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mechanism of gas exchange.


Diffusion of gases across a semi-permeable membrane.

Respiratory System

Site of gas exchange.

Large enough

Needs to be ______ for the exchange of oxygene and carbon dioxide to occur at a rate to meet the needs of the organism.


Needs to be ______ so the oxygene and carbon dioxide can diffuse across the cell membrane.


The respiratory surface must be ______ so diffusion of gases can occur rapidly.


Conducts air into the nasal pasages

Moistens the air

The mucus in the nose ______ and the numerous capillaires that line the nose warms the air. This is to protect the delicate tisse of the lungs.


Connects the mouth and the nasal cavity.

There are other openings found here such as the ______

1) Esopagus
2) Trachea
3) Oral Cavity
4) Eustachian Tubes


The ______ is a flap-like structure that covers the trachea when swallowing food.


Also called the voice box.


Also called the wind pipe.

Semicircle cartilage rings

It contains ______ to pervent the trachea from collapsing.

Ciliated cells

It contains ______ that secrete mucus to trap foreign particles. The cilia propel the material to the nose and throat.


Branches off the trachea into each lung.


Finer tubes branching off the bronchi inside each lung.


Tiny sac-like structure found at the end of each bronchiole.

This is where the ______ inside the lung.

Oxygene and carbon dioxide are exchanged.


Each alveolus is surrounded by ______.

300 million alveoli have a hanging surface of


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