Page 214 - The Miracle of the Blood and Heart

THE MIRACLE OF THE
BLOOD AND HEART

Endothelium
ARTERY

Capillary
Inner layer Arteriole Venule
Endothelium
Elastic fibers on the outer layer of the
artery provide resistance against pres-
Elastic lamina
sure, such as the powerful heartbeat.
The middle layer consists of elastic tis-
Middle layer
sue and smooth muscles, which are
Smooth muscle
and elastic tissue important with regard to the regulation
of the amount of blood dispatched. The
Outer layer
flat epithelial tissue in the inner layer
(elastic and col-
lagen fibers) has a smooth, literally polished surface
that permits the easy flow of blood by
reducing friction.
Lumen
That the arteries are hidden deep inside the body is a pre-
caution of the greatest importance. Thanks to this, arteries are
not easily damaged. By means of this flawless order, our
Lord—Who created the arteries, the blood inside them and
Who regulates these at all times—has protected humans from
the serious dangers we may encounter. That alone is enough
reason for a person to turn to God and give thanks.
At times of injury, it is generally the veins that suffer dam-
age. But as we shall be seeing in some detail, these do not
carry high-pressure, viscous blood. During injury, therefore,
the blood flowing in a heavy, dense form has the prospect
of clotting easily. In the event that an artery is dam-
aged, however, the bright, high-pressure blood is
Harun
Yahya

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