Skin And Temperature Control

Question 1

What does homeothermic mean

Answer 1

Tightly regulated body temp. (E.g. humans)

Question 2

What is normal core body temperature, what happens this is above 41/below 30

Answer 2

Normal = 37 +/- 0.5 Celsius
Above 41 = proteins start to denature
Below 30 = lose consciousness

Question 3

Why may body temperature vary (4)

Answer 3

External temp
Activity
Circadian rhythm (drops overnight)
Menstrual cycle

Question 4

Where are peripheral thermoreceptors located

Answer 4

Located in the skin (especially in face, scrotum)

Question 5

Where are central thermoreceptors located

Answer 5

Spinal cord, abdominal organs, hypothalamus

Question 6

What do peripheral thermoreceptors detect

Answer 6

Change in environmental temperature

Question 7

What do central thermoreceptors detect

Answer 7

Change in core body temperature

Question 8

How is heat generated within the body (4)

Answer 8

General metabolism
Voluntary muscular activity (e.g. moving around)
Shivering thermogenesis (involuntary muscular activity)
Non-shivering thermogenesis (only significant in infants due to brown adipose tissue)

Question 9

What is the response to cold stress (2)

Answer 9

Vasomotor control: sympathetic arteriolar constriction reduces delivery of blood to skin

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

Question 10

How cold does deep body temperature have to get for hypothermia

Answer 10

35 Celsius

Question 11

How is heat production minimised in response to heat stress (2)

Answer 11

Decrease metabolic rate:
- Decreased physical activity
- Decreased food intake

Question 12

How is heat loss from the body increased (3)

Answer 12

Vasomotor control (arteriolar dilation increases delivery of blood to the skin)
Sweating (sympathetic cholinergic fibres increase evaporative heat loss)
Behavioural responses (removing clothing, move to shaded area, increasing surface area)

Question 13

Why do we get fevers

Answer 13

Part of the bodies mechanism for fighting infection

Question 14

What causes fevers

Answer 14

Caused by endogenous pyrogens
Endogenous pyrogens increase the set point controlled by the hypothalamus (set point increased above core body temp hence why you feel cold and shivery —> body responds to try and reach set point)

Question 15

How do endogenous pyrogens increase the set point, why then do paracetamol and aspirin reduce fever

Answer 15

Caused by local production of prostaglandins by cyclo-oxygenate in the hypothalamus

Paracetamol and aspirin inhibit cyclo-oxygenases = anti-pyretics (reduce fever)