Homeostasis ROCKS!

Well.... Any idea what homeostasis is? It seems a really unique and isolated word that not many has seen, except for biology students. Thus, I decided to post this up so as to share additional information with all of you!

Homeostasis is the maintainance of a stable and constant internal environment of an organism.
Let me give you an example:
Stimulus- Very hot weather
Receptor- Hypothalamus in your brain detects decrease in water potential
Effector- Pituitary glands secretes more ADH (anti-diuretic hormones)
Control centre- sends suitable responses and receives the negative feedback
Response- More water will be absorbed in the body
Feedback- Send messages back to the brain when it has reached norm [Negative Feedback]

Heat is produced in the body in 3 ways:
1) Breakdown of carbohydrate and lipids
2) Hormones that control metabolic rate
3) Physical exercise the requires muscles

Heat is lost in 4 ways:
1) Radiation is proportional to the temperature difference and accounts to 50% of heat lost.
2) Conduction refers to 2 surface in contact (Heat molecules transferred frm hot to cold).
3) Convection refers to the rate of air and water movement.
4) Evaporation where heat converts liquid to gas and allows latent heat frm body to be lost.

Lets's share some new terms!
a) Poikilothermic refers to those that are unable to regulate their body temp by physiological means.
b) Ectothermic are those that are dependent to the environment temp.
c) Homeothermic are those that are able to maintain a fairly constant body temp.
d) Endothermic are those that are independent of environment temp.

Lets take a look at what happens during different conditions!

Overheating
When temperature is higher than usual, a few things might take place:
1) Sweating occurs to remove latent heat of vapourisation via evaporation.
2) Vasodilation of the arterioles will occur to allow more blood to flow near the surfaces of the skin to remove heat via radiation, conduction and convection.
3) Reduction of hormones such as adrenal and thyroid that will increase metabolic rate

All these occurs until body temp has reached the norm.

Overcooling
When temperature gets too cold, a few things might take place:
1) Sweating will not take place anymore
2) Increase of metabolic activities such as shivering to increase heat production
3) Erector muscles will contract and thus causing hair to erect to trap hair and form a layer of insulation to reduce loss of heat.
4) Vasoconstriction of arterioles will take place so as to reduce amount of blood flow to result in lesser heat to be lost thru radiation, conduction, convection.
5) Curl up to reduce surface area for heat loss.

All these occurs until body temp has reached norm.