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Chapter 22 Gas Exchange
THE HUMAN RESPIRATORY SYSTEM
The respiratory system functions to allow oxygen to diffuse into the blood and release carbon dioxide. Blood contains a protein molecule called hemoglobin that binds oxygen and helps transport it and carbon dioxide
Oxygen is used by cells during cellular respiration.
© 2012 Pearson Education, Inc.
22.6 In mammals, branching tubes convey air to lungs located in the chest cavity
The diaphragm
– separates the abdominal cavity from the thoracic cavity and
– helps ventilate the lungs.
In mammals, air is inhaled through the nostrils into the nasal cavity. Air is
– filtered by hairs and mucus surfaces,
– warmed and humidified, and
– sampled for odors.
© 2012 Pearson Education, Inc.
22.6 In mammals, branching tubes convey air to lungs located in the chest cavity
From the nasal cavity, air next passes
– to the pharynx,
– then larynx, past the vocal cords,
– into the trachea, held open by cartilage rings,
– into the paired bronchi,
– into bronchioles, and finally
– to the alveoli, grapelike clusters of air sacs, where gas exchange occurs.
© 2012 Pearson Education, Inc.
Figure 22.6A
Nasal cavity
Pharynx
Larynx
(Esophagus)
Trachea
Right lung
Bronchus
Bronchiole
Diaphragm
(Heart)
Bloodcapillaries
Bronchiole
Alveoli
CO2O2
Oxygen-poorblood
From the heart
To the heart
Oxygen-richbloodLeft lung
Figure 22.UN03
a.
b.c.
d.
e.
f.
h.
g.
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