Thermoregulation and pyrexia L8 Flashcards

1
Q

at what temp does denaturing occur

A

above 45 degrees

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2
Q

range of temps where there is conscious intelligence

A

35-40 degrees

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3
Q

when in the day are you coolest

A

just before you wake up

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4
Q

when in the day are you hottest

A

mid afternoon

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5
Q

rise in temperature in the menstrual cycle

A

0.5 degrees at ovulation

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6
Q

what fibres transmit temperature

A

A delta and C fibres (same as pain)

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7
Q

coordinator of thermoregulation

A

anterior hypothalamus

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8
Q

do we have more hot or cold receptors

A

more cold receptors (we are a cold species)

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9
Q

normal body temp=

A

37.5 degrees

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10
Q

heat production=

A

metabolism

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11
Q

what type of response is most important to maintain temperature

A

voluntary actions

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12
Q

e.g of voluntary actions

A

wearing a coat

wearing less clothing in the sun

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13
Q

what disadvantage do the very old and very young have

A

often can’t put clothing on themselves

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14
Q

5 changes when too cold

A
shivering 
brown fat 
skin blood flow
piloerection 
neuroendocrine
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15
Q

how much can shivering increase heat production

A

5%

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16
Q

what body movement is shivering predominately

A

truncal

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17
Q

disadvantage of shivering

A

metabolically expensive

can lose vital energy

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18
Q

who has brown fat

A

neonates and animals

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19
Q

what is brown fat (3)

A
  • adipose tissue with lots of mitochondria
  • higher blood supply than normal fat
  • Beta 3 receptors
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20
Q

what does brown fat do

A

burns fat into energy

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21
Q

2 changes in skin blood flow

A

vasodilation

vasoconstriction

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22
Q

how much can skin blood flow alter heat loss

A

8%

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23
Q

what happens to skin blood flow in prolonged cold exposure

A

paradoxical increased flow

24
Q

what Nervous system mediates skin blood flow

A

sympathetic

25
Q

piloerection=

A

hairs stand on end

26
Q

erector pili under what control

A

sympathetic

27
Q

effect of erector pili

A

minimal effect in humans

28
Q

what neuroendocrine effect happens when you’re cold

A

increased catecholamines (adrenaline/ noradrenaline)

29
Q

heat loss by conduction/convection=

A

60%

30
Q

heat loss by radiation=

A

25%

31
Q

heat loss by evaporation

A

15%

32
Q

what system controls sweat glands

A

sympathetic

33
Q

most neurotransmitters of sympathetic=

A

noradrenaline

34
Q

whats different about the neurotransmitters in sweat glands

A

cholinergic (muscarinic)

35
Q

3 substances filtered across in sweat

A

sodium
chloride
urea

36
Q

what is sweat like in people who have acclimatised to heat

A

sweat more but more concentrated so lose less sodium

37
Q

how much does heat loss increase by sweat

A

10x

38
Q

2 abnormalities in thermoregulation

A

hypothermia

hyperthermia

39
Q

hypothermia=

A

core temp <35 degrees

40
Q

severe hypothermia=

A

<28 degrees

41
Q

3 causes of hypothermia

A

behavioural
hypothyroidism
dermatological

42
Q

3 clinical features of hypothermia

A

confusion
coma
cardiovascular

43
Q

common cardio complication of hypothermia

A

atrial fibrillation

44
Q

what is not advised when someone is hypothermic

A

defibrillation

45
Q

management of hypothermia

A

ABC; airways, breathing , circulation

-controlled warming (via warming blankets

46
Q

what can be used for extreme hypothermia in big hospitals

A

bypass

47
Q

hyperthermia=

A

> 38 degrees

48
Q

life threatening hyperthermia=

A

> 40 degrees

49
Q

4 causes of hyperthermia

A

exertion (exercise)
situational (heat stroke)
Drugs
pyrexia

50
Q

4 clinical signs of hyperthermia

A

confusion
seizures
coma
cardiovascular

51
Q

what is pyrexia usually due to

A

altered set point

52
Q

causes of pyrexia (5)

A
  • infection
  • blood transfusion
  • inflammation
  • malignancy
  • hypothalamic insult
53
Q

what in the body is a major contributor to pyrexia (drug target)

A

prostaglandins

54
Q

drugs that treat pyrexia

A

NSAID
Aspirin
paracetamol

55
Q

why do we get a fever

A

to get rid of pathogens

56
Q

when is a fever bad

A

head injury

post cardiac arrest

57
Q

why do we treat fever

A

to make people feel better