Glossary

Anvil: One of the three bones of the middle ear that helps transmit sound waves from the outer ear to the cochlea. It is also called the Incus.
Auditory Nerve: Nerve that transmits signals from the cochlea to the brain.
Cochlea: Shaped llike a snail's shell, this organ of the inner ear helps transmit hearing signals to the brain.
Decibel: A unit for measuring the loudness of a sound.
Ear Canal: Tunnel in the middle ear that funnels sound from the outer ear to the eardrum.
Eardrum: Membrane separating the outer ear from the inner ear. It is aso called the Tympanic Membrane.
Hammer: One of the three bones of the middle ear that helps transmit sound waves from the outer ear to the cochlea. It is also called the Malleus.
Semicircular Canals: Three tubes in the inner ear that control balance.
Stirrup: One of the three bones of the middle ear that helps transmit sound waves from the outer ear to the cochlea. It is also called the Stapes.

Cortex: The pale gray surface layer of the brain in which information is processed.
Sense: A body organ or collection of organs that informs us of some aspect of the outside world such as odors (smell).
Thalamus: Small area in the brain through which most of the information received from the sense organs passes.

Color Blind
When someone cannot make out the difference between colors.

Cones
They are receptors that are sensitive to all the colors in the visible spectrum of light.

Cornea
The clear, tough covering over the iris and pupil that helps protect the eye from damage.

Farsighted
Being able to see distant things clearly, but close things look blurred.

Iris
Muscle that controls the amount of light that enters the eye. It is found between the cornea and the lens.

Lens
A clear, flexible structure that adjusts the eyes focus, allowing us to see objects both near and far. It is responsible for about 20 percent of our focusing.

Nearsighted
Only able to see things close by, and anything farther away is blurred.

Optic Nerve
The bundle of nerve fibers that carry information from the ritina to the brain.

Pupil
A black spot in the middle of the eye that looks like a small blak hole.

Retina
The layer of light sensitive cells lining the inside of your eye that detects images focused on the back of your eye. It is connected to the brain by the optic nerve.

Rods
They are receptors that are sensitive to light and dark.

Sclera
The white part of the eye around the iris.

Vitreous Humor
Clear, jellylike fluid found in the back portion of the eye. Maintains shape of the eye.

Mucous
Sticky, watery material secreted from special glands that protects and lubricates delicate surfaces including the inside of the nose.

Nasal Cavity
Space in the skull, behind the nose, through which inhaled air passes on its way to the lungs.

Nerve Impulse
Tiny electrical signals that carry their information in a coded form like tiny bursts of electricity inside a computer.

Nostrils
Either of the external openings of the nose.

Olfactory Organs
The organs of smell which are positioned in the top of the nasal cavity.

Pheremones
Chemical messengers which are produced in perspiration and cause a response in the smelling organs.

Smell Receptors
The structures that respond to stimuli in smell and causes a nerve impulse to be generated.

Turbinates
thins shelves of the bone in the nasal cavity which guide the air and direct its flow.

Chemical
Any substance that can change when joined or mixed with another.

Papillae
Bumps on the tongue that include groups of cells that sense taste.

Taste Buds
Parts of the tongue with sensors to taste food.

Tongue
The muscle in the mouth that aids in tasting food.

Braille
A special alphabet for blind people made up of patterns of raised dots, and each pattern stands for a letter of the alphabet.

Dermis
The skins inner layer.

Epidermis
The outer layer of the skin.

Touch Receptors
The structures that respond to touch stimuli and causes a nerve impulse to be generated.