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Flashcards in Skin + Temperature Deck (36)
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1

What is core body temp

37 degrees +- 0.5

2

Why is this important

>41 = proteins denature
<30 = LOC

3

What does body temp vary with

External temp
Activity
Circadian rhythm
Menstrual cycle

4

What do we produce all the time

Heat

5

How do you we manage heat

Conduction - heat transfer between touching
Convection - fluid conduction e.g. wind / water chill
Evaporation - respiration / sweating taking heat energy with it (main loss in body)
Radiation - can be loss or gain

6

What do cold receptors do

Respond to cold temp
Peak fire at 30 degrees (10-40 range)

7

What do warm receptors do

Respond to warm temp
Peak fire at 40 degrees (30-50)

8

How do you tell apart

Dynamic response to change in temp
Warm receptors fire more when temp increases

9

What are peripheral thermoreceptors

Located in the skin
Face and scrotum sensitive
Respond to environmental temp

10

What are central thermoreceptors

Located in spinal cord, abdominal organs and hypothalamus
Tell core temperature

11

What happens

Nerves go to hypothalamic thermoregular centre
Response generated

12

What nerve fibres detect cold

A delta

13

What nerve fibres detect warm

C fibres

14

What is fever

Body's response to infection

15

What causes fever

Endogenous pyrogenes (IL) Increase set point on hypothalamus of where body temp should be by producing prostaglandins
So feel cold when temp increases to this point

16

What helps fever

NSAID + Aspirin
Block cycle-oxygenase which stops prostaglandin production which turns up set point

17

How are prostaglandins produced

Cyclo-oxygenase in hypothalamus

18

How does body generate heat in cold stress

Cell metabolism
Voluntary muscle activity
Shivering thermogenesis - involuntary
Non-shivering thermogenesis in infants

19

What is nonshinvering thermogenesis

Brown adipose tissue
Uses protein gradient to produce heat

20

How is heat loss reduced in cold stress

Sympathetic arteriolar construction - A1
Behaviour - add clothes, move to warmth, reduce SA

21

What is hypothermia

<35 degrees

22

Who is at risk

Neonates
Elderly
Outdoor workers/ North Sea

23

How are neonates at risk

Big SA to volume
Little fat
Don't shiver

24

How are elderly at risk

Do not detect temp well
Immobile
Less shivering capacity

25

What does cold stress do to vascularity

Vasoconstriction so slow flow
Increased viscosity
Increased thrombosis
Hypoxia

26

What does cold stress to cellular

Ice crystals in extra-cellular space
Increased osmotic conc
Movement of water from intracellular space
Cell dehydration

27

What are complications

Increased heart attack and stroke due to vasoconstriction and viscosity

28

How do you Rx hypothermia

Dry + insulate to prevent further loss
Slow re-warming
Internal rewarming with hot drinks
Fast re-warming by immersion in water
Extra-corporeal circulation

29

How is heat production minister

Decreased physical activity
Decreased food intake

30

How is heat loss increased

Arteriolar dilation
Sweating
Increase SA
Remove clothes