Blood Clotting: shrinking scabs (Humans)

by David Turell , Friday, November 10, 2017, 00:50 (2570 days ago) @ David Turell

If you have ever cut your skin you know about scabbing which forms a rigid blood stopping protective layer after about an hour. Healing occurs under it. Clotting is an amazing process of over 17 blood factors triggering one after the other in a cascade reaction. It must be controlled to stop after the wound is covered. If internal it must be stopped before the whole body is clotted (!):

https://medicalxpress.com/news/2017-11-blood-clots.html

"Blood clotting is the "Jekyll and Hyde" of biological processes. It's a lifesaver when you're bleeding, but gone awry, it causes heart attacks, strokes and other serious medical problems.

"If a clot grows too big, pieces dislodged by blood flow (emboli) can block downstream blood vessels in the lungs or brain, leading to life-threatening complications such as pulmonary embolism or ischemic stroke. Therefore, once a clot forms, even for beneficial reasons, it must shrink and disappear after wound healing starts to maintain normal blood flow.

"While scientists know a lot about how blood clots form, relatively little was known about how they contract—a slow process that takes an hour to complete.

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"As a result of injury or inflammation, platelets in blood get activated, become sticky, and bind together and with a stringy protein called fibrin to form a mesh-like plug (the blood clot) that stops bleeding into tissue. Platelets play a central role in clot contraction, but, until now, scientists haven't been able to show exactly how they accomplish this.

"As described in the paper, clot shrinkage occurs when platelets form hand-like protrusions called filopodia. These filopodia then attach to fibrin fibers and reel them in using the same hand-over-hand action used by a person pulling on a rope. The platelets retain the fibrin in tiny, tightly wound bundles, therefore remodeling the fibrin mesh to make it more dense and stiff. The reeling action also brings platelets and clusters of platelets closer together, reducing the overall volume of the clot followed by complete dissolution by fibrinolytic enzymes.

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"Alber said the findings highlight a new role for filopodia, which were previously thought to help cells move around and sense their environment.

"'Until now, we knew very little about how individual platelets or small clusters of platelets exert a contractile force on fibrin fibers and how this tension collapses a clot's structure and reduces its size," Alber said. "Through this research, we have revealed a novel function for filopodia, which is their ability to re-arrange the fibrin matrix to cause clot shrinkage."

Comment: Multicellular Life could not continue to survive, unless a protective mechanism was present from the beginning to protect the circulatory blood system from leaks. This is the sort of system hat is so complex it had to begin in tact all at once, again implying design by God. No way to develop it step by step through multiple coordinated mutations.