The ear is the organ of hearing and balance. The ear consists of:
External or outer ear, consisting of:
Pinna or auricle. This is the outside part of the ear.
External auditory canal or tube. This is the tube that connects the outer ear to the inside or middle ear.
(also called the eardrum). The tympanic membrane divides the external ear from the middle ear.
Middle ear (tympanic cavity), consisting of:
Ossicles. These are the 3 small bones that are connected and transmit the sound waves to the inner ear. The bones are called:
Eustachian tube. A canal that links the middle ear with the back of the nose. The eustachian tube helps to equalize the pressure in the middle ear. Having the same pressure allows for the proper transfer of sound waves. The eustachian tube is lined with mucous, just like the inside of the nose and throat.
Inner ear, consisting of:
Cochlea. This contains the nerves for hearing.
Vestibule. This contains receptors for balance.
Semicircular canals. This contains receptors for balance.
The nose is the organ of smell and is part of the peripheral nervous system. The nose consists of:
External nose. A triangular-shaped projection in the center of the face.
Nostrils. These are two chambers divided by the septum.
Septum. This is made up primarily of cartilage and bone and covered by mucous membranes. The cartilage also gives shape and support to the outer part of the nose.
Nasal passages. Passages that are lined with mucous membranes and tiny hairs (cilia) that help to filter the air.
Sinuses. Four pairs of air-filled cavities that are also lined with mucous membranes.
The throat is a ring-like muscular tube that acts as the passageway for air, food, and liquid. The throat also helps in forming speech. The throat consists of:
Larynx. This houses the vocal cords and is crucial to speech and breathing. The larynx also serves as a passageway to the trachea (windpipe to the lung).
Epiglottis. This is located above the larynx and works with the larynx and vocal cords to push the food into the esophagus, therefore keeping food from entering the windpipe.
Tonsils and adenoids. These are made up of lymph tissue and are located at the back and sides of the mouth. They protect against infection, but generally have little purpose beyond childhood.