Diplomate, Board Certification of Emergency Medicine
Chairman, Department of Emergency Medicine Ma'ayenei
Hayeshua Hospital
The lungs are amazing organs. They are responsible for
bringing oxygen to all the cells in our body and for
releasing carbon dioxide which is a by-product of cell
metabolism. They have amazing absorption capabilities:
medications given by liquids or aerosols are absorbed into
the blood stream in seconds.
The lungs are reached through a hard tube called the
trachea, which is located in the throat. It has a special
covering called an epiglottis which assures that food and
drink does not find its way into the lungs, and then it
branches off in the upper chest to the bronchi, which enter
the lungs. As the bronchi branch off to become smaller and
smaller tubes, they become more elastic. They also develop
little hairs that brush away dust and particles. Finally,
they arrive at little areas where little blood cells and the
air tubes meet -- this area is actually semicircular and
covered by a gooey substance called surfactant. This shape
and this substance help to maximize gas exchange.
Surfactant is crucial. It can be lost when the lungs fill
with fluid -- such as in drowning and that makes
resuscitations very difficult. It is often absent in
premature infants. Until recently, premature infants had no
opportunity for survival because their lungs could not
absorb oxygen. Now that surfactant is available for use by
physicians, infants as young as 23 weeks can survive.
Everything in the lung is finely tuned. Trouble occurs, when
the blood vessels or the airways close off or when the cough
and cleaning mechanisms are impaired. An example of the
latter is a stroke patient who cannot close his epiglottis
to prevent food from entering and causing pneumonia. People
who are intubated, that is on a respirator, also do poorly
occasionally because of this.
An example of the first two is in smoking where many
breathing units are lost, so there is less ability to bring
in enough oxygen. That is one reason why smokers have such
shortness of breath when they try to exert themselves. On
the other hand, in athletes this is very well developed; the
heart responds by increasing the blood flow to the organs
being exerted and to the lungs. The lungs respond by opening
all the units for the rush of blood that is coming in.
Similarly, the body makes adjustments for people who live at
high altitudes, where there is less blood in the atmosphere.
In this case, the body also manufactures more red blood
cells so that the less oxygen that is available is not
wasted. Next week we'll talk about problems that can occur.
Write me in care of the Yated.
A message from Glaxo, the sponsor of this column. It
has been a while since we reminded you about the anti-
migraine medications called Imitrex and Naramig. They are
extremely effective and are tailored just for migraines;
they are not general pain relievers. If you are a migraine
sufferer, please give these a try.
