2. The Human Respiratory System
Pharynx
Nose Larynx
Mouth Trachea
Epiglottis Lungs
Bronchus
Bronchioles
Diaphragm
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3. What is Human Respiration?
• The human respiratory system
allows one to obtain oxygen,
eliminate carbon dioxide.
• Breathing consists of two
phases, inspiration and
expiration
– Inspiration- the process of taking
in air
– Expiration- the process of
blowing out air
4. Breathing
• BREATHING
• Lungs are sealed
in pleural
membranes
inside the chest
cavity.
• At the bottom of
the cavity is a
large, flat muscle
known as the
diaphragm.
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5. Breathing
• During inhalation, the
diaphragm contracts and
the rib cage rises up.
• This expands the volume of
the chest cavity.
• The chest cavity is sealed,
so this creates a partial
vacuum inside the cavity.
• Atmospheric pressure fills
the lungs as air rushes into
the breathing passages.
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6. Breathing
• Often exhaling is a
passive event.
• When the rib cage Rib cage lowers
lowers and the
diaphragm
relaxes, pressure in
the chest cavity is
greater than
atmospheric
pressure.
• Air is pushed out of Exhalation
the lungs. Copyright Pearson Prentice Hall
