The function of the respiratory system is rather
simple in concept to bring in oxygen from the atmosphere and get
rid of carbon dioxide from the blood. Since oxygen (O2) and carbon
dioxide (CO2) are gases, the process of bringing one in and excreting
the other is called gas exchange. .....
.Air is inhaled
first through the mouth and or nose; aka nasopharynx, were it
is filtered, warmed, as well as moisturized. Air then passes the
Epiglottis and enters the larynx. The air then passes through
the (larynx), voice box and into the trachea. The trachea divides
into two branches, the right and left bronchus. The air then passes
into the bronchi, then to the bronchiole that branch out like
branches of a tree. The branches further divide into the alveolar
ducts, and then down to the individual alveoli sacs, where oxygen
and carbon dioxide exchange takes place.
Oxygen is necessary for normal metabolism; lack
of it leads to death in a few minutes. Carbon dioxide is a waste
product of metabolism; if breathing stops, carbon dioxide will
quickly accumulate to a toxic level in the blood. Thus our lungs,
the
Organs that exchange O2 and CO2 with the atmosphere are vital
since their total failure is quickly fatal.
We have two lungs, one in the right side of our
chest cage and one in the left (Figure l). Between them is the
heart, a midline organ that tilts slightly to the left within
the chest cage. (You can feel your heart beating by placing your
fingertips under your left breast.) Although gas exchange takes
place in the lungs, the respiratory system also includes two other
components: the part of the central nervous system that controls
our breathing, and the chest bellows.
The part of the nervous system that controls
breathing is located in the mid-brain, also known as the brain
stem. It is an area more primitive than the area of the brain
responsible for thinking and motor movements, known as the brain
cortex.
Brain stem control of breathing is automatic and functions whether
we think about it or not. However, drugs or some diseases may
alter it. A relatively common cause of respiratory depression
is an overdose with narcotics or sedatives.
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