Anatomy of the Respiratory System
Respiration
Respiration is the act of breathing:
Respiratory system
The respiratory system is made up of the organs included in the exchange of oxygen
and carbon dioxide. These are the parts:
The upper respiratory tract is made up of the:
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Nose
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Nasal cavity
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Sinuses
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Larynx
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Trachea
The lower respiratory tract is made up of the:
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Lungs
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Bronchi and bronchioles
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Air sacs (alveoli)

Lungs
The lungs take in oxygen. Your body's cells need oxygen to live and carry out their
normal functions. The lungs also get rid of carbon dioxide, a waste product of the
cells.
The lungs are a pair of cone-shaped organs made up of spongy, pinkish-gray tissue.
They take up most of the space in the chest (thorax).
The lungs are surrounded by a membrane (pleura).
The lungs are separated from each other by the mediastinum, an area that contains
the:
The right lung has 3 sections, called lobes. The left lung has 2 lobes. When you breathe
in:
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Air enters your body through your nose or mouth.
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Air then travels down the throat through the larynx and trachea.
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Air goes into the lungs through tubes called main-stem bronchi.
One main-stem bronchus leads to the right lung and one to the left lung:
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In the lungs, the main-stem bronchi divide into smaller bronchi.
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The smaller bronchi divide into even smaller tubes (bronchioles).
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Bronchioles end in tiny air sacs (alveoli) where the exchange of oxygen and carbon
dioxide occurs.
You then breathe out carbon dioxide.