U3 Homeostasis: Thermoregulation Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Define thermoregulation

A

The balance of heat gain and loss to maintain a constant internal body temperature of around 37°C independent of the environmental temperature

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

Why does the body temperature need to remain constant at around 37°C?

A
  • It is the optimal temperature for cellular reactions and stable cell function
  • increased body temperature can cause nerve damage, structural change of proteins and death
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why is the human body usually maintained at a higher temperature than the external environment?

A

Because of heat produced as a result of metabolic activity

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

Why does exercise increase body temperature?

A

Exercise increases the metabolic rate and generates more heat than the body needs to keep its temperature constant

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

What are the two ways the body responds to deviations in temperature?

A

Behavioural:
- where we consciously change our behaviour

Physiological:
- where our body automatically changes its functioning without conscious control

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

How does heat gain/input occur?

A
  • Heat from metabolic processes in the body
  • Heat gained from surroundings by conduction and radiation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does heat loss/output occur?

A
  • Radiation, conduction and convection to surroundings
  • Evaporation of water from skin and lungs
  • Warn air breathed out
  • Warm urine and feces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define metabolic rate

A

The rate at which energy is released to the body by the breakdown of food

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

What increases the metabolic rate?

A
  • Exercise (muscular activity)
  • Stress (increased activities of autonomic nervous system)
  • Body temperature (increases rate of biochemical reactions)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define thermoreceptors

A

Receptors locate din the skin or hypothalamus that detect changes in temperature

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

What are the two types of thermoreceptors?

A

Peripheral thermoreceptors
- located in skin and some mucus membranes
- detect temperature changes in external environment
- sends information to hypothalamus

Central thermoreceptors
- located in hypothalamus
- detect the temperature of the internal environment

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

Distinguish between cold receptors and heat receptors

A

Cold receptors
- thermoreceptors stimulated by temperatures lower than normal
- when stimulated, the hypothalamus receives the information and initiates heat conservation and heat production mechanisms

Heat receptors
- thermoreceptors stimulated by temperatures higher than normal
- when stimulated, the hypothalamus receives the information and initiates heat production and heat loss mechanisms

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

What are the ways that body temperature is regulated?

A
  • Skin
  • Blood vessels
  • Sweating
  • Shivering
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why is the skin important in regulating body temperature?

A

The skin has a large surface area and its located between the internal and external environments

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

How can heat be lost/gained by the skin?

A

Conduction:
- transfer of heat by direct movement between particles

Convection:
- transfer of heat by movement of liquid or gas

Radiation:
- transfer of heat by infrared radiation emitted by objects

Evaporation:
- process of a liquid forming a gas, which absorbs heat energy

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

How do blood vessels regulate body temperature?

A
  • Blood vessels located in the dermis of the sin carry heat from the core of the body to the skin
  • The diameter of the surface arterioles is controlled by autonomic nerves

Vasodilation
- an increase in the diameter of the surface arterioles
- increases the blood flow through surface arterioles
- more blood is transported to the capillaries in the skin
- rate of heat loss increases

Vasoconstriction
- a decrease in the diameter of the surface arterioles
- decreases the blood flow through surface arterioles
- less blood is transported to the capillaries in the skin
- rate of heat loss decreases

17
Q

How does sweating regulate body temperature?

A
  • Occurs when body heat must be lost and surface blood vessels are at maximum dilation
  • Sweating: the active secretion of fluid by the sweat glands to the skin surface
  • Evaporation of sweat from the skin surface has a cooling effect as the heat is removed from the skin when liquid sweat change into vapour
  • Cooling of the skin results in the cooling of the blood flowing through the skin
18
Q

How does shivering regulate body temperature?

A
  • Shivering: rhythmic muscle tremors that increase body heat production
  • As no work is being done, heat produced by the muscles is released as heat
19
Q

What occurs to decrease heat loss in cold conditions?

A
  • Vasoconstriction of blood vessels in the skin
  • Decreased sweating
  • Conscious behaviour: putting on a jumper, curling into a ball
20
Q

What occurs to increase heat production in cold conditions?

A
  • Increased shivering
  • Increased metabolic rate
  • Increased voluntary physical activity
21
Q

What occurs to increase heat loss in hot conditions?

A
  • Vasodilation of blood vessels in the skin
  • Increased sweating
  • Conscious behaviour: removing clothes, turning on a fan
22
Q

What occurs to decrease heat production in hot conditions?

A
  • Decreased metabolic rate
  • Decreased voluntary physical activity
23
Q

Distinguish between heat exhaustion and heat stroke (4 dot points each)

A

Heat exhaustion
- Occurs in high temperature and normal humidity
- Involves increased sweating, evaporation and cooling
- There is no change in core body temperature
- Is not fatal

Heat stroke
- Occurs in high temperature and high humidity
- Involves increased sweating, but no evaporation and therefore no cooling
- The core body temperature increases
- Can be fatal

24
Q

Hypothermia

A
  • Occurs when a person’s core body temperature falls below 33°C
  • The metabolic rate is decreased
  • The amount of heat the body produced is decreased
  • There is greater heat loss to the environment than heat gain