The Coolidge examiner., 1935-07-26

body. The arter-
les lead away
from the heart and the veins re-
turn II TO the heart. The heart Is
Itself part OF the blood vascular
system
The heart consists OF n left and
right chamber. The muscle coat
Is very thick, and, In comparison.
the outside covering and the IN
side lining are very thin.
Contracting normally u times per
minute. the heart acts as a pump be-
tween the veins and the arteries. II
maintains a constant pressure Of
blood in the arteries.
The arteries. however, are not
passive In this matter OF pressure.
They are made up of muscle tissue
with a dense outside coat 10 pre-
vent overdistension and an inside
lining that is thin and slick. This
muscle coat gives n little with each
heart beat so as 10 absorb the shock
and TO keep the pressure of the
blood constant.
The arteries are constructed upon
the principle Of a tree. The big
trunk Is attached TO the heart, and
the large branches 20 TO the stom-
ach. the lntestines. the kidneys and
other body organs and one to each
arm and leg. The large branches
in turn break up into smaller
branches. which finally result In MI
croscopic caplllaries.
There are many thousands OF these
infnitesImally tiny capillarles In
every square inch Of tissue In your
body. The blood flows through them
very slowly. AS soon as the blood
gives off its load OF food and gases.
II takes up waste products from
the body tissue, and starts back to
the heart through the veins. The
venous system Is like another tree.
When the blood Is distributed
properly, all the capIllares have
an even supply OF blood. But after
meal, the stomach requires a
more than normal amount TO circu.
late through II. so less blood circu-
lates In the brain.
Now hardening OF the arteries
means that the walls of the arter-
les have lost their power to expand
with the beat OF the heart and to
contract with It's rest period. So
instead OF absorbing the shock OF
the rush Of blood with each beat
OF the heart, as Nature intended,
they simply act as a rigid tube
that passes this strong force un-
abated on 10 the smaller arteries
which in turn pass Ii on TO the
tiny capillarles. And the thin walls
OF these smaller arteries and capil-
laries were never meant TO with
stand such high blood pressure. So
there is apt TO be trouble. One OF
the tiny blood vessels may break.
II this happens In the brain we
call 1t apoplexy and say the person
has had a stroke.
The valves of the heart are thin
walled leaf-like structures that
close the chambers of the heart.
Sometimes bacterial infections cause
Inflammation Of these, and the heal
Ing process leaves scars. The effect
of these scars Is to shorten the
valves and pull them out of place,
with the result that there Is a
leakage between two OF the heart
chambers. Now the muscle wall Of
the heart always has TO thicken
10 force blood through the heart.
The leaking valves cannot hold the
blood back as they should. so the
heart becomes thicker and larger
than Is normal for Ii 10 compensate
for the defect. Then in later life,
when the arteries become hardened.
the blood pressure is increased, and
the heart has difficulty in thicken-
Ing fast enough TO carry the
pumping load due to backflOw
through the leaking valves. A per-
son with such a condition, known
as endocardltis, must slow down
his daily life to conform to the
hearts action.
Sometimes, too, the heart muscle
itself may have been damaged from
some infection in early life, such as
diphtheria. Then when hardening Of
t'ie arteries causes changes in cir
culation and in blood pressure, the
heart cannot compensate fast enough
and condition called nyocar ditis
develops.
The whole circulatory system acts
as well-organiZed unit. The heart
cannot be separated from the arter-
les and capillaries, and the arteries
cannot be separated from the heart
and capillaries. When one part
becomes abnormal, the whole sys-
tenn must readjust itself TO the
new conditions. Ordinarily the alb
normality is progressive, and hence
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