Thermoregulation in the Body

Thermoregulation centre, brain, automatic control, body temperature, heat, cold, shivering, sweating, vasodilation, vasoconstriction, erector muscle.

Introduction

When it gets hot, or when it gets cold, our body reacts to it naturally. We have an automatic control centre that helps our body temperature maintain itself at around 37° Celcius. But why? What is the point of staying at this temperature, and what happens when our body goes above or below this temperature?

So, What Happens?

Let's take heat for our first example here. When we get hot, what happens? You want to strip some clothes off (please, not all of them!), but also, you end up sweating. This is a response of your thermoregulatory centre that tells your body to secrete water and salty solution on to your skin. This then makes you cool down, because the water content is evaporated. The salt content then helps to cool you down.

When this happens, and your body is hot, your blood vessels get smaller. This is known as vasoconstriction. Like your eyes when they dilate (the pupils get bigger), your blood vessels (arteries and capillaries) can also become bigger. Here's a bit of physics for you: if you have a larger area in your body where heat is given out, it will take less time to cool down. Without this response from your circulatory system, you will remain hot for longer.

Is It the Same When Cold?

Yes, in effect. When your body gets cold, your thermoregulatory centre reacts to it, by making you shiver. This is when your muscles contract quickly to enable your body to create a shock of energy through the process of respirationGlucose + Oxygen  Carbon Dioxide + Water (+ Energy), which in turn warms you up. Of course, when you are cold, you most likely put on some more clothes like a jumper or coat.

Interesting fact: when a person dies, their body decreases in temperature by 1.5 degrees an hour. This is how we know how long roughly someone has been dead for during examination close to the time of death. Other signs then take over.

Once again, your circulatory system gets involved with this issue as well. When we need to warm up, our blood vessels become constricted. This means that close to the skin, the blood vessels become smaller. This process is called vasoconstriction. It just means that there is less blood near the surface. When you're cold, you'll notice it by your fingers and toes going white. This is a normal response, and eventually means that you will warm up.

Another thing that happens when you're cold is that you will get goosebumps and your hairs will stand on end. This again is a natural response. This is because you have little muscles called erectors that contract and push up your hairs on end. This allows heat to be effectively trapped around our skin which then allows us to heat up a little.

How Does This Involve the Brain?

Well, put simply, it is an automatic control centre, and is linked to homeostasis, which is a series of control centres that help regulate your body in different methods. They all interact with the brain to make light and efficient work of your regulated and automatic responses to the environment around you.