Homeostasis

1.   Homeostasis

- maintenance of internal environment within cells (tissue fluid + blood plasma).

- has 3 functional components: receptor, control centre + effector.

- 2 types of mechanism:

a.  Negative feedback.

b. Positive feedback.

- 2 types of animals (that respond to the fluctuations in temperature): endotherms + ectotherms.




Ectotherms



Endotherms











 

 

  








 

2.   To maintain a stable body temperature à organism needs to balance heat gain with heat loss.

3.   Heat gained/lost thru:

-  conduction,

-  convection

-  radiation,

- evaporation (heat lost only).

4.   Ectotherms - exhibit behavioural thermoregulation.

5.   Endotherms - show physiological + behavioural thermoregulation

6.   Internal body temperature à sends impulses to hypothalamus (via blood vessels + afferent nerves respectively).

7.   In thermoregulation:

-   receptors (thermoreceptors) = nerves beneath the skin,

-   control centre = hypothalamus

-   effectors = sweat glands + blood capillaries (beneath skin).



Endotherms show physiological and behavioural thermoregulation

 

Ectotherms exhibit behavioural thermoregulation


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