Transcript Respiratory System Disorders

Respiratory System Disorders
Part III
Chronic Obstructive Pulmonary
Disease (COPD)
Group of disabling respiratory disorders
most commonly caused by cigarette
smoking.
 The most common COPD’s which are a
major cause of death and disability in the
US are:
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Chronic bronchitis
 Emphysema
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Common Characteristics of COPD’s
History of smoking
 Dypsnea: difficulty breathing or labored
breathing that becomes progressively
worse
 Coughing and frequent pulmonary
infections
 Hypoxia: body retains CO2 and have
respiratory acidosis and ultimately will
develop respiratory failure.
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Chronic Bronchitis
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The mucus membranes of the respiratory
passages become severely inflamed and
produce excessive amounts of mucus.
 The pooled mucus impairs ventilation and gas
exchange and increases the risk of lung
infection
 Hypoxia and carbon dioxide retention occur
early in the disease and cyanosis is common
Emphysema
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Alveoli enlarge and begin to break through the
walls of the adjacent chambers causing chronic
inflammation and fibrosis in the lungs.
Lungs become less elastic and the airways
collapse during expiration obstructing the flow
of air out of the lungs
Patients must use incredible amounts of energy
to exhale and will always appear exhausted.
Since air is retained in the lungs the oxygen
exchange is very efficient and cyanosis doesn’t
appear until late in the disease
Overinflation of the lungs will eventually lead to
a permanently expanded barrel chest.
Lung Cancer
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Accounts for 1/3 of all cancer deaths in the US
Over 90% of lung cancer patients were smokers
Most people who have lung cancer die within 1 year of
diagnosis and the 5 year survival rate is 7%
Lung cancer metastasizes (spreads) rapidly and widely
and most people are not diagnosed until they are in the
advanced stages.
Because of smoking the cleansing devices in the
respiratory tract are overwhelmed and eventually stop
working leading to the production of more mucus, which
does not get cleared because of the paralyzed cilia.
Mucus cells begin to spread widely and lose their normal
characteristics.
Types of Lung Cancer
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Squamous Cell Carcinoma:
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Adenocarcinoma:
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30-32% of all cases of lung cancer
Arises in the epithelium of the larger bronchi and
forms masses that hollow out and begin to bleed.
33-35% of all cases of lung cancer
Originates in the peripheral areas of the lung as small
nodules that develop from the bronchial glands and
alveolar cells
Small Cell Carcinoma:
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20-25% of all cases of lung cancer
Consists of lymphocyte like cells that originate in the
primary bronchi and grow aggressively in chords or
small grapelike clusters in the mediastium
Treatment for Lung cancers
The most effective treatment is to
remove the diseased part of the lung
 However, because the cancer spreads
so quickly and easily this is not always
an option.
 In most cases radiation therapy and
chemotherapy are the only options.
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Developmental Aspects of the
Respiratory System
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Fetus:
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Lungs are filled with fluid and all respiratory
exchanges are made by the placenta
At birth the fluid filled pathway is drained and the
respiratory passages fill with air.
The alveoli will inflate and begin to function in gas
exchange
The lungs do not fully inflate for approx. 2 weeks
Surfactant: Fatty molecule produced by the cuboidal
alveolar cells that lowers the surface tension of the
film of water lining the alveolar sacs preventing them
from collapse between each breath. Surfactant is not
usually present in large enough amounts until late
pregnancy 28-30 weeks.
Developmental Aspects of the
Respiratory System
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Infant Respiratory Distress Syndrome:
Occurs in infants that are borne before the
28th week of pregnancy.
 Surfactant production is inadequate causing
infants to have dypsnea within a few hours
after birth and they have to use tremendous
amounts of energy to keep reinflating the
alveoli, which collapse after each breath.
 This accounts for over 20,000 of newborn
deaths per year.
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Developmental Aspects of the
Respiratory System
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Cystic Fibrosis:
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Most common lethal genetic disease in the US
Strikes one of every 2400 white children every day
and 2 children die because of it
Causes oversecretion of the thick mucus that clogs
the respiratory passages and puts the child at risk
for fatal infections
Impairs food digestion by clogging ducts that deliver
pancreatic enzymes and bile into the small intestine
Therapy for CF is to use mucus dissolving drugs
and “clapping” the chest to loosen thick mucus and
using antibiotics to prevent infections
Developmental Aspects of the
Respiratory System
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Respiratory Rate:
Newborn: 40-80 bpm
 5 years old: 25 bpm
 Adults: 12-15 bpm
 Old Age: Starts to rise again
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The lungs will continue to mature
throughout childhood and more alveoli
are formed until young adulthood
Developmental Aspects of the
Respiratory System
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Sudden Infant Death Syndrome (SIDS)
Apparently healthy infants stop breathing
and die in their sleep
 Some cases are believed to be a problem of
the neural control of respiration and more
than 1/3 of SIDS cases appear to result
from a heart rhythm abnormality.
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Developmental Aspects of the
Respiratory System
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Asthma:
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Chronically inflamed hypersensitive bronchial
passageways that respond to many different irritants.
Signs are dypsnea, coughing and wheezing
Adulthood – Old Age:
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Chest walls become rigid and lungs lose their
elasticity resulting in a slowly decreasing ability to
fully ventilate the lungs
Vital capacity drops 1/3 by the age of 70
Blood oxygen levels decrease and sensitivity to
stimulating effects of CO2 decreases
Protective mechanisms are less efficient as well as
ciliary activity causing the lungs to be sluggish