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| Emphysema |
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Contents
1. Introduction
2. The structure and function of the lungs
3. Emphysema as a lung disease
4. Conclusion
5. Bibliography
Introduction
The lungs belong to the organs, which are vitally important
for normal functioning of the whole human organism. Unfortunately,
as the human being in general, the lungs are not perfect and
often they may be affected by some disease. Among the most
serious diseases linked to the lungs problems is emphysema.
Taking into consideration the importance of the lungs and
their significance for the human organism it is necessary
to clearly realize what the normal structure and functioning
of the lungs is, what the symptoms of emphysema are, what
the entity of this disease is and, finally, what measures
can be undertaken to prevent the development of this disease.
In fact all these questions will be answered in terms of this
paper.
The structure and function of the lungs
The lungs have quite a complicated structure. They are located
in the thoracic cavity and protected by the bony structure
of the rib cage. They are enclosed by a double-walled sac
called pleura. The inner layer of the sac, which is called
visceral pleura, adheres tightly to the lungs and the outer
layer, which is called parietal pleura, is attached to the
wall of the chest cavity. The two layers are separated by
a thin space called the pleural cavity that is filled with
the pleural fluid. Due to this the inner and outer layers
slide over each other and they cannot be separated easily.
It is worthy of noting that the left lung is smaller than
the right one to give way to the heart.
The lungs attach to the heart and trachea through the structures
that are called the ‘roots of the lungs’. The
roots of the lungs include the bronchi, pulmonary vessels,
bronchial vessels, lymphatic vessels and nerves. The lungs
are divided into lobes by horizontal and oblique fissures.
The right lung has three lobes and the left one has two. A
unique feature of the left lung is the cardiac notch to create
the lingula of the left lung.
The lungs are connected to the upper airway by trachea and
bronchi. The trachea runs down the neck and divides into left
and right bronchi behind the sternal angle. The right main
bronchus is shorter than left and runs more runs more vertically.
As a result, it is more common to aspirate foreign objects
into the right lung. The bronchi enter the lung and branch
out to form the bronchial tree. The bronchi divide into smaller
bronchioles and the latter terminate in the alveoli. An alveolus
is composed of respiratory tissue and is the site of the gas
exchange in the lung.
The blood is supplied to the lungs from two sources: the pulmonary
vessels and the bronchial vessels. The bronchial vessels support
the nonrespiratory tissue while the pulmonary vessels provide
support to the respiratory tissue.
The pulmonary arteries carry deoxygenated blood that has returned
to the heart from the venous system to the lungs to be reoxygenated.
The pulmonary veins carry oxygenated blood back to the heart
to go to the arterial system. The right and left pulmonary
arteries arise from the pulmonary trunk and carry ‘venous’
blood to their respective lungs while the pulmonary veins,
two on each side, carry ‘arterial’ blood to the
left atrium of the heart. The bronchial arteries that supply
nonrespiratory tissue of the lungs arise from different sources.
The left bronchial artery comes off thoracic aorta, while
the right bronchial artery a variable source.
As for the normal functioning of the lungs, it should be pointed
out that the main function is to transport oxygen from the
atmosphere into the bloodstream and excrete carbon dioxide
from the bloodstream into the atmosphere. Air enters and leaves
the lungs through the bronchi and bronchioles and than it
is redistributed to all tissues through the circulatory system.
Air is brought in the organism through the airways, i.e. the
nose, the pharynx, the larynx, the trachea, the bronchi and
bronchioles, and the terminal branches of the respiratory
tree. Than within the alveoli the gas exchange occurs, as
it has been just described above. It should be pointed out
that the drawing and expulsion of air is driven by a large
muscle, known as the diaphragm, which drive ventilation by
periodically altering the intra-thoracic volume and pressure.
By increasing volume and decreasing pressure, air is sucked
into airways, and by reducing volume and increasing pressure,
the reverse occurs. During normal breathing, expiration is
passive and no muscles are contracted.
