Special Senses: Hearing and Vision

A complete set of vocabulary flashcards covering key anatomical structures, physiological processes, pathways, and disorders for hearing, balance, and vision based on the lecture notes.

Auricle

The external ear structure, also known as the pinna, that opens into the external auditory canal to collect sound waves and direct them toward the external auditory canal.

External Auditory Canal

The canal that transmits collected sound waves from the auricle to the tympanic membrane.

Ceruminous Glands

Glands located in the external ear canal that produce cerumen.

Tympanic Membrane

A thin membrane, also known as the eardrum, that separates the external ear from the middle ear and vibrates in response to sound waves.

Middle Ear

An air-filled cavity containing the three auditory ossicles that transmit vibrations from the eardrum to the inner ear.

Auditory Ossicles

Three small bones (malleus, incus, stapes) forming a flexible, bony bridge in the middle ear that transmits vibrations from the tympanic membrane to the oval window.

Malleus

The auditory ossicle attached to the medial surface of the tympanic membrane.

Incus

The middle auditory ossicle connecting the malleus to the stapes.

Stapes

The innermost auditory ossicle whose base is seated in the oval window surrounded by a flexible ligament.

Auditory Tube

A canal opening into the pharynx that enables air pressure to be equalized between the middle ear and outside air.

Oval Window

A membrane separating the middle ear from the inner ear that receives vibrations from the base of the stapes.

Bony Labyrinth

The hard outer structure of the inner ear divided into the cochlea, vestibule, and semicircular canals.

Membranous Labyrinth

A smaller set of membranous tunnels and chambers located within the bony labyrinth and filled with endolymph.

Endolymph

The fluid contained inside the membranous labyrinth of the inner ear.

Perilymph

The fluid filling the space between the bony labyrinth and the membranous labyrinth.

Cochlea

A spiral-shaped passage in the inner ear leading from the oval window that contains sensory receptors for hearing and balance.

Cochlear Duct

A passage within the cochlea filled with fluid that vibrates when sound waves strike.

Acoustic Nerves

Nerves that transmit sensory information from the ear to the brain and send signals to muscles throughout the body to maintain equilibrium.

Air Conduction

The process where sound waves enter the pinna, travel down the auditory canal, and strike the tympanic membrane.

Bone Conduction

The process where auditory ossicles conduct sound waves through the middle ear as the tympanic membrane vibrates.

Sensorineural Conduction

The process where sound waves reach the inner ear via the oval window, are received by inner ear structures, and are relayed to the brain.

Static Equilibrium

Sensory evaluation of the head position relative to gravity, associated with the vestibule.

Dynamic Equilibrium

Sensory evaluation of changes in the direction and rate of head movement, associated with the semicircular canals.

Maculae

Sensory structures located in the vestibule consisting of hair cells with microvilli embedded in a gelatinous mass containing otoliths.

Tinnitus

An ear disorder characterized by ringing in the ears.

Presbycusis

Age-related sensorineural hearing loss.

Ophthalmologist

A medical specialist who specializes in diagnosing and treating diseases and disorders of the eye.

Optometrist

A vision specialist who measures the accuracy of vision to determine if corrective lenses or eyeglasses are needed.

Oculodexter

Medical term referring to the right eye.

Oculosinister

Medical term referring to the left eye.

Oculouterque

Medical term referring to both eyes.

Extraocular

Term meaning outside the eyeball.

Intraocular

Term meaning inside the eyeball.

Vision

The process by which the eyes detect light and convert it into electrical signals transmitted to the brain to be interpreted as images.

Eyebrows

External structures that prevent sweat, water, and debris from falling into the eyes and provide protection from sunlight glare.

Eyelids

Protective structures that open and close rapidly to protect the eye from foreign objects and keep it lubricated.

Eyelashes

Hairs along the eyelid margin that trigger an immediate blink reflex to protect the eye and reduce airflow across the eye surface.

Lacrimal Apparatus

The system responsible for producing, distributing, and draining tears to maintain eye moisture and protect against irritation.

Conjunctiva

A thin, transparent membrane lining the inside of the eyelids and covering the white part of the eye (sclera).

Fibrous Tunic

The outer layer of the eye consisting of the sclera and cornea.

Vascular Tunic

The middle layer of the eye consisting of the choroid, ciliary body, and iris.

Nervous Tunic

The innermost layer of the eye composed of the retina.

Sclera

The tough, opaque outer layer of the eye covering approximately $\frac{5}{6}$ of its surface that maintains eye shape, protects internal structures, and attaches extrinsic muscles.

Cornea

The transparent, dome-shaped outermost layer covering the iris, pupil, and anterior chamber that refracts light and protects the eye.

Iris

The colored part of the eye located between the cornea and lens containing the sphincter pupillae and dilator pupillae muscles to regulate pupil size.

Pupil

The black circular opening in the center of the iris that acts as an aperture allowing light to enter the eye.

Pupillary Reflex

An automatic response controlled by the autonomic nervous system that changes pupil size in response to light intensity.

Lens

A transparent, flexible, biconvex structure behind the iris held by zonules, composed of water and crystallins, that focuses light onto the retina.

Crystallins

Specialized protein fibers that make up the structure of the lens along with water.

Retina

A thin, light-sensitive layer of tissue located at the back of the eye that converts light into neural signals.

Ganglion Cell Layer

The layer of the retina containing cell bodies of ganglion cells, which send visual information to the brain via the optic nerve.

Bipolar Cell Layer

The layer of the retina that transmits signals from the photoreceptors to the ganglion cells.

Rods

Photoreceptor cells in the retina that are highly sensitive to light but do not detect color.

Cones

Photoreceptor cells in the retina responsible for color vision and high visual acuity.

Retinal Pigment Epithelium (RPE)

A layer of pigmented cells supporting photoreceptors by absorbing excess light, providing nutrients, and participating in the visual cycle.

Macula Lutea

A yellow area located in the center of the retina.

Fovea Centralis

A pit in the middle of the macula lutea with a high concentration of cones where color vision and acuity are highest.

Optic Disc

The point where the optic nerve exits the eye, also known as the blind spot due to a lack of photoreceptors.

Optic Chiasm

The region at the base of the brain where optic nerves from both eyes meet and partially cross over.

Optic Tract

The visual pathway continuing after the optic chiasm that carries signals to the lateral geniculate nucleus (LGN) of the thalamus.

Extrinsic Eye Muscles

Six major muscles (four recti and two obliques) responsible for the movement of the eyeball.

Anterior Chamber

The cavity in the front of the eye between the cornea and iris filled with aqueous humor.

Posterior Chamber

The cavity in the eye between the iris and lens filled with aqueous humor.

Vitreous Chamber

The large cavity behind the lens filled with vitreous humor.

Nystagmus

An eye condition characterized by involuntary, repetitive movements of the eyes.

Diplopia

A visual disorder commonly known as double vision.

Strabismus

A condition in which the eyes are misaligned and do not focus on the same point simultaneously.

Myopia

A common refractive error known as nearsightedness where light focuses in front of the retina.

Presbyopia

Age-related loss of lens flexibility resulting in difficulty focusing on close objects.