Thermoregularion

Question 1

Using homeostatic mechanism, how does our body respond to heat?

Answer 1

Stimulus: increase body temperature
Sensor: receptors in skin detect high temp
Integrator: activates heat loss centre in hypothalamus
Effector: sweat glands secrete perspiration helping cool the body. Skin blood vessels dilate, capillaries become flushed with warm blood, heat radiates from skin surface
Response: body temp decreases and heat loss centre in hypothalamus shuts off

Question 2

Describe how your body responds to cold

Answer 2

Stimulus: decrease in body temperature
Sensor: skin receptors, blood is cooler than hypothalamic set point
Integrator: activates heat promoting centre in hypothalamus
Effector: skin blood vessels constrict, blood is withdrawn into deeper tissue to minimize heat loss from skin surface. Shivering causes heat generation
Response: body temp rises, heat promoting centre shuts off

Question 3

Response to heat: simple

Answer 3

Brain detects rise in body temp

Hypothalamus sends signal to sweat glands to start sweating and blood vessels to dilate

Evaporation cools body and more blood flows to skin where is loses heat

Question 4

Response to cold: simple

Answer 4

Hypothalamus sends message to organs and tissues to increase temp

Blood vessels contract
Smooth muscles around hair follicles contract (goose bumps) to trap air near skin
Shivering to generate heat

Question 5

What happens in prolonged cold exposure ?

Answer 5

Increase in brown fat (babies) which is efficient at generating heat , protects them and organs from cold environment

Question 6

What are exercise endotherms

Answer 6

Organisms that have to move to generate body heat by maintaining core body temp. Example. Bees

Question 7

Describe fur distribution

Answer 7

Dogs have uneven distribution of fur (not a lot on belly) and curl up when cold to cover exposed surfaces

Question 8

Why do elephants have big ears

Answer 8

Blood flows through ears for heat

Question 9

Why do dogs pant

Answer 9

Increases heat moisture therefore cools them

Question 10

What is thermoregulation? Where is it controlled ?

Answer 10

The maintenance of body’s temperature. Endothermus (like us mammals) maintain constant body temperature despite surroundings

Controlled in the hypothalamus of the brain