Skin and Temperature Regulation

Question 1

What is normal body temperature?

Answer 1

37 +/- 0.5C

Question 2

At what temperature do proteins start to denature?

Answer 2

Above 41C

Question 3

Below what temperature do you lose consciousness?

Answer 3

30C

Question 4

What does temperature vary with?

Answer 4

External temperature
Activity
Circadian rhythm
Menstrual cycle

Question 5

What is core temperature maintained by?

Answer 5

Balancing heat loss and heat gain

Question 6

On a brisk walk, how much would the temperature raise by per 10 minutes?

Answer 6

1C

Question 7

What is conduction?

Answer 7

Heat transfer directly between touching objects

Usually a source of heat loss but can be heat gain as well

Question 8

What is convection?

Answer 8

Fluid conduction hence wind chill and water chill

Question 9

What is lost via evaporation?

Answer 9

Respiration and sweating

Question 10

How much fluid is lost from evaporation during the day at rest?

Answer 10

600 ml per day

Question 11

What is the biggest source of heat loss from the skin?

Answer 11

Radiation

Question 12

What is the cold receptors of the skins peak firing rate?

Answer 12

Below 30C

Question 13

What is the range the cold receptors fire in?

Answer 13

10 - 40C

Question 14

What is the peak firing rate for warm receptors?

Answer 14

Above 40C

Question 15

What do the warm receptors fire in the range of?

Answer 15

30 - 50C

Question 16

Where are peripheral thermoreceptors located?

Answer 16

Skin
especially in
- face
- scrotum

Question 17

Where are central thermoreceptors located?

Answer 17

Spinal cord
Abdominal organs
Hypothalamus

Question 18

What does the peripheral thermoreceptors detect?

Answer 18

A change in environmental temperature

Question 19

What do the central thermoreceptors detect?

Answer 19

A change in body temperature

Question 20

Where do changes detected by both of the receptors go?

Answer 20

To the hypothalamic thermoregulatory centre

Question 21

What responses does the body have to cold stress?

Answer 21

General metabolism
Voluntary muscular activity
Shivering thermogenesis (involuntary)
Non shivering thermogenesis (only significant in infants due to brown adipose tissue)

Question 22

What is heat loss from the body reduced by?

Answer 22

Vasomotor control
- sympathetic arteriolar constriction reduces the delivery of blood flow to the skin 
Behavioural responses
- reducing surface area
- adding clothing
- moving to warmer environment

Question 23

Definition of hypothermia

Answer 23

A fall in deep body temperature to below 35C

Question 24

Who is at risk of cold stress?

Answer 24

Neonates
Elderly 
Vagrants
Cold store workers
North sea workers
Outdoor pursuits

Question 25

Treatment for cold stress

Answer 25

Dry / insulate to prevent further heat loss Slow rewarming with bag/blanket Intermetal rewarming with hot drinks and/or warm air

Question 26

Pathology of frost bite

Answer 26

Vasoconstriction increase in viscosity of blood so harder to push through Promotes thrombosis Causes anoxia Ice crystals form in extracellular space Increases extracellular osmolarity Causes movement of water from intracellular space Cell dehydration and death

Question 27

What is the excess mortality in the winter?

Answer 27

40%

Question 28

How is heat production minimised?

Answer 28

Decreased physical activity | Decreased food intake

Question 29

Heat loss from the body is increased by...….

Answer 29

``` Vasomotor control - arteriolar dilation increases delivery of blood to the skin Sweating - sympathetic cholinergic fibres increase evaporate heat loss Behavioural responses - increasing surface area - remove clothing - move to shaded area/colder environment ```

Question 30

Definition of heat exhaustion

Answer 30

Body temperature raised in range 37.5-40C

Question 31

Another name for heat exhaustion

Answer 31

Heat illness

Question 32

Pathology of heat exhaustion

Answer 32

Vasodilation and drop in central blood volume | Caused by disturbance of the bodys fluid/salt balance due to excess sweating

Question 33

Presentation of heat exhaustion

Answer 33

``` Headache Confusion Nausea Profuse sweating Clammy skin Tachycardia Hypotension Weak pulse Fainting Collapse ```

Question 34

What can heat exhaustion lead to?

Answer 34

Heat stroke

Question 35

What is another name for heat stroke?

Answer 35

Heat injury

Question 36

Definition of heat stroke?

Answer 36

Body temp raised above 40C

Question 37

Pathology of heat stroke

Answer 37

Body temp control mechanisms fail

Question 38

Presentation of heat stroke

Answer 38

Hot dry skin (sweating ceased) | Circulatory collapse

Question 39

Who are those most at risk of overheating?

Answer 39

Neonates Elderly People doing physical work in hot humid environments Workers wearing non breathable protective clothing

Question 40

Why is humid environments not ideal to cool your body down?

Answer 40

You cannot get rid of heat using evaporation in humid environments

Question 41

Treatment of heat stress

Answer 41

``` Move to cool environment Remove clothing Fan Sponge with tepid water Give fluids - oral - IV ```

Question 42

What is fever a mechanism of?

Answer 42

Fighting infetion

Question 43

Cause of fever

Answer 43

Endogenous pyrogens IL-1 and IL-6