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Physiology Exam 2 Endocrine (Shelby) > Temperature Regulation > Flashcards

Flashcards in Temperature Regulation Deck (63)
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1
Q

What does thyroid hormone do for temperature regulation?

A
  1. stimulates Na+-K+ ATPase
  2. increase O2 consumption
  3. increased metabolic rate
  4. increases vasodilation
2
Q

two things the anterior (rostral) hypothalamus stimulates to increase heat loss

A
  1. vasodilation in skin

2. sweat

3
Q

process in which energy (heat) travels through a medium or space

A

radiation

4
Q

Leptin requires synergistic action of ______ to increase body temperature

A

thyroid hormone

5
Q

Cytokines cause the release of ______ in the OVLT of the hypothalamus where the BBB is absent

A

prostaglandins

6
Q

skin blood perfusion can vary between _______ mL/min

A

400-2500

7
Q

the rate of heat loss in convection depends on the

A

rate of fluid movement

8
Q

compensatory adjustment in _________ must be made to maintain thermal balance

A

thermal flux

9
Q

How does excessive catecholamine increase body temperature?

A

stimulation of a-1 receptors in vascular smooth muscle —-> reduces blood flow to the surface of the skin (heat is trapped)

10
Q

_____ hypothalamus stimulates heat dissipation (parasymp)

A

anterior (rostral)

11
Q

You are super hot and your body has vasodilated to try to increase heat loss, but you are also hypotensive. Which one will take precedence, the heat crisis or the hypotensive crisis?

A

temperature control will always take precedence

12
Q

the transfer of thermal energy through solid matter

A

conduction

13
Q

Why do you shiver with a fever

A

peripheral vasoconstriction shuts blood supply to the skin down to increase core temperature, and this is perceived as cooling of the skin even in a warm room

14
Q

What happens with heat acclimation? (5 things)

A
  1. lower heart rate
  2. lower threshold for cutaneous vasodilation
  3. better control of core temp
  4. increased plasma volume
  5. increased sweat
15
Q

Why are you at more risk for heat stroke when you are dehydrated?

A

reduced ability to perspire

16
Q

hypothermia induced impairment of temperature regulation- unable to self regulate (like shivering) temperature range

A

30-34 C

(86-93.2) F

17
Q

Eccrine glands are innervated by the ______ and use _____

A

sympathetic nervous system

acetylcholine

18
Q

sweating is less effective as air becomes:

A

saturated with water vapor

more humid!

19
Q

two things the posterior (caudal) hypothalamus stimulates in relation to heat conservation

A
  1. skin vasoconstriction

2. postural changes

20
Q

Cold receptors respond to a range of cool temperature _________

A

24-28 C

21
Q

The mechanism for heat loss from the skin surface is usually a combination of:

A

radiation + convection + evaporation

22
Q

during conditions of low physical activity, how is most of the heat lost from the body?

A

radiation

23
Q

In the dry Phoenix air, how much sweat can be evaporated from the skin/resp. tract in an hour?

A

2-3 liters

24
Q

rate of heat transfer between a body and moving air is __________ than the rate between a body and moving water

A

lower

25
Q

Why is sweat rate greater in trained individuals

A

skin blood perfusion is greater

26
Q

which is cooler?

cool clothing or naked

A

cool clothing

27
Q

How does aspirin help lower fever

A

cox inhibitor
decreased prostaglandins
decreased hypothalamic set point

28
Q

the majority of passive heat transfer from core to skin is by:

A

convection in the vascular circulation

*some conductance

29
Q

four things the posterior (caudal) hypothalamus stimulates in relation to heat production

A
  1. shiver
  2. increased muscle tone
  3. increased voluntary actions
  4. stimulation of brown fat
30
Q

which form of temperature regulation is most important to unload the heat generated by intense activity if the humidity is HIGH

A

convection

which sucks

31
Q

hypothermia induced cardiac fibrillation temperature range

A

27-29 C

(80.6-84.2) F

32
Q

eccrine glands:

apocrine glands:

A

eccrine glands: everywhere, clear odorless

apocrine glands: axial/genital, thick with odor

33
Q

What do prostaglandins due during an infection

A

stimulate preoptic area of the hypothalamus (POA) to determine the hypothalamic set point

integrated heat production increases body temperature

34
Q

vasoconstriction (increases/decreases) convective heat transfer

A

decreases

35
Q

heat moves _____ its thermal gradient

A

down

36
Q

What integrates thermal information?

A

preoptic area of the hypothalamus (POA)

37
Q

Infection causes the release of endogenous pyrogens (cytokines) from:

A

macrophages

38
Q

The preoptic area of the hypothalamus (POA) is sensitive to temperature changes as small as

A

0.01 C

39
Q

water vaporizing from respiratory passages and the surface of the skin

A

evaporation

40
Q

which form of temperature regulation can unload most of the heat generated by intense activity if the humidity is low

A

evaporation

convection is second

41
Q

hyperthermia (from fever of exercise) temperature range

A

38-40 C

(100.4-104) F

42
Q

How many calories will evaporate 1 g of H2O

A

580

43
Q

two things the anterior (rostral) hypothalamus stimulates to decrease heat production

A
  1. decreased muscle tone

2. decreased voluntary actions

44
Q

Heat inputs to the body can come from:

Heat outputs from the body are:

A

internal and external

external environment ONLY

45
Q

What is the role of peripheral thermoreceptors?

Where do the send information?

A

anticipate changes before they affect the core temperature

centreal thermoreceptors in the preoptic area of the hypothalamus (POA)

46
Q

A spike in basal body temperature would indicated:

A

ovulation

47
Q

Leptin signaling in the preoptic area of the hypothalamus (POA) influences temperature-sensitive neurons to ______ body temperature

How

A

increase

stimulation of B-receptors in brown fat, activating decoupling enzyme

48
Q

normal body temp range

A

36-38 C

(96.8-100.4) F

49
Q

the process of losing heat through movement of air or water molecules across the skin

A

convection

50
Q

infection causes macrophages to release:

A

endogenous pyrogens (cytokines)

51
Q

How does thyroid hormone effect brown fat? (BAT)

A

brown fat has abundant type-2 deiodinase to facilitate T3 signaling

brown fat = heat production

works well for infants in temperature changes

52
Q

heat stroke, multiple organ failure, brain lesions temperature range

A

40-44 C

(104-111) F

53
Q

______ hypothalamus stimulates heat production and conservation (sympathetic)

A

posterior (caudal)

54
Q

a lower basal metabolic rate would be a (larger/smaller) range of thermoneutral zone

A

larger

55
Q

Basal body temp during follicular phase: (lower/higher)

A

lower

56
Q

mild hypothermia (cold and shivering) temperature range

A

34-36 C

(93.2 - 96.8) F

57
Q

vasodilation (increases/decreases) convective heat transfer

A

increases

58
Q

Which two temperature regulating mechanisms compensate for increased heat production during exercise?

A

evaporative

convective

59
Q

radiative emission from the body is via ______

A

infrared photons

60
Q

Where do cytokines enter the hypothalamus during infection

A

OVAT (where the BBB is absent)

61
Q

excessive thyroid hormone will _____ body temperature

A

increase

62
Q

warmth receptors are sensitive to a narrow range of hot temperature _________

A

44-46 C

63
Q

Basal body temp during luteal phase (Lower/higher)

A

higher