Emphysema as a lung disease
Unfortunately, there are many diseases that affect lungs normal
functioning. One of such diseases is emphysema. In scientific
terms, emphysema is defined as permanent destructive enlargement
of the airspaces distal to the terminal bronchioles without
obvious fibrosis. Basically this disease is characterized
by elasticity of the lung tissue, destruction of structures
supporting the alveoli, and destruction of capillaries feeding
the alveoli. As a result the process of breathing, and gas
exchange in particular becomes quite problematic for the small
airways collapse during expiration, leading to an obstructive
form of lung disease, when air is trapped in the lungs. The
main features of the disease are the shortness of breath on
exertion, particularly when climbing stairs or incline and
later at rest, hyperventilation and expanded chest. As emphysema
progresses, clubbing of the fingers may be observed, that
is a feature of longstanding hypoxia.
Sometimes emphysema patients are referred to as ‘pink
puffers’ because emphysema sufferers may hyperventilate
to maintain adequate blood oxygen levels. Hyperventilation
explains why emphysema patients do not appear to be cyanotic
like chronic bronchitis sufferers often do. This is why they
are ‘pink’ puffers, due to adequate oxygen levels
in the blood.
Consequently it is obvious that it is necessary to help he
patients suffering from emphysema as soon as possible but
what is even more important is to provide a proper diagnosis
in time in order to start treatment at the beginning stage
of the disease when patients have more opportunities to recover
from it.
Traditionally diagnosis is made by spirometry, lung function
testing, including diffusion testing. In addition other investigations
might be used, for instance, X-ray, high resolution spiral
chest CT-scan, bronchoscopy (especially when other lung disease
is suspected, including malignancy), blood test, pulse oxymetry
and arterial blood gas sampling.
In fact emphysema is irreversible degenerative condition that
needs proper and thorough treatment. Speaking about the treatment
it is necessary to say that the most effective measure that
can be taken to slow the progression of emphysema is for the
patient to stop smoking and avoid all exposure to cigarette
smoke and lung irritants. Pulmonary rehabilitation may be
very helpful to optimise the patient’s quality of life
and teach the patient how to actively manage his or her care.
It is treated by supporting the breathing with anticholinergics,
bronchodilators and inhale or oral steroid medication, and
supplemental oxygen as required. Treating patient’s
other conditions including gastric reflux and allergies may
also help the patient’s lung function. Supplement oxygen
used as prescribed, i.e. 20+ hours/day, is the only non-surgical
treatment which has been shown to prolong life in emphysema
patients. Nonetheless, other medications are currently being
researched and probably in the future there would be found
some plausible and effective treatment. Also there are lightweight
portable oxygen systems which allow patients increasing mobility
and patients can fly, cruise and work while using supplemental
oxygen.
However, surgical methods seem to be the most effective treatment
of emphysema patients. For instance, lung volume reduction
surgery (LVRS) can improve the quality of life for carefully
selected patients. It can be done by several different methods,
some of which are minimally invasive. The only ‘cure’
for emphysema is a lung transplant, although not many patients
are strong enough physically to survive the surgery. The combination
of the patient’s age, oxygen deprivation and the side
effects of the medications used to treat emphysema cause damage
to the kidneys, heart and other bodily organs. Transplants
also require the patient to take an anti-rejection drug regimen
which suppresses immunities and creates new medical issues.
Conclusion
Thus, taking into account all above mentioned, it is possible
to conclude that emphysema is a serious chronic disease which
affects the lungs and influences the proper functioning the
whole organism and needs an emergent treatment. Unfortunately,
non-surgical treatments are ineffective as a rule and supplemental
oxygen is the only effective non-surgical treatment. In fact
the most effective is the surgical treatment but in the same
time it is the most dangerous one since not all patients can
survive it. Consequently, it may be said that it is necessary
to find alternative ways of treatment, desirably non-surgical
ones that could really improve the emphysema patient’s
state and cure them effectively but it is only a future perspective
while nowadays the problem still remains unsolved and the
patients has either to undergone the surgical treatment or
hopefully wait, if they physically can, for better and safer
treatment.
Bibliography:
1. Johnson, D.R. Respiratory System. New York: Touchstone,
2001.
2. Livingston, G. L. Emphysema: Diagnosis and Treatment. LA:
McGraw Hill, 2002.
3. Thompson, K. Introductory Anatomy. New York: Routledge,
2000.
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