Ch. 7.7 Special Senses Key Terms
Aqueous humor
Aqueous humor: Clear, watery fluid that fills the space between the cornea and iris. It helps maintain the forward curvature of the eyeball and refracts light rays.
Auditory canal
Auditory canal (External auditory meatus): The canal or tube in the outer ear that funnels sound waves to the tympanic membrane.
Auricle
Auricle (or Pinna): The visible, elastic cartilage part of the outer ear that collects sound waves.
Choroid coat
Choroid coat: The middle, vascular layer of the eye that contains many blood vessels and nourishes the eye.
Cochlea
Cochlea: A structure in the inner ear, shaped like a snail's shell, that contains the organ of Corti (the receptor for sound waves).
Conjunctiva
Conjunctiva: A mucous membrane that lines the eyelids and covers the front of the eye for protection and lubrication.
Cornea
Cornea: The circular, transparent front part of the sclera that allows light rays to enter the eye.
Eustachian tube
Eustachian tube: A tube connecting the middle ear to the pharynx (throat) that helps equalize air pressure on both sides of the tympanic membrane.
Iris
Iris: The colored portion of the eye, which contains muscles that control the size of the pupil.
Lacrimal glands
Lacrimal glands: Glands that produce tears to moisten and cleanse the eye.
Lens
Lens: A circular structure located behind the pupil that refracts (bends) light rays to focus them on the retina.
Organ of Corti
Organ of Corti: The receptor of sound waves, composed of delicate hairlike cells, located within the cochlea.
Ossicles
Ossicles: The three small bones in the middle ear (malleus, incus, and stapes) that transmit sound waves.
Pinna
Pinna (or Auricle): The visible, elastic cartilage part of the outer ear that collects sound waves.
Pupil
Pupil: The opening in the center of the iris that regulates the amount of light entering the eye.
Refracts
Refracts: The action of bending light rays, performed by the cornea, aqueous humor, lens, and vitreous humor to focus light on the retina.
Retina
Retina: The innermost, light-sensitive layer of the eye containing photoreceptor nerve cells (rods and cones) that transmit impulses to the optic nerve.
Sclera
Sclera: The tough, white, outermost connective tissue layer of the eye that maintains its shape.
Semicircular canals
Semicircular canals: Structures in the inner ear containing liquid and hairlike cells that send impulses to the cerebellum to help maintain balance and equilibrium.
Tympanic membrane
Tympanic membrane (Eardrum): Separates the outer ear from the middle ear and vibrates when sound waves hit it.
Vestibule
Vestibule: The entrance section of the inner ear, leading to the cochlea and semicircular canals.
Vitreous humor
Vitreous humor: A jellylike substance that fills the area behind the lens and helps maintain the shape of the eyeball while refracting light rays.