Respiratory System
• The process of exchanging
gases between the atmosphere
and body cells is called
respiration.
Events of respiration
• Exchange of gases between air in
the lungs and the blood is called
external respiration
• Gas exchange between blood and
body cells is called internal resp.
Pathway of air in the body
•
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•
•
•
•
•
•
Nose or mouth
Nasal cavity or oral cavity
Pharynx
• The alveoli are
Larynx
the site for gas
Trachea
exchange in the
Bronchi
body
Bronchioles
Alveoli
Epiglottis
Diaphragm
Breathing Mechanism
• Remember: Diffusion is a
passive process, no energy is
required.
• Normal atmospheric pressure
is 760 mm Hg
Inspiration
• The diaphragm contracts (flattens) and
moves downward.
• Thoracic cavity enlarges; alveoli increase
in diameter
• The pressure within the lungs (and
alveoli) falls about 2mm Hg below normal
(758 mm Hg)
• Air is sucked into the lungs bc of
negative pressure
Expiration
• Diaphragm relaxes (curved)
• Thoracic cavity decreases in size and
alveoli diameter decreases
• Lung (and alveoli) pressure increases to
about 1 mm Hg above normal (761 mm
Hg)
• Air is forced out of lungs (passive
process)
Smoking
• Smoking destroys the movement of
cilia in the resp. system
• This allows dirt and debris to enter the
resp. system and mucus builds up in
the nasal cavity
• this build up results in smokers’ cough
(an effort to manually breakup the
accumulated mucus)
Smoking
• Smokers’ cough leads to chronic
bronchitis (infection of the bronchiole
tubes)
• Mucus production increases, the
bronchioles thicken (less
diameter)more difficult to breathe
• Bronchioles lose elasticity and cannot
adjust to pressure changes
Smoking
• Air pressure increases enough to burst
alveoli- this condition is called
emphysema
• With emphysema coughing worsens
along with fatigue and wheezing
• Emphysema can progress to cancer
• 80% of all lung cancer is caused from
smoking
• 13% of those with lung cancer do not live
past 5 years
Total lung capacity
• the vital capacity plus the residual
volume
• average = 5800ml
• varies with age, sex, and body
size
Respiratory Volumes
• One inspiration followed by
expiration is a respiratory cycle
• Tidal Volume-the amount of air that
enters or leaves the lungs during a
normal resting respiration (about
500 ml)
Respiratory Volumes
• During forced maximal inspiration
(deep breathing) additional
quantities of air enter the lungs; this
is called inspiratory reserve volume.
• This can equal about 3,000 ml
Respiratory Volumes
• During maximal forced ex(it)piration,
about 1100ml of additional air can be
expelled from the lungs; this is the
expiratory reserve volume.
• This leaves about 1200 ml of air in the
lungs at all times – this is called
residual volume
Vital capacity
• The total of the inspiratory reserve
volume, the tidal volume, and the
expiratory reserve volume is the vital
capacity (max in, normal, max out)
• The adult average is about 4,600 ml.
• This is the maximum amount of air a
person can exhale after they have
taken the deepest breath possible
Inspiratory capacity
• The tidal volume plus the
inspiratory reserve volume.
• This is the maximum amount of
air a person can inhale
• average – 3500 ml
Functional residual capacity
• the expiratory reserve volume plus
the residual volume
• equals the amount of air left in the
lungs after normal expiration
• average = 2300ml
Total lung capacity
• A spirometer is used to measure
lung capacity
• Lung capacity measurements can
be used as an initial diagnostic tool
for emphysema, pneumonia, lung
cancer, and asthma
Gas Transport
• Oxygen is carried in the blood
bound to the hemoglobin in RBC
• Each hemoglobin molecule can
combine with only four oxygen
atoms
• Hypoxia – oxygen deficiency
Alveoli
Hemoglobin
Respiratory
Disorders
Pneumonia
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an infection of the lungs, which can be caused by
a variety of microorganisms, including viruses,
bacteria, fungi, and parasites
causes inflammation of the lungs
symptoms: fever, chills, cough, unusually rapid
breathing, breathing with grunting or wheezing
sounds, chest pain
treated with antibiotics, antiviral meds
Tiger Woods w pneumonia
Bronchitis

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viral infection of the bronchial tree
bronchioles swell and mucus (thick fluid)
forms inside them, making it hard to
breathe
symptoms: coughing up mucus and
wheezing
treated with asthma medicines to reduce
swelling and ease breathing
Bronchitis
Emphysema
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chronic lung disease usually caused by
smoking
damage to the alveoli
symptoms: Shortness of breath, barrelshaped chest, wheezing, fatigue, losing
weight without trying
treatment: no cure, but symptoms can be
eased with supplemental oxygen and other
meds
Asthma

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chronic respiratory disease causing airway
inflammation; the airways in the lungs are overly
sensitive to certain triggers
linked to allergies, heredity, environment, weight
symptoms: attacks of wheezing, coughing, chest
constriction & labored breathing
treated with meds such as inhaled steroids/antiinflammatory
Tuberculosis
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disease caused by bacteria that attack the lungs
bacteria destroy lung tissue and can actually create
a hole in the lung
symptoms: a bad cough, pain in the chest,
coughing up blood, fever, fatigue, chills
treated with antibiotics
latent TB (bacteria in body but not active causes
small bump on test) vs. active TB (bacteria actively
attacking lung tissue)
No bump means on TB skin test means you are
negative for TB
Tuberculosis
Cystic Fibrosis

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
hereditary, recessive, caused by a gene/protein
defect
chloride can’t be transported out of cells, so water
diffuses indries out mucus, causing it to clog
affect organs
affects lungs (more infections)& pancreas
(prevents digestive enzymes from reaching
intestines, causing decreased nutrient absorption)
treatments: antibiotics for infections, exercises to
remove mucus from lungs, digestive enzymes
mixed into foods
Cystic Fibrosis
Lung Cancer

Cigarette smoking causes an estimated 443,000
deaths each year, including approximately 49,400
deaths due to exposure to secondhand smoke.

Lung cancer is the leading cause of cancer death
among both men and women in the United States,
and 90 percent of lung cancer deaths among men
and approximately 80 percent of lung cancer deaths
among women are due to smoking.
Smoking causes many other types of cancer, including cancers of
the throat, mouth, nasal cavity, esophagus, stomach, pancreas,
kidney, bladder, and cervix, and acute myeloid leukemia.
People who smoke are up to six times more likely to suffer a heart
attack than nonsmokers, and the risk increases with the number of
cigarettes smoked. Smoking also causes most cases of chronic
lung disease.
In 2009, approximately 20.6 percent of U.S. adults were cigarette
smokers.
Nearly 20 percent of high school students smoke cigarettes.
The last 2 slides are copied from the www.cancer.gov website