Wound repair (Introduction)

by David Turell , Saturday, April 18, 2015, 15:47 (3293 days ago)

It shows how complex is the 'knowledge' that living organisms carry to make a repair:-"A Form of Knowing. I spoke a moment ago of molecular and cellular movements that seemed to be both meaningfully directed and unprogrammed. Here is a more concrete example. It deals with the fiendishly complex and coordinated response to a kind of challenge — a wound — that is always unique in its countless details. That is, the organism is facing something that neither it nor its ancestors have ever faced before in just this way. The description is offered by English biologist, Brian Ford: -"Surgery is war. It is impossible to envisage the sheer complexity of what happens within a surgical wound. It is a microscopical scene of devastation. Muscle cells have been crudely crushed, nerves ripped asunder; the scalpel blade has slashed and separated close communities of tissues, rupturing long-established networks of blood vessels. After the operation, broken and cut tissues are crushed together by the surgeon's crude clamps. There is no circulation of blood or lymph across the suture. 
Yet within seconds of the assault, the single cells are stirred into action. They use unimaginable senses to detect what has happened and start to respond. Stem cells specialize to become the spiky-looking cells of the stratum spinosum; the shattered capillaries are meticulously repaired, new cells form layers of smooth muscle in the blood-vessel walls and neat endothelium; nerve fibres extend towards the site of the suture to restore the tactile senses . . . These phenomena require individual cells to work out what they need to do. And the ingenious restoration of the blood-vessel network reveals that there is an over-arching sense of the structure of the whole area in which this remarkable repair takes place. So too does the restoration of the skin. Cells that carry out the repair are subtly coordinated so that the skin surface, the contour of which they cannot surely detect, is restored in a form that is close to perfect. (Ford 2009) -"It is not being radical to point out that we can't even begin to picture the unfathomable movement of trillions of molecules and millions of cells in the damaged area. The story is directed toward a desirable conclusion that you and I know very well — restoration to normalcy of a damaged body part — but how does the story “hold together” at the level of molecules and cells, which certainly do not “know” what we know? And yet, quite obviously, in some objective sense the necessary knowledge is there in the organism. It knows. It gets the job done."-From one of my favorite authors, Stephen Talbott:- http://www.netfuture.org/2012/May1012_184.html#2