Your elemental composition and a few interesting facts

Your body consists of about the following:

• 65% Oxygen
• 18% Carbon
• 10% Hydrogen
• 3% Nitrogen
• 1.5% Calcium
• 1% Phosphorous
• 0.35% Potassium
• 0.25% Sulfur
• 0.15% Sodium
• 0.15% Chlorine
• 0.05% Magnesium
• 0.0004% Iron
• 0.00004% Iodine

There are obviously considerable variations from person to person. Ladies differ from men - for instance men are true iron men in that they contain 1.65 times as much iron as ladies.

Also, there are traces of other elements but the above list covers the major components.
The elements are combined in many, many forms.
That's what chemistry and biochemistry are about.

What would happen if you took this amount of each of these elements and mixed them - enough to simulate a 70 kg person?
Reactions would begin right away - quite likely causing heat. If you added a spark to this combination it would explode, then burn and smaller violent reactions would be seen.

Would it validate the "Big Bang Theory"?

Well, maybe on a smaller scale.
You certainly would not end up with a human! If you were patient and could wait a few million or billion years perhaps those mixed elements would evolve into some lifeforms. A nice thought, but I do not have the time. Still it would be fun to look at combining many of those elements and studying the reactions - putting equations to them - a topic that can be covered in future posts.

Now let's get back to the composition of humans:
Our bodies are a more delicate combination of these elements - lots of water, a good bit of protein, fat and bone. Sugars can be found  in our blood, as well as oxygen, carbon dioxide and many more compounds, all made of systematically arranged elements, or molecules, which are arranged in bigger groups such as cells, which again are arranged to create organs, which make up the physical form of mankind and other lifeforms.

Even the air in our lungs is part of our make-up - nitrogen and oxygen for the most part.
How much air do you contain? We would need to know your lung volume - if it is 5 liters then you have about 6 g of air (1.2g per liter x 5 liters) .

Of that about 21% or 1.26 g is oxygen. It seems so little. Think of the freedive world record holder, Herbert Nisch, who descended an incredible 214 m strait down into the ocean on a lung volume of about 12 liters (~3 g of oxygen). That is a 428 m round trip on 3 grams of oxygen - rather efficient, I would say. Yet we humans are terribly inefficient oxygen conservers compared to seals and other marine mammals.

So, physically, humans and animals, are complex combinations of elements. All the elements in the above list can be analysed for and many of their combinations (or molecules) can also be analysed using analytical instruments and other chemical means.
In recent years many simple instruments used to analyse such molecules have been developed - for example we could analyse Herbert Nisch's blood using a pulse oximiter (oxygen meter) just before he dives by clamping a small noninvasive device to his fingertip or earlobe - it reads the colour of his blood in time with his heartbeat - the redder the more oxygen, when he surfaces he is definitely close to passing out because he depleted a lot of that 3 g of oxygen that he took down with him. Now the clip-on oxygen meter would read a much lower level. The red colour readings must be made at a consistent time in his pulse cycle because with each heartbeat because the little capillaries in the fingertip or earlobe actually expand with each heartbeat and would give more red at the time of a pulse rather than after the pulse when they shrink.

On the topic of blood, the red colouration comes about from haemoglobin, the oxygen carrier that transports oxygen from the air to our bodies. If you train hard for an event, perhaps the Iron Man, or deep freediving as in Mr Nisch's case, the haemoglobin levels in your blood will change. They must, so as to cope with the hard work (oxygen starvation). Your body builds up more haemoglobin in the blood - that is one of the key parts of training for such an event. I do some freediving as a hobby. After extensive long duration dive sessions I find running to be extremely easy as compared to normal - it is surely related to the boost in my haemoglobin levels thus making oxygen transport efficient and the run becomes easy.

So chemistry is involved in getting fit too. So why not go do some chemistry on the sports field after work or school - you cannot escape it even if you try, so rather become more aware of how you do it...

One of my former Lecturers, Prof Peter Loyson, regularly suggested that we imagine that we have been shrunk down to molecular size and imagine what the molecules look like and how they interact with each other - we often used to laugh at this concept, yet strangely enough I find myself doing exactly that - trying to picture what is going on. You even see it shown in some movies these days - the film simulates an activity in the blood or muscles.

Hey! It is The International Year of Chemistry so why no try it out...

Imagine you are an observer in you blood stream, lung surface, or even inside an egg you are cooking.

What is going on in your internal organs and "plumbing"?


p.s. If you wish to see a lot more detail of what blood consists of click on the link.