6B: Regulation of body temperature

Question 1

What are 4 types of heat transfer?

Answer 1

Conduction
Convection
Evaporation
Radiation

Question 2

Explain what thermoregulation is?

Answer 2

The homeostatic process of maintaining constant internal body temperature by using the stimulus-response model and negative feedback loop.

Question 3

Explain conduction with an example.

Answer 3

The physical contact to initiate heat transfer - such as touching a hot kettle will transfer heat to fingers.

Question 4

Explain convection with an example.

Answer 4

Heat transfer via the movement of liquid or gas - such as temperature is warmer upstairs, because hot air rises and takes heat energy with it.

Question 5

Explain evaporation with an example.

Answer 5

The loss of heat via the conversion of liquid water to gas form - such as when sweating, the sweat on skin evaporates, taking heat energy with it.

Question 6

Explain radiation with an example.

Answer 6

The transfer of heat by electromagnetic waves (light) - such as the sun warming you via radiation.

Question 7

What are the effectors and their responses for when there is an increase in internal body and/or environmental temperature?

Answer 7

Sweat glands -> Sweating
Small blood vessels in skin -> dilation of arterioles
Cerebral cortex -> behaviour change
Arrector pili muscles -> flattening of hair
Cells -> decrease in metabolic rate

Question 8

What are the effectors and their responses for when there is a decrease in internal body and/or environmental temperature?

Answer 8

Skeletal muscle cells -> shivering
Small blood vessels in skin -> constriction of arterioles
Cerebral cortex -> behaviour change
Cells -> Increase in metabolic rate
Arrector pili muscles -> lifting of hair
Brown fat -> burning of triglycerides

Question 9

What is metabolic rate?

Answer 9

The amount of energy expended by an organism over a specific period of time.

Question 10

How does sweating help regulate body temperature?

Answer 10

Sweat glands increase secretion of sweat - and when it evaporates, heat energy is taken with it, therefore cooling the body down.

Question 11

How does vasodilation help regulate body temperature?

Answer 11

Arterioles near skin surface dilate, increasing blood flow. This increases amount of heat that can be lost through radiation, and why you look pink and flushed

Question 12

How does hair flattening help regulate body temperature?

Answer 12

Arrector pili muscles under skin relax, therefore causing hair to fall flat. This means less air is trapped by small hair on skin (making us colder as air is a good insulator).

Question 13

How does shivering help regulate body temperature?

Answer 13

Skeletal muscles contract in spasms, therefore increasing the respiration in the muscles. Heat is a by-product of respiration, therefore generating heat energy.

Question 14

How does vasoconstriction help regulate body temperature?

Answer 14

Arterioles constrict - limiting blood flow. This minimizes the amount of heat that can radiate from skin surface.

Question 15

How does lifting of hair help regulate body temperature?

Answer 15

Arrector pili muscles contract, causing hair to stand up. Hair traps a layer of air (good insulator), preventing heat loss.

Question 16

What is an endotherm?

Answer 16

Uses internally generated heat to maintain body temperature (by metabolism), and body temp stays steady regardless of environment. These include humans, mammals and birds.

Question 17

What is an ectotherm?

Answer 17

Depend mainly on external heat sources, and body temp changes with environmental temp. Exchange occurs via 4 heat transfer methods. Organisms include fish, reptiles and amphibians. They will find sunny/shady places that limit or maximize sun exposure.

Question 18

What is an exception to regulation of body temperature?

Answer 18

Fever: Body temp will increase to produce less suitable environment for bacteria/virus, and so immune system enzymes work better