Page 31 - The Miracle of the Blood and Heart

Blood: The Incomparable
Liquid of Life

and in the right place. Thanks to its shape, the red blood cell
can load up with far more oxygen molecules than it could if
shaped like an ordinary cell, and is able to carry them more
easily to the tissues where they are needed.
Red blood cells' flattened shape is also vital in terms of
these cells' unimpeded passage through the tiny capillaries.
They are the smallest cells moving in the bloodstream. This is
of vital importance for them to carry oxygen to every point in
the body. Sometimes, however, red blood cells find themselves
facing capillary vessels of very minute dimensions. These
veins, which can sometimes be only 5 micrometers in across,
are too narrow for red blood cells with a diameter of 7 to 8
micrometers to pass through. 17 But red blood cells must pass

Key:
1 micrometer =
1/10,000 cm or
1/1,000 mm

7-8 micrometers

Surface view of an
erythrocyte

Sectioned view of an
erythrocyte

Despite being the smallest cells in the circulatory sys-
tem, red blood cells still encounter some very nar-
row passages. The 5-micrometer-wide narrow tun-
nels represent very difficult tunnels for these red
blood cells, approximately 7 to 8 micrometers in
Adnan
size, to pass through.
Oktar

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