I don't feel good, I am sick

When we are sick our body begins to do some very strange stuff!
We have a fever, we could eat a refrigerator and two seconds later not even want to eat a small poor piece of bread, we would sleep all day long or would have to " veg out " on our sofa in front of the television set.
But why do we react this way when we get sick? What's happenning inside of us to put ourselves in a such a state?
In fact, it's in our immune system that is sending messages to the brain for him to adopt a good behavior in front of pathogenic.

Let us take the example of the fever:
first of all, it is necessary to know that our normal temperature is 37.2 degrees.
When bacteria or viruses enter our body, the leukocytes and macrophages will make a substance which is going to go to alarm the hypothalamus (a part of the brain).
The hypothalamus will then send a message for the brain to be warmer.
The body feels cold because compared to the brain he is cold, then it puts itself in adequacy with the temperature of the brain.
When the fever goes down, the brain will be the first one to get cooler, and the body needs time to find the normal temperature, so we are hot.
The fever is going to help the increase of the number of white blood cells and is going to allow the liver to block the iron and the copper that bacteria need for growing.

If we look at the causes of the tiredness, when we are sick, and those of our lack of appetite:
It comes from our evolution. In fact, our cells have not understood that we do not have to go hunting any more to feed us, that nowadays the food is easily accessible (unless if you consider that going shopping is similar to running after a mammoth for several hours ^^)
All this is to say that when we are sick, our body needs energy to be cured and defend itself against the pathogenic.
That why, when we get sick, our brain will stop releasing orexine (it is a hormone which is responsible for the desire to move, for the appetite etc.)
The hypothalamus, as is not receiving this hormone anymore, is "telling us" that we are tired and that we aren't hungry …

Well, now when somebody blames you for being soft when you are sick, you will know what to say back!
                                                                                                                               Elise.C