Page 140 - The Miracle of the Blood and Heart

THE MIRACLE OF THE
BLOOD AND HEART

they to do so, they would accumulate inside the vessels—clot,
in other words—and lead to vein blockages. The blocking of
just a single vein leading to the brain generally results in a
stroke, or death.
These cells' adhesive properties emerge only when the
endothelial tissue in a vein is damaged in some way. When the
endothelial cells are harmed, the structural protein under-
neath them, known as collagen, is exposed. To the thrombo-
cyte, the structure of collagen is very different from that of the
cells lining these veins, and so their adhesive properties
immediately come to the fore.
From 15 to 20 seconds after the opening of a wound, the
clotting process begins. Thrombocytes arriving at this region
deposit there the substances they contain, one of which is
ADP, which causes a number of changes in the thrombocytes'
characteristics. The thrombocytes begin to swell, assuming
irregular forms. Numerous protrusions extend from their sur-
face, which greatly increases their adhesive properties. This
change taking place in the thrombocytes is a vital one, because
the other thrombocyte cells, traveling haphazardly in the plas-
ma, adhere to these thrombocytes that have undergone this
alteration. The ADP deposited in the environment is the mes-
senger that notifies the other thrombocytes of the situation.
This phenomenon takes place exceedingly rapidly. The
wound inside the vein is shortly blocked up by means of this
cooperation among thrombocytes, setting up the necessary
condition for the subsequent process of blood coagulation. If
the tear in the vein is a small one, then the thrombocyte
plug alone is sufficient to halt the blood flow. 58
The healing process goes further than this, how-
Harun
Yahya

138