Posts Tagged ‘wound’

When you Wound a Finger, How Does the Body Know what Shape to Rebuild?

September 16, 2011

Let’s assume you cut your fingers with a bread knife and there’s a gaping wound. You can just see the skin layers cross-sectioned and maybe even the whiteness of the bone before the red liquid floods it all. What’s amazing is that a few weeks later, your finger will look just like it did before you cut it.

How is this possible you ask, how does the body know? Surely, this is proof that there is some external intelligence, something beyond matter that knows or stores information about matter or at least about the material body and that can steer matter or the body.

Similarly, one might ask: How is the world possible, why is it the way it is, how come everything happens just the way they happen? Surely, this is proof that there is some external intelligence, something beyond matter et cetera et cetera.

The problem with Intelligent Design is that there’s no reason to assume an external intelligence behind a process when the process is self-explanatory. Instead of trying to find a top-down, simplified reason behind everything, we should look at all the details of the complexity that form the whole of the process  bottoms-up.

In the case of the finger, and indeed the growth of a child, we look at all the biochemical processes that form a whole human body.

When a blood vessel is damaged, the endothelium, a layer of cells on the inside of the blood vessel wall, releases a protein that binds collagen. Then blood “platelets bind to collagen with surface collagen-specific glycoprotein Ia/IIa receptors. This adhesion is strengthened further by additional circulating proteins vWF, which forms additional links between the platelets glycoprotein Ib/IX/V and the collagen fibrils,” and the chain reaction started this way leads to clotting. –

“Numbers of monocytes in the wound peak one to one and a half days after the injury occurs.[18] Once they are in the wound site, monocytes mature into macrophages. The spleen contains half the body’s monocytes in reserve ready to be deployed to injured tissue… Stem cells of endothelial cells, originating from parts of uninjured blood vessels, develop pseudopodia and push through the ECM into the wound site to establish new blood vessels.” –

To answer the question, no body knows anything here, the cells just do their jobs. There’s no command centre with a large map of the body on display whence individual cells get their orders and then using compasses they orient themselves to a specific place. Instead the body structure is maintained by having the remaining cells on the edges of the damage build the body back up from the edges inwards. When they  (and by them I mean the copies of them) bump into each other they stop growing, sometimes the process is less than perfect and we end up with scars that all look differently.