Physiology 7: Body temp Flashcards

1
Q

What happens if body temp is too low?

A

Too low
- Slow metabolism
Inadequate O2 supply (molecules have less kinetic energy, lower O2 affinity)
Freezing of cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens if body temp is too high?

A

Too high
Proteins denature
Inadequate O2 supply (metabolic rate increases, tissue O2 requirement increases)
Membrane structure alterations
= geographical ranges of animals would be restricted to temp favourable regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 4 heat exchange processes?

A

Radiation
Convection
Conduction
Evaporation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe radiation

A

Without direct contact
In humans, 60% heat loss
E.g from the sun

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe convection

A

Air/fluid across body surface
15% heat loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe conduction

A

With direct contact
In humans, 3% heat loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe evaporation

A

Water from body surface
22% heat loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How to minimise heat loss through radiation in a cold environ

A

Decreasing SA:V
Layers of clothing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How to minimise heat loss through convection in a cold environ

A

Layers of clothing
Sheltered from wind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How to minimise heat loss through evaporation in a cold environ

A

Little exposed skin
Dry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How to minimise heat loss through respiration in a cold environ

A

Cover mouth and nose, stops cold air from entering lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

larger animals have ______ SA:V so lose heat less quickly

A

smaller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe ectotherms

A

Body temp fluctuates with environ
Temp conformers
Heat is derived from environ
E.g reptiles, amphibians

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are ectotherms also known as

A

poikilotherms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give an example of an ecotherm

A

Reptiles, amphibians

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe endotherms

A

Constant body temp
Regulators
Heat derived from metabolism

17
Q

What are endotherms also known as

A

homeotherms

18
Q

Give an example of an endotherm

A

humans

19
Q

What are the benefits for ectotherms?

A

Metabolic rate is 5x slower than endo
Less energy = less food = less h20
Can devote large proportion of energy budget to reproduction
Good colonisers of poor arid environs

20
Q

What are the disadvantages for ectotherms?

A

No nocturnal environ niches (unless in tropical and summer temperate areas)
Cannot sustain high activity bursts as risks O2 debt
Anaerobic = lactate accumulation = fatigue
*

21
Q

What are the benefits for endotherms?

A

Can sustain high activity burst
Nocturnal activity
Able to exploit cooler environs
Forage widely and migrate over long distances

22
Q

What are the disadvantages for endotherms?

A

Require larger body sixes with lower SA:V
Metabolic rate 5x faster than ecto
*

23
Q

What are the 3 mechanisms for insulation?

A

Brown fat
Blubber
Fur/hair/feathers

24
Q

Describe brown fat

A

Brown fat (adipose tissue)
Specialised for rapid heat production

25
Q

Describe blubber

A

Thick vascularized adipose tissue under skin of sea mammals
Low thermal conductivity of skin, low metabolic activity

26
Q

What is the function of fur/hair/feathers

A

Reduces convection by trapping layer of warm air close to skin surface
Effect is lost if air is replaced by water

27
Q

Describe countercurrent heat exchanges

A

Blood in hot artery flows by colder veins and exchanges heat, so cold blood does not return to the heart

28
Q

Where are countercurrent heat exchanges found?

A

birds, tongues of whales, dolphins fins

29
Q

Describe the thermal neutral zone

A

→ above upper critical limit, body must expend energy to decrease body temp
→ lower critical ***
Hypothalamus = control centre for this

30
Q

What are the thermoregulatory processes below the lower critical limit?

A

Vasoconstriction
Shivering
Hormones
Brown adipose tissue

31
Q

Describe vasoconstriction

A

Diameter of blood vessels decreases
Blood flow to skin decreases
Skin cools
Less heat loss to environ through radiation, conduction and convection
Heat trapped in body core

32
Q

What is shivering?

A

Rapid contriction of skeletal muscles

33
Q

What are the hormones involved in the thermoregulatory processes below the lower critical limit?

A

Adrenaline
Thyroxine

34
Q

Describe how the brown adipose tissue is involved in the thermoregulatory processes below the lower critical limit

A

Rich in mitochondria = breakdown fuel into heat only
Usually broken down into energy and heat
Rich blood supply
Found in newborn mammals, hibernating mammals and the necks of human adults
Non-shivering thermogenesis

35
Q

What are the thermoregulatory processes below the upper critical limit?

A

Vasodilation
Perspiration
Panting

36
Q

Describe vasodilation

A

Diameter increases
Blood flow to skin increases
Skin heats up
***

37
Q

Describe hypothermia

A

if metabolic heat production cannot compensate for heat loss

38
Q

Describe hyperthermia

A

if evaporative cooling cannot counteract heat gain