Page 99 - The Miracle of Hormones

The Adrenal Glands

ies that ensures the vital organs receive a greater supply of blood at the
times of danger, and to do this, they dilate the blood vessels going to the
heart, brain and muscles. The cells surrounding the vessels obey the
adrenaline and supply the extra blood required by the heart. In this way,
the extra blood needed by the brain, muscles and heart is supplied. 24
While dilating the blood vessels going to the heart, brain and mus-
cles, adrenaline constricts the vessels that supply the liver and the skin to
ensure extra support needed by the body. There is another reason for the
reduced amount of blood pumped to the skin: in the likely case of a
wound, the amount of blood loss would be reduced. The reason for pale-
ness observed in the skin in times of excessive excitement is because less
blood is pumped to the skin then. 25
An error never occurs that di-
Hypothalamus
lates the vessels going to the heart
(or the brain) that constricts vessels
going to the liver (or skin); the
adrenaline molecule knows what it
must do. A microscopically
Carotid
sinus small hormone adjusts the
diameter of the hun-
dreds of blood vessels in
your body where the
Heart
blood is to be directed.
For every organ in the
Arteries body, the action of adrenaline
is different; when the adrenal-
Adrenal gland
ine molecule goes to the
blood vessels, it causes them
to dilate; when it goes to the
heart, it quickens the contrac-
tion of the heart cells. This
In times of danger, the body goes into a
makes the heart beat faster
state of alarm by means of a link be-
tween the brain and the adrenal glands. and supplies the extra

97