Temperature Homeostasis

Question 1

What is homeostasis?

Answer 1

Maintenance of internal body conditions within a narrow range of values – a “steady state”, so that organs and systems can continue to function.

Question 2

What are homeostatic mechanisms?

Answer 2

Are the mechanisms that maintain internal conditions they allow some independence from external environment and therefore a survival advantage

Question 3

What do the terms steady-state and dynamic equilibrium mean?

Answer 3

A balanced internal environment in terms of Body temp, pH and concentration of dissolved substances, Glucose concentration, O2 and CO2 concentration.

Question 4

What are the tolerance limits?

Answer 4

The upper and lower limits of the factors in the body
Normal function within tolerance limits

Question 5

What are the 5 parts of a feedback loop?

Answer 5

Stimulus
Receptor
Modulator
Effector
Response
Feedback (* extra)

Question 6

What is the body’s set point temperature?

Answer 6

37 degrees.

Question 7

Provide 2 issues of the body under high and low temperature

Answer 7

High:
- Denature of proteins
- Chemical reactions are uncontrolled
Low:
- Slower cellular reactions
- Death

Question 8

What are some methods of external heat gain and external heat loss?

Answer 8

Heat Gain:
- Warm air from the heater
- Warm water in a bath
- Warm air outside from the sun
Radiation: Solar Radiation when standing in the sun. Radiation from a heater.

Heat Loss:
- Cold air outside or in a cold room
- Cold wind moves heat very quickly away from skin
- Cold water in a bath

Question 9

What are some methods of internal heat gain?

Answer 9

Via cellular respiration (metabolism)
During exercise

Question 10

What are peripheral thermoreceptors?

Answer 10

In skin and other surface tissues
Detect temperature of external environment
Cold receptors
Heat receptors
Send signals to hypothalamus, which then acts to regulate body temperature

Question 11

What are central thermoreceptors?

Answer 11

In hypothalamus, spinal cord, abdominal organs
Send signals to hypothalamus, which then acts to regulate body temperature

Question 12

What are the 2 main control centres for thermoregulation?

Answer 12

Hypothalamus
Cerebral Cortex

Question 13

Present all 6 steps of the feedback loop for when body temperature falls below set point. [not conscious effectors]

Answer 13

Stimulus: Body temperature has fallen below 37 degrees.

Receptors: Central thermoreceptors in the hypothalamus and Peripheral thermoreceptors in skin

Modulator: The hypothalamus

Effectors:
- Blood Vessels
- Adrenal Medulla
- Brain Centres for muscle tone
- Thyroid

Response:
Blood vessels constrict to reduce blood flow, and reducing heat exchange
Adrenal medulla release adrenaline to increase metabolic rate
Skeletal Muscles shiver to produce heat via kinetic energy
Thyroid increase more T4 (Thyroxine) to increase metabolism and release heat as a byproduct.

Question 14

List the effectors of thermoregulation

Answer 14

• Blood Vessels
• Sweat Glands
• Skin