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Life Sciences => Physiology & Medicine => Topic started by: erickejah on 22/01/2009 22:04:46

Title: How is body temperature controlled?
Post by: erickejah on 22/01/2009 22:04:46

What regulates the temperature in our bodies?
Is this different in every person?

Title: temperature/regulation
Post by: Chemistry4me on 22/01/2009 22:12:21

The skin is the largest organ in the body, and plays an essential role in the regulation of heat loss. There are two layers: an outer, epidermis and an inner dermis.
The dermis contains a number of structures concerned with termoregulation:
•Blood vessels- the wider they are, the more blood flows through them and the more heat is brought to the skin.
•Sweat glands- these deep intuckings of the epidermsi open on the outer surface of the skin-they secret sweat, obviously, which, when it evaporates, cools the skin
•Sensory nerve endings- some are sensitive to changes in temperature.
•Hair follicles- attached to each follicle is a small erector muscle which raises the hair, producing goosebumps.

Title: How is body temperature controlled?
Post by: Chemistry4me on 22/01/2009 22:13:01

Theres more if that is not enough for you [;)]

Title: How is body temperature controlled?
Post by: Chemistry4me on 22/01/2009 22:27:42

Alright, I'll take that as a yes!  [:D]

A fall in body temperature is detected by a part of the brain called the hypothalamus, I'm sure you've heard of it. This sends out more impulses to the skin arterioles via sympathetic nerves, causing the arterioles to constrict, reducing the flow of blood (and therefore heat as well), to the skin. A rise in temperature causes the hypothalamus to send more impulses to the sweat glands, stimulating them to increase sweat output.

Beneath the dermis is a layer of adipose (fat-storage) tissue. The cells are huge, each containing a single enornous fat droplet. Besides acting as a energy reserve, adipose tissue act as a heat insulator.  [:)]

Title: How is body temperature controlled?
Post by: Chemistry4me on 22/01/2009 23:00:07

Even when asleep, energy is needed for keeping warm and for other important processes. This minimum rate of metabolism is called the basal metabolic rate (BMR)
The BMR is under the dirsct control of the hormone thyroxine, secreted by the thyroid gland in the neck. Thyroxine contains iodine, which is why this mineral is needed in the diet.
The thyroid gland does not monitor body temperture, that is done by the hypothalamus in the brain. The hypothalamus stimulates the pituitary gland just beneath it, via a hormone. In turn, the pituitary gland stimulates the thyroid by (another) hormone called TSH. The thyroid is prevented from over-stimulated by negative feedback-thyroxine actaully inhibits the secretion of TSH, so a rise in thyroxine tends to inhibit its secretion and vice versa. All very comfusing  [::)] [::)] [::)] [::)] [::)]

Title: How is body temperature controlled?
Post by: Chemistry4me on 22/01/2009 23:25:02

As for your other question, humans are homeothermic - we can regulate our body temperatures at a near constant level. Normal body temperature in humans averages 37°C (it is slighly higher in the evening and a little lower in the morning).

Title: How is body temperature controlled?
Post by: erickejah on 22/01/2009 23:38:00

cool, I wont ask anymore questions until I memorize this, this is really interesting [:D] [:D].
tx again C4M.

Title: How is body temperature controlled?
Post by: Chemistry4me on 23/01/2009 02:10:34

Quote from: erickejah on 22/01/2009 23:38:00

cool, I wont ask anymore questions until I memorize this, this is really interesting [:D] [:D].

You're going to be a busy boy trying to remember all of this stuff!

Title: How is body temperature controlled?
Post by: erickejah on 25/01/2009 01:41:46

Got it  [;D] [:D] [:D] [;D].