Introduction

This tutorial will take you through the CRH release caused by the Generalized Stress Response.

You will navigate through this tutorial using the buttons at the top of the screen.

The tutorial will ask you questions. Click on your chosen answer to see feedback; click the answer again to make the feedback disappear. When you're finished with one page, click the navigation button for the next page to move ahead.

Have fun! Click on button '1' to see the first page of the tutorial.

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CRH stands for

Corticotropin Releasing Hormone

You can tell a lot from this name, if you think back to your Anatomy and Physiology.

Cortico -- means relating to the adrenal cortex
Tropin -- means growth stimulating
Releasing Hormone -- means this hormone will cause the corticotropins to be released.

So the name means, 'a hormone which will cause the release of compounds that make the adrenal cortex grow.'

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In this case, the Corticotropin Releasing Hormone will tell the anterior pituitary to release Corticotropin, also called Adrenal Corticotrophic Hormone, or ACTH.

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The hypothalamus and pituitary are trying to keep one of these hormones at a stable value by turning the adrenal cortex on and off. But which one? aldosterone

cortisol

testosterone

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What kind of feedback loop would you call this?

positive

negative

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Cortisol is called a glucocorticoid. This is because the first effects of cortisol that were discovered were effects on glucose metabolism. In fact, though, cortisol affects almost every system in the body.

Here's a list of the effects of cortisol.

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Cortisol helps the sympathetic system raise blood pressure by increasing heart strength and making arterioles more responsive to the sns.

In short-term emergencies, cortisol also helps the sympathetic system increase muscle strength. How would it do that? calcium loss in urine

actin breakdown

decreased insulin release

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inhibition

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Cortisol depresses immune and inflammatory function in many ways.

First, it blocks prostaglandin production. This is the compound injured cells use to begin an inflammatory response and attract white blood cells like neutrophils and monocytes (which grow up to be macrophages) into the area.

Then, if neutrophils get to the area anyway, cortisol prevents them from leaving the blood and entering the injured tissue.

It decreases the activity of monocytes and macrophages, so there are fewer of these antigen-presenting cells to alert the immune system to the presence of infection...

and, over the long run, it atrophies the thymus so fewer mature T cells will be produced!

But why on earth would you want to turn off your immune system, just when the body is under attack?

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First, the immune response takes a lot of energy. If you're running away from a bear, you don't want your energy to be diverted from the muscles!

Second, the inflammatory response increases blood flow to the injured area. This would divert blood from the muscles -- and it could cause the injured area to bleed more.

Third, when the immune response kicks in, it has effects on the whole body. It can cause a fever, and make you nauseated; it can also give you a feeling of malaise, so you just want to lie around and rest. Not the way you want to be during an emergency!

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