skin and temperature control

Question 1

What is the normal body temperature

Answer 1

37 plus or minus 0.5 degrees

Question 2

What do warm temperature receptors do in response to warm temperature

Answer 2

Warm receptors Increase in frequency

Cold receptors decrease in frequency

Question 3

What do cold receptors do in response to temperature drop

Answer 3

Cold receptors Increase in frequency

Warm receptors - decrease in frequency

Question 4

Where are peripheral thermoreceptors located

Answer 4

Skin - especially face and scrotum

Question 5

Where are central thermoreceptors located

Answer 5

hypothalamus, spinal cord and abdominal organs

Question 6

What do peripheral thermoreceptors respond to

Answer 6

Change in environmental temperature

Question 7

What do central thermoreceptors respond to

Answer 7

Change in core body temperature

Question 8

What generates heat in the body

Answer 8

Increased metabolism

futile muscular activity - muscles produce heat when doing activity

Shivering thermogenesis - involuntary muscle movement

non-shivering thermogenesis - mainly occurs in infants

Question 9

Why does non-shivering thermogenesis mainly occur in infants

Answer 9

Because it occurs in brown fat

Question 10

What reduces heat loss from the body

Answer 10

Sympathetic arterial constriction which limits the blood being delivered to the periphery

Behavioural responses - adding clothes, reducing surface area and moving to warmer areas

Question 11

What is hypothermia

Answer 11

Core body temperature dropping below 35 degrees

Question 12

Who is most at risk of hypothermia

Answer 12

Neonates - not much fat but have brown fat so they can do non shivering thermogenesis - They also have large surface area so they lose more heat

Elderly

Homeless people

Question 13

What is the treatment for cold stress

Answer 13

Insulation to prevent further heat loss

Slow re-warming blankets

Internal reheating with warm drinks or hot air

Immersing the body in warm water

Extracorpeal circulation - taking blood out of the body, warming it up, and then putting it back into the body

Question 14

What are the consequences of cold stress

Answer 14

Frost bite

Vasoconstriction to prevent heat loss which promotes thrombosis and causes anoxia

Ice crystals can form in extracellular space which causes water to try equiblirate and follow the crystal which dehydrates cells

Question 15

What is frostbite

Answer 15

vasoconstriction and increased viscosity as a response to cold temperatures which causes anoxia and leads to cell death

Question 16

how does cold temperature increase risk of myocardial infarction

Answer 16

Cold temperatures cause vasoconstriction and increase viscosity which increases the afterload on the heart so the heart has to work harder to pump blood around the body and this increases risk of MI

Question 17

What reduces heat production

Answer 17

Decreased physical activity and food intake

Question 18

What increases heat loss from the body

Answer 18

Vasodilation which increases blood delivery to the skin

Sweating - increases heat loss via evaporation

Behavioural responses - taking off clothes

Question 19

What causes sweating

Answer 19

Sympathetic cholinergic fibres

Question 20

What is heat exhaustion

Answer 20

Body temp 37.5-40 degrees

Results in vasodilation and drop in central blood volume due to excess sweating which also cayuses issues with the fluid salt balance

Question 21

What are the symptoms of heat exhaustion

Answer 21

Headache
confusion
nausea
profuse sweating
clammy skin
tachycardia
hypotension
weak pulse
fainting

Question 22

What is heat stroke and its main symptom

Answer 22

Body temp above 40

Failure of body temperature control

Symptoms - hot dry skin due to no sweating and circulatory response

Question 23

Who are the most at risk for heat and cold stress

Answer 23

neonates and elderly

Question 24

What is the treatment for heat stress

Answer 24

Move to cool environment
remove clothing
fan
sponge with tepid water - not too cold or hot
Give fluids - oral or IV

Question 25

What causes fever and why do fevers occur

Answer 25

Pyrogens

Fevers occur to fight off infections

Question 26

how do pyrogens produce a fever

Answer 26

Cause production of prostaglandins by cyclo-oxygenase in the hypothalamus

Question 27

Why are aspirin and paracetamol antipyretics

Answer 27

They inhibit cyclo-oxygenase so the set temperature cannot be increased