CHAPTER 7-THE RESPIRATORY SYSTEM
I. THE RESPIRATORY SYSTEM is involved in respiration (gas exchange).
A. This system plays a key role in exchanging oxygen and waste gases between the
atmosphere and the body and its cells.
B. External Respiration-also known as breathing, is involved in exchanging air between
the body and the outside environment. Oxygen is carried into the lungs through inhalation
and carbon dioxide is eliminated from the body via exhalation.
C. Internal Respiration-occurs when oxygen is carried to body cells and carbon dioxide is
removed from body cells.
D. The respiratory system is composed of the respiratory tract, the lungs and muscles that
move air in and out of the lungs.
II. THE RESPIRATORY TRACT-also known as the airway, provides a route for air to
enter/exit the lungs. Parts of the Respiratory Tract:
A. Nose-air is inhaled through the nostrils (openings) of the nose.
1. Functions of the nose include: moistening, filtering and warming the incoming
air.
2. Structurally, the nose is formed externally by the nasal bones and is divided
internally by the nasal septum.
3. Cilia line the nasal cavity and function by filtering debris in the incoming air.
4. Internally, the nasal cavity is covered by a mucous membrane.
5. Paranasal Sinuses surround the nasal cavity and function by warming incoming
air. What is a sinus?
6. Olfactory neurons-in the nasal cavity, these are receptors for the sense of smell.
B. The Pharynx-Throat-serves as a passageway for both food and air. It is divided into 3
sections:
1. The Nasopharynx-lies above the soft palate or posterior portion of the roof of the
mouth. The pharyngeal tonsils (adenoids) are located here and are involved in
immune responses.
2. The Oropharynx-posterior to the oral cavity, plays a role in swallowing. The
Palatine tonsils are located here, they are involved in immune responses.
3. The Laryngopharynx-point where the throat divides to form the esophagus (site
for food passage) and the Larynx (voice box) through which air passes to reach
the trachea. Food is kept out of the larynx by a flap of cartilage known as the
epiglottis. What is the Heimlich Maneuver?
C. The Larynx-box composed of several cartilages. The Thyroid cartilage (Adam’s Apple)
is the largest of the cartilages associated with the larynx.
1. Internally, the larynx contains the vocal folds which are composed of cartilage.
2. Air if forced over the vocal folds to produce sound.
D. The Trachea-windpipe, connects the larynx to the right and left bronchi. The trachea is
composed of a series of cartilage rings and it serves as a passageway for air. The
bronchi carry air directly into the lungs where they branch into smaller and smaller tubes
known as bronchioles.
III. THE LUNGS-paired, located in the thoracic cavity.
A. Externally, the lungs are covered by a double layered membrane known as the pleura.
1. The outer membrane is the parietal pleura which lines the thoracic cavity.
The membrane that attaches directly to the lungs is known as the visceral pleura.
The pleural cavity is the space between these two membrane layers and it is filled
with fluid to prevent friction between the membranes.
B. The top of each lung is referred to as the apex and the lower portion of the lung is known
as the base. The hilum is a slit on each lung where blood vessels, bronchi and lymphatic
vessels enter the lung.
C. Each lung is subdivided into lobes. The right lung has 3 lobes (superior lobe, middle lobe,
inferior lobe), whereas, the left lung only has 2 lobes (superior lobe and inferior lobe).
1. Humans can function with one or more lobes removed.
D. Alveoli-small, thin-walled air sacs in the lungs. Terminal bronchioles bring air to the
alveoli.
1. The alveoli are covered by the pulmonary capillaries.
2. Oxygen diffuses from the alveoli into the pulmonary capillaries and carbon
dioxide diffuses from the capillaries into the alveoli.
IV. MUSCLES ASSOCIATED WITH BREATHING
A. The Diaphragm-muscle that separates the thoracic cavity from the abdominal cavity.
1. This muscle functions by changing pressure levels in the thoracic cavity which
allows for inspiration and expiration.
B. The Intercostal Muscles-assist in enlarging the chest cavity which allows air to flow into
the lungs (inspiration).
V. MEDICAL WORD ELEMENTS-pages 172-175.
VI. ILLNESSES
A. Chronic Obstructive Pulmonary Disease
1. Asthma
2. Chronic Bronchitis
3. Emphysema
B. Influenza
C. Pleural Effusions
D. Tuberculosis
E. Pneumonia
F. Cystic Fibrosis
G. Acute Respiratory Distress Syndrome
H. Lung Cancer
VII. DISEASES/CONDITIONS/PROCEDURES-pages 181-192
VIII. PHARMACOLOGY-pages 192-193.
IX. Diagnostic Terms of the Respiratory System
A. Auscultation-listening to the lungs with a stethoscope.
B. Percussion-tapping over the lung region to see if the lungs are clear of sputum.
1. Sputum can be observed for color. For example, pus in sputum causes it to be
yellow or green which indicates infection; whereas, blood in sputum may indicate
tuberculosis.
C. Spirometer-test machine that measures the lungs’ volume and capacity.
1. Pulmonary Function Tests-measured with a spirometer; are used to monitor the
mechanics of breathing.
D. Bronchography-provides a radiological image of the lungs.
E. Endoscopy-the use of a viewing tube to observe a body cavity or space.
1. Bronchoscope-used to examine and clear the bronchi and bronchioles.
F. Laboratory Tests
1. Throat cultures-used to diagnose strep infections.
2. Sputum sample-used to identify specific infectious agents.
3. Arterial blood gases (ABG)-used to measure oxygen and carbon dioxide levels in
the blood.
4. Sweat test-measures salt in sweat. Is used to test for Cystic fibrosis.