 pathways

A

neurologic, endocrine

30
Q

neurologic efferent system

A

SNS regulates cutaneous blood flow/nonshivering thermogenesis via adrenergic efferents/diaphoresis (via cholinergic efferents)

31
Q

skeletal muscle shivering is stimulated by

A

direct motor response from posterior hypothalamus

32
Q

Long term efferent control of temp

A

Endocrine system

33
Q

Short term efferent control of temp

A

Neurologic control via ANS

34
Q

Endocrine control of temp

A

ACTH, GH, ADH, TSH

35
Q

Physiologic response to hyperthermia

A

inhibition of heat production, increase heat dissipation

36
Q

most important mechanism for transferring heat between core/periphery

A

cutaneous vasodilation

37
Q

major mechanism for evaporative heat loss

A

diaphoresis

*via sympathetic cholinergic fibers

38
Q

body responds to hypothermia via

A

increasing heat production, decreasing heat loss

39
Q

Body not capable of countering heat loss at what temp

A

32-33*C

40
Q

Body decrease by 1*C results in

A

6% reduction in metabolism
8% reduction in O2 consumption
7% CBF/brain O2 consumption
7% MAC reduction