Page 27 - The Miracle of the Immune System

25
Besieged Castle: The Human Body

In this picture,
you can see the
macrophages
located in the
lung tissues.
They eliminate
the dust parti-
cles in the air
we inhale.

Protection in Respiration

One of the courses our enemies take to enter our body is the respira-
tory tract. Hundreds of varied microbes, which are present in the air we
inhale, try to gain entry to the body through these passages. However,
they are unaware of the barrier set up against them in the nose.
A special secretion in the nasal mucous retains and sweeps out about
80-90% of the micro-organisms that gain entry to the respiratory system

directly or through dust particles or other substances.
In addition, the tiny hairlike structures (cilia) on the surface of the
cells of the respiratory tract beat upward, causing a current that carries
foreign particles to the throat where they are swallowed and disposed of
by acid in the stomach. The coughing reflex and sneezing facilitate this
function.
The microbes that are able to surmount these barriers and reach the

alveoli (lung, bronchus and gingiva) will be ingested by phagocytes. Aft-
er this phase, phagocytes become mobile and drift upwards with the mi-