Thursday, November 29, 2012

Stress and Why to Avoid It

This article talks about the definition made up by neuroscience for 'Stress'. It discusses the different types of stress, what happens and is damaged when it comes into play, and why it does all of that.

Let's first determine the definition of the stress we're discussing here (I like making up short definitions of things at the beginning of articles, it's very useful):

"Stress is when your body (or a part of it) is forced into a non-natural state"

For example: too little sleep, too little food eaten, a wound, a broken leg, too much to do, etc.

So we're not talking about when people say 'Oh my, I'm so stressed out!' when they have a lot of worries, we're talking about people not being in a comfortable state for a long time (which means: longer than a few days is not good for you).

Let us introduce a good old friend of ours, a part of your brain called the hippocampus.

Long ago people thought that the brain was a static organ -> once created, its development is complete, no mitosis (creation of new cells) will happen anymore.

As a result they thought that brains are not flexible and damaged brains cannot recuperate. Both of these statements are not true!

All great, but what does this have to do with the hippocampus? Well, the hippocampus is the place where new information is saved (which is done by creating more brain cells with more connections!), but it is also the part of the brain where an hormonal stress reaction has to be stopped. If the hippocampus fails to stop this stress reaction, it will be damaged and less or no new neurons will ever be formed.

Hormonal Stress Reaction

So what is this reaction? There are two different scenes: Acute stress and Chronic stress.Both of these are controlled by the orthosympathic nerve system, which is the system of your body that's made for action or carrying out labor.

Acute Stress

Acute stress happens for example when you see someone walking towards you with a very angry face, then you become nervous. And when you do that, your adrenals are stimulated (actually theadrenal medulla).

And they then produce 2 stress hormones:

- Adrenaline
- Nor-adrenaline

Adrenaline is known as a quick stress hormone, with a short term action. Its concentration in
the blood rises enormously fast (within a few seconds), but also releases the stress relatively quickly.

Chronic Stress

Chronic Stress happens when you're in this situation for a long period.

Your hypothalamus in this case produces CRH (Cortisol Releasing Hormone).

This stimulates the pituitary to produce ACTH (via blood).

And then finally this stimulates the adrenals to produce cortisol.

Cortisol is a slow stress hormone, with a long term action. Its concentration in the blood rises slowly (within a few hours), and therefore you can be in this stress situation for a long time. When you for example have slept far too little for the past few weeks, you can still stay awake in class because this stress hormone makes sure you 'survive'.
But once this process takes place day after day after day, bad things will happen.
- Your muscle tissue will dissolve

- Diabetes

- Your immune system is suppressed (infections become fatal)

- Brain damage!

And why is the brain damaged? Because if the hippocampus fails to remove all the cortisol in your body, the cortisol will slowly break and damage the hippocampus (and you do not want that).

About Cortisol

Research has been done on cortisol, and the following statements were concluded:
- Cortisol can be brought into an embryo via its mother

- If rats are taken away from their mother after birth they are also under stress

- If your hippocampus is damaged, the damage will stay

- Adults who had a lot of stress in their childhood will be more susceptible to stress (their cortisol level will rise more quickly than usual)
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