Page 30 - The Cell in 40 Topics

The Cell in 40 Topics

Figure 17.
There are some 2 kilograms (4 pounds) of calcium
in the adult human body.

is to be transfused into a patient await-
ing an operation—but that
there is a problem. This
blood is calcium-defi-
cient, although the extent
of this deficiency has not
been determined.
You are also given a large
bowl full of powdered calcium
and told to make good the defi-
ciency (Figure 18).
What would you do?
First, you would have to
measure how much calcium is
lacking. In order to do this,
however, highly advanced
technological equip-
ment is necessary, and
you lack both the time
and the means. That being so,
there is little you can do.
Yet in the body of every human being, there is a magnificent mecha-
nism that calculates the level of calcium at every moment and takes the nec-
essary measures. The thyroid gland and the parathyroid gland—another
hormonal gland buried inside the thyroid—function in line with a most ra-
tional plan in order to maintain the calcium balance in the body. The
parathyroid gland's sole function is to measure the amount of calcium in
your blood, 24 hours a day, throughout your entire life, and to keep it at the
ideal level (Figure 19).
The parathyroid gland controls the level of calcium in the blood by

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