Chapter 17 - Special Senses (Eye, Ear, Olfaction, Gustation, Touch) - Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering the major structures and concepts in the chapter about the eye, ear, olfaction, gustation, and touch. Each card provides a term and a concise definition.

Auricle (Pinna)

The external, visible part of the ear that collects sound and directs it toward the external acoustic canal.

External Acoustic Canal (External Auditory Canal)

The passage that carries sound waves from the auricle to the tympanic membrane; lined with glands producing ear wax.

Tympanic Membrane (Eardrum)

Thin membrane that vibrates when struck by sound waves, transmitting energy to the auditory ossicles.

Auditory Ossicles

Three small bones (malleus, incus, stapes) that transmit vibrations from the tympanic membrane to the inner ear.

Malleus (Hammer)

Ossicle attached to the tympanic membrane; transmits vibrations to the incus.

Incus (Anvil)

Middle ossicle that transmits vibrations from the malleus to the stapes.

Stapes (Stirrup)

Ossicle that transmits vibrations to the oval window of the inner ear.

Oval Window

Membrane-covered opening that transmits vibrations from the stapes into the inner ear fluids.

Round Window

Membrane that allows displacement of cochlear fluids in response to stapes motion.

Auditory (Eustachian) Tube

Tube that connects the middle ear to the nasopharynx to equalize pressure on both sides of the tympanic membrane.

External Ear

The outer portion of the ear responsible for collecting sound and directing it inward.

Middle Ear

Air-filled cavity containing the auditory ossicles and connected to the nasopharynx via the Eustachian tube.

Inner Ear

Contains sensory organs for hearing and balance; includes the cochlea and vestibular apparatus.

Tensor Tympani

Muscle that stiffens the tympanic membrane to protect hearing from loud sounds.

Stapedius

Muscle that dampens vibrations of the stapes to protect the inner ear.

Cochlea

Snail-shaped organ in the inner ear that contains hair cells for hearing.

Organ of Corti

Structure within the cochlea containing hair cells that transduce sound into neural signals.

Hair Cells

Sensory receptors of the cochlea (inner and outer) that convert mechanical vibrations into nerve impulses.

Basilar Membrane

Supportive membrane whose vibration encodes sound frequency in the cochlea.

Tectorial Membrane

Gelatinous membrane overlaying hair cells in the cochlea; interacts with the hair stereocilia.

Cochlear Duct (Scala Media)

Endolymph-filled duct housing the organ of Corti and hair cells.

Scala Vestibuli

Perilymph-filled chamber that begins at the oval window and surrounds the cochlear duct.

Scala Tympani

Perilymph-filled chamber that ends at the round window.

Perilymph

Fluid between the bony and membranous labyrinth in the inner ear; similar to CSF.

Endolymph

Fluid within the membranous labyrinth containing high potassium; essential for hair cell function.

Semicircular Canals

Three canals that detect rotational movement and angular acceleration of the head.

Ampulla

Widened region at the base of each semicircular duct that contains the hair cells of the crista.

Crista Ampullaris

Sensory organ in the ampulla containing hair cells and supporting cells.

Cupula

Gelatinous structure in the semicircular duct that deflects hair cells when endolymph moves.

Utricle

Otolithic organ that detects horizontal acceleration; contains maculae and statoliths.

Saccule

Otolithic organ that detects vertical acceleration; contains maculae and statoliths.

Macula

Sensory patch in the utricle and saccule that houses hair cells and statoliths.

Otoliths (Statoconia)

Calcium carbonate crystals in the otolithic membrane that signal head position via gravity.

Vestibule

Central chamber of the inner ear that houses the utricle and saccule; involved in balance.

Vestibulocochlear Nerve (CN VIII)

Cranial nerve that carries auditory and vestibular information to the brain.

Fibrous Tunic

Outermost eye layer consisting of the sclera and cornea; provides protection and shape.

Sclera

The white of the eye; protects the eye and provides attachment for the extraocular muscles.

Cornea

Transparent anterior layer that refracts light into the eye.

Limbus

Border area between the cornea and sclera where vessels and nerves are abundant.

Vascular Tunic (Uvea)

Middle eye layer; includes the iris, ciliary body, and choroid; controls light entry and lens shape.

Iris

Colored part of the eye; smooth muscle that changes pupil size to regulate light entry.

Pupil

Central opening of the iris through which light enters the eye.

Ciliary Body

Structure that anchors the lens, produces aqueous humor, and contains muscles that adjust lens shape.

Choroid

Vascular layer between the sclera and retina; nourishes the retina.

Ora Serrata

Junction between the retina and the ciliary body.

Retina (Neural Tunic)

Innermost eye layer containing photoreceptors; converts light into neural signals.

Pigmented Part of Retina

Outer retinal layer that absorbs excess light and supports photoreceptors.

Neural Part of Retina

Inner retinal layer where visual signals are processed; contains photoreceptors, bipolar, and ganglion cells.

Rods

Photoreceptors for low-light vision; do not detect color.

Cones

Photoreceptors for color vision and high-acuity vision in bright light.

Macula Lutea

Central retina area rich in cones responsible for high-acuity vision.

Fovea Centralis

Center of the macula; highest cone density and sharpest vision.

Optic Disc (Blind Spot)

Site where the optic nerve leaves the retina; no photoreceptors are present.

Optic Nerve (CN II)

Carries visual information from the retina to the brain.

Optic Chiasm

Point where some optic nerve fibers cross to the opposite hemisphere.

Lateral Geniculate Nucleus

Thalamic relay center that processes visual information before it reaches the visual cortex.

Visual Cortex

Occipital lobe region that processes visual information from the eyes.

Canal of Schlemm

Drainage channel for aqueous humor that helps regulate intraocular pressure.

Aqueous Humor

Clear fluid in the anterior and posterior chambers; nourishