Skin and Temperature Regulation

Question 1

What is the normal body temperature?

Answer 1

37 degrees

Question 2

AT what body temperature do proteins begin to denature?

Answer 2

41 degrees

Question 3

Below what temperature is consciousness lost?

Answer 3

30 degrees

Question 4

What four factors make up the thermal balance of the bosy?

Answer 4

Convection
Evaporation
Conduction
Radiation

Question 5

What is the normal heat production of the body at rest?

Answer 5

80kcal/hour

Question 6

What is the difference between convection and conduction?

Answer 6

They are essentially the same process except convection occurs when there is fluid contact with the body rather than solid objects

Question 7

How is body temperature detected?

Answer 7

Multiple receptor throughout the body are receptive to heat but some are exclusive to cold or heat

Question 8

What kind of receptors detect the extremes of temperature?

Answer 8

In effect, nociceptors

Question 9

As cold and warm receptors can overlap and fire over the same part of a their temperature range, how does the body know which stimulus is correct?

Answer 9

The receptors have dynamic responses as well as static ones which allow their firing to be differentiated

Question 10

Where are peripheral thermoreceptors concentrated?

Answer 10

In the skin, especially the face and scrotum

Question 11

Where are central thermoreceptors concentrated?

Answer 11

In the spinal cord, abdominal organs and hypothalamus

Question 12

What happens to the information coming in from the peripheral and central thermoreceptors?

Answer 12

They are relayed to the regulatory centre in the hypothalamus which analyses them and decides whether to change the body temperature

Question 13

What are four mechanisms which increase the heat levels within the body?

Answer 13

General metabolism - oxidative phosphorylation and other chemical reactions are not 100% efficient give off heat

Voluntary muscle activity

Shivering thermogenesis (involuntary)

Non shivering thermogenesis - in humans this is only significant in babies due to their levels of brown adipose tissue which are very low in adults

Question 14

What are two ways that heat loss from the body is reduced?

Answer 14

Vasomotor control - sympathetic arteriolar constriction in the periphery reduced delivery of blood to the skin and therefore reduces heat loss

Behavioural responses - reducing surface area, adding clothing, moving to warmer environment

Question 15

What is the definition of hypothermia?

Answer 15

A fall in body temperature to below 35 degrees

Question 16

Which groups of people are particularly at risk of hypothermia?

Answer 16

Neonates - do not detect temperature change well, not much fat, don’t shiver well
Elderly
Vagrants

Question 17

What is the treatment for hypothermia?

Answer 17

Dry/insulate to prevent further heat loss
Slow re-warming with bag/blankets
Internal re-warming with hot drinks and/or warm air
Fast re-warming by immersion in water - not recommended

Question 18

What are the vascular components of frost bite?

Answer 18

Vasoconstriction
Increase in viscosity
Promotes thrombosis
Causes anoxia

Question 19

What re the cellular components of frost bite?

Answer 19

Ice crystals form in the extracellular space, increasing osmolality and causing the movement of water from the cell and resulting in dehydration death

Question 20

What is the rate of excess mortality during winter in the UK?

Answer 20

40%

Question 21

What are three factors that increase heat loss from the body?

Answer 21

Vasomotor control - arteriolar dilation increases delivery of blood to the skin

Sweating - sympathetic cholinergic fibres increase increase evaporative heat loss

Behavioural responses - increasing surface area, removing clothing, moving to shaded area

Question 22

What is heat exhaustion? What are the effects? Is this heat illness or heat injury?

Answer 22

A body temperature raised in the range of 37.5-40
Causes vasodilation and a drop in central blood volume
Caused by a disturbance of the body’s fluid/salt balance due to excessive sweating
This is heat illness but may progress to injury

Question 23

What are the symptoms of heat exhaustion?

Answer 23

Headache
Confusion
Nausea
Profuse sweating
Clammy skin
Tachycardia
Hypotension
Weak pulse
Fainting & collapse

Question 24

What is heat stroke? Is this heat illness or injury?

Answer 24

A raise in body temperature above 40 degrees
This is heat injury, the control mechanisms have failed and the skin becomes hot and dry because sweating has ceased and circulatory collapse will occur

Question 25

Which groups of people are most at risk of heat illness and injury?

Answer 25

Neonates
Elderly
Physical labourers in hot climates

Question 26

What is the treatment for heat insult?

Answer 26

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

Question 27

Describe fever

Answer 27

Part of the bodies response to fighting infection

Caused by endogenous pyrogens

Question 28

What is the concept of the ‘set point’ with regard to the hypothalamus and fever?

Answer 28

When the body temperature rises as a result of exercise or environmental factors, the hypothalamic set point remains the same as the core temperature increases, allowing the increase to be detected and heat loss mechanisms to kick in
When the body is utilising fever to fight infection, the hypothalamic set point is raised, causing heat retaining and producing mechanisms to raise the core temperature, but because the set point has been raised, this is not corrected by the hypothalamus. Although this can be effective to aid with fighting infection, sever fever is dangerous and will eventually cause serious damage