Ch. 7.7 Special Senses Key Terms
Aqueous Humor
A watery fluid that fills the space between the cornea and the lens (anterior and posterior chambers), helping to nourish these structures and maintain pressure within the eye.
Conjunctiva
A thin, transparent membrane that covers the outer surface of the sclera (the white of the eye) and lines the inside of the eyelids.
Cornea
The transparent, dome-shaped front part of the eye that covers the iris, pupil, and anterior chamber. It's the primary structure that refracts (bends) light entering the eye.
Choroid Coat
The layer of blood vessels and connective tissue between the sclera and the retina. It provides oxygen and nourishment to the outer layers of the retina.
Iris
The colored part of the eye, a muscular diaphragm that controls the size of the pupil to regulate the amount of light reaching the retina.
Lacrimal Glands
Glands located above the outer corner of each eye that produce tears to clean, moisten, and protect the eye's surface.
Lens
A transparent structure behind the iris that changes shape (a process called accommodation) to further refract light and focus it sharply onto the retina.
Pupil
The adjustable opening at the center of the iris through which light enters the eye.
Refracts
The action of bending light, a critical function performed mainly by the cornea and the lens to focus images on the retina.
Retina
The light-sensitive layer at the back of the eye containing photoreceptor cells (rods and cones) that convert light into neural signals.
Sclera
The tough, opaque white outer layer of the eyeball that provides protection and structure.
Vitreous Humor
A transparent, gel-like substance that fills the large space between the lens and the retina (vitreous body), maintaining the shape of the eyeball
2. Auditory Canal
(External Acoustic Meatus): A passage leading from the auricle/pinna
Auricle
The visible, external part of the ear made of cartilage. It collects and funnels sound waves into the auditory canal. (Terms 3 and 14 are synonymous).
Cochlea
A spiral-shaped, bony chamber in the inner ear that contains the sensory receptors for hearing.
Eustachian Tube
A tube connecting the middle ear to the nasopharynx (the back of the nose and throat). It equalizes air pressure between the middle ear and the atmosphere.
Organ of Corti
The sensory organ for hearing, located inside the cochlea. It contains the hair cells that convert sound vibrations into nerve impulses.
Ossicles
Three tiny bones in the middle ear (malleus, incus, and stapes) that transmit and amplify sound vibrations from the tympanic membrane to the inner ear.
Pinna
The external, visible part of the ear. (Terms 3 and 14 are synonymous).
Semicircular Canals
Three fluid-filled, ring-shaped canals in the inner ear responsible for maintaining balance (equilibrium) by detecting rotational movements of the head.
Tympanic Membrane
A thin, cone-shaped membrane that separates the external ear from the middle ear. It vibrates in response to sound waves.
Vestibule
A central, bony cavity in the inner ear (between the cochlea and semicircular canals) that contains sensory organs that detect linear movements of the head and gravity, also contributing to balance.