Page 240 - The Errors the American National Academy of Sciences

The Errors of the American National Academy of Sciences

brings others to the same location. Working together, these cells even-
tually close up the wound. Then, the thrombocytes die, after having
served their purpose. The way they sacrifice themselves is just one
part of the blood clotting system.
Another protein that brings about blood clotting is thrombin. This
substance is only produced where there is an open wound. There must
be neither too much nor too little produced. Moreover, production
must occur and stop at just the right times. So far, more than 20 bodily
chemicals have been identified as playing a role in the production of
thrombin. These enzymes can trigger its reproduction or halt it. The
system is so controlled that thrombin only forms when there is injury
to tissue. As soon as all the enzymes needed for blood clotting have ar-
rived, thrombin trims some protein chains in fibrinogen. The trimmed
protein, now called fibrin, soon form a network. This network covers
the area where the blood is flowing out. The thrombocytes in the blood
also attach themselves to this network. As this accumulation grows
thicker, it stops the flow of blood by acting as a plug. What we know as
a blood clot is the plug formed by this accumulation.
When the wound is completely healed, the clot falls apart.
This system—which brings about the formation of a blood clot,

and either strengthens or removes it, as necessary—possesses the fea-
ture of irreducible complexity. The clotting of the blood emerges from
a chain of events in which one component spurs another into action.
Adiagram setting out the process appears on page 240. It can be seen
at a glance just what a complex process is involved. The system works
flawlessly, right down to the smallest detail.
What would happen if even the smallest thing were to go wrong
in this magnificently functioning system—if, say, there was blood
clotting in the absence of any wound, or if the scab forming over the
wound came off too easily? There is only one answer to these ques-
tions. In such an event, the bloodstream to such essential organs as
the heart, liver, or brain would be clogged with clots. That, in turn,
would inevitably end in death.

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