Chapter 53:
Introduction to the Respiratory System
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Anatomy of the Respiratory System
 Components
o Upper respiratory tract
o Lower respiratory tract
 Function
o Brings oxygen into the body
o Allows for the exchange of gases
o Expels carbon dioxide and other waste products
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The Respiratory Tract
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Structures of the Upper Respiratory Tract
 Nose and Nasal Cavity
 Sinuses
 Pharynx
 Larynx
 Trachea
 Bronchi
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Protective Features of the Upper
Respiratory Tract
 Hairs filter the air
 Goblet cells produce mucus to trap material
 Cilia move the trapped material toward the throat for
swallowing
 The blood supply close to the surface warms air and adds
humidity to improve gas movement and gas exchange
 The cough and sneeze reflexes clear the airways
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Cough Reflex
 The walls of the trachea and conducting bronchi are
highly sensitive to irritation.
 When receptors in the walls are stimulated, a central
nervous system reflex is initiated.
 Cough causes air to be pushed through the bronchial tree
under tremendous pressure, clearing the airway of
foreign irritant.
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Sneeze Reflex
 Initiated by receptors in the nasal cavity
 Forces foreign materials directly out of the system
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Cilia
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Layers of the Bronchial Tubes
 Cartilage
 Muscle
 Epithelial Cells
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Question #1
Please answer the following statement as true or false.
The purpose of the cough and sneeze reflexes are to clear
the airways.
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Answer to Question #1
True
Rationale: The cough and sneeze reflexes clear the
airways.
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Lower Respiratory Tract
Composed of the smallest bronchioles and the
alveoli
Considered the functional unit of the lungs
Gas exchange occurs in the alveoli - ventilation
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Components of the Respiratory
Membrane and Gas exchange
 Gas exchange occurs at alveolar level. The alveolar sac
holds the gas, allowing needed oxygen to diffuse across
the respiratory membrane. It consists of the following:
 Capillary Endothelium
 Capillary Basement Membrane
 Interstitial Space
 Alveolar Basement Membrane
 Alveolar Epithelium
 Surfactant Layer
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Structures in the Respiratory Membrane
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Process of Respiration
 Controlled through the medulla in the central nervous
system
 Depends on a balance between the sympathetic and
parasympathetic systems
 Depends on a functioning muscular system
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Controls Over the Respiratory System
 Parasympathetic nerve stimulate the diaphragm
contraction and inspiration
 Vagal stimulation leads to bronchoconstriction
 Sympathetic stimulation leads to increased rate and
depth of respiration and dilation of the bronchi to allow
free flow of air through the system
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Upper Respiratory Tract Conditions
 The Common Cold
 Seasonal Rhinitis
 Sinusitis
 Pharyngitis and Laryngitis
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Question #2
Sympathetic stimulation of the respiratory system leads
to what?
A. Decreased respiratory rate
B. Decreased depth of respirations
C. Increased respiratory rate
D. Increased perfusion of lungs
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Answer to Question #2
C. Increased respiratory rate
Rationale: Sympathetic stimulation leads to increased
rate and depth of respiration and dilation of the bronchi
to allow free flow of air through the system.
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Lower Respiratory Tract Conditions
 Atelectasis
 Pneumonia
 Bronchitis
 Bronchiectasis
 Obstructive Pulmonary Diseases- CF, COPD, and RDS
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Atelectasis
 Definition
o The collapse of once-expanded lung tissue
 Occurrence
o Result of outside pressure against the alveoli
o Most commonly occurs as a result of blockage of the
airway
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Pneumonia
 Definition
o Inflammation of the lungs
 Causes
o Bacterial or viral invasion of the tissue
o Aspiration of foreign substances into the lower
respiratory tract
 Manifestations
o Localized swelling, engorgement, and exudation of
protective sera
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Bronchitis
 Definition
o Narrowed airway during the inflammation
 Causes
o Occurs when bacteria, virus, or foreign material
infect the inner lining of the bronchi
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Bronchiectasis
 Definition
o Chronic disease characterized by dilation of bronchial
tree and chronic infection and inflammation of
bronchial passages.
 Causes
o Often underlying medical condition that makes them
more susceptible to infections
 Signs & Symptoms
o Acute infection: fever, malaise, myalgia, arthralgia,
and a purulent, productive cough(exam)
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Obstructive Pulmonary Diseases
 Asthma
 Chronic Obstructive Pulmonary Disease (COPD)
 Cystic Fibrosis
 Respiratory Distress Syndrome (RDS)
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Asthma
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Distended and Destroyed Alveoli
Versus Normal Alveoli
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Chronic Obstructive Pulmonary Disease
(COPD)
 Definition
o Permanent, chronic obstruction of airways(damaged
lung)
 Causes
o Often related to cigarette smoking/Marianna
o Emphysema and chronic bronchitis
 Manifestations
o Airflow obstruction on expiration
o Overinflated lungs and poor gas exchange
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Cystic Fibrosis(Caucasian)
 Definition
o A hereditary disease involving the exocrine glands of
the respiratory, gastrointestinal, and reproductive
tracts. CF results in the accumulation of copious
amounts of very thick secretions in the lungs.
o Causes
o Heredity
 Treatment is aimed at keeping the secretions fluid and
moving and maintaining airway patency as much as
possible.
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Respiratory distress syndrome (RDS)
 Seen in premature infants who are delivered before their
lungs have fully developed and while surfactant levels
are still very low
 Characterized by progressive loss of lung compliance and
increasing hypoxia
 Treatment: give surfacntant until they can breath on
their own.
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Question #3
An elderly Native American woman has tested positive
for tuberculosis. The woman refers to TB by another
name. What is that name?
A. Bronchiectasis
B. Emphysema
C. COPD
D. Consumption
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Answer to Question #3
D. Consumption
Rationale: Tuberculosis is a bacterial infection. Once
known as consumption, this disease has been responsible
for many respiratory deaths throughout the centuries.
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