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Showing posts with label Homeostatis. Show all posts
Showing posts with label Homeostatis. Show all posts

Friday 22 March 2013

The Holy Grail - and where to find it

If you were are a 12 year old boy, like Ted, who loves watching the History Channel, you would know all about the Holy Grail.  Depending on your religion, you may know it as a sacred cup linked to certain important Christian events; but there are also Celtic myths about a cauldron with magical powers.  Throughout history, people have been searching for the Grail, from King Arthur to Indiana Jones.

This blog is itself a search for the Holy Grail.

Monty is a big fan of a well-known picture book series called Meg & Mog.  It is about a nice witch called Meg and her black cat called Mog.  Featured prominently is a magic cauldron, which Meg uses to cast her magic spells.  Just click on the above link and all will become clear.


So, we are looking for the Grail

Well, if you have struggled through all of this blog from the begining, you already know where to start looking.  California looks pretty hot, but then again there are some rumours about somewhere in France.  All will be explained, as we proceed further.

Homeostasis

First we need to learn a new word, Homeostasis, if you already know what it means, you are much brighter than me.

Do not confuse it with Homeopathy.  There may be another coincidence here as well.  Those generous people at Wikipedia give us this definition:-

Homeopathy  /ˌhmiˈɒpəθi/ (also spelled homoeopathy or homœopathy; from the Greek hómoios- ὅμοιος- "like-" + páthos πάθος "suffering") is a system of alternative medicine originated in 1796 by Samuel Hahnemann, based on his doctrine of similia similibus curentur ("like cures like"), according to which a substance that causes the symptoms of a disease in healthy people will cure similar symptoms in sick people.  Scientific research has found homeopathic remedies ineffective and their postulated mechanisms of action implausible. The scientific community regards homeopathy as a sham;  the American Medical Association considers homeopathy to be quackery,]and homeopathic remedies have been criticized as unethical.

Now let’s get back to Homeostatis and to help us really understand it, I decided to give a detailed example using the medical condition diabetes.

Homeostatis is a process through which the body's internal environment is kept stable.  For example, when the level of sugar in your blood is too high, your body detects this, an alarm goes off and the body acts to reduce it; conversely when blood sugar is too low, again the body detects this and sends a signal to raise it.  All this happens 24/7 and you do not even need to think about it.  That is, unless you are diabetic.

So we have:-

·         A  receptor, like a tiny sensor that is constantly measuring blood sugar.

·         Positive feedback, when the receptor detects a low level and then tells the body to raise the level of sugar 

·        Negative feedback is when another receptor alarm goes off, and the body needs to lower the level of sugar in the blood. 

·        Homeostatic imbalance occurs when the body is overwhelmed and can no longer regulate itself and regain stability.  Many diseases are indeed the result of such an imbalance; diabetes is but one.

Insulin is the principal hormone that regulates uptake of glucose (sugar) from your blood.  Insulin is released into the blood after eating.  Insulin is also the principal control signal for conversion of glucose to glycogen, for storage in your liver (and muscle cells).

Lowered glucose levels result both in the reduced release of insulin and in the conversion of glycogen to glucose. This is mainly controlled by the hormone glucagon, which acts in the opposite manner to insulin. Glucose is forcibly produced from the liver (where it had been stored as glycogen) and enters the bloodstream.

Both insulin and, its opposite, glucagon are produced in the pancreas.

Summary

So we have a receptor constantly measuring your blood sugar.  You eat a chocolate bar, blood sugar rises fast, an alarm goes off.  Release the insulin !  Insulin is released from the pancreas.  Remove excess glucose and store it (as glycogen) in the liver !  Blood sugar level is falling. Homeostatis restored; panic over.

Then you go for jog in the park.  Receptor detects falling blood sugar.  Release glucagon !  Glucagon is released from the pancreas.  Go to the liver and tell it to start converting glycogen back to glucose !  Blood sugar level is now rising.  Homeostatis restored, panic over.


Back to Ted and the quest for the grail

Ted sometimes finds it hard to explain what Dad’s job really is;   he is not the first to ponder this.  Now, Ted has decided that his Dad can officially be described as a wizard.  This helps me a great deal with this blog. 

We will now opt for the pagan Celtic myth about a cauldron with magical powers, this will be our Holy Grail.  We just need a cauldron, a wizard, some ingredients and a magic spell.  We are nearly there.




We even know part of the spell:- “ homeostatis and channelopathy  .........”


A final few words
In our first two weeks of this blog, we have been busy travelling.  We started in France, went all the way to the Punjab to meet a clever chap called Baldeep in  Chandigarh.  Then we headed over to Palo Alto in California.

The good news is that back at Monty's house, the cauldron is bubbling and the magic already seems to be working.  We just lack a few more ingredients and that elusive spell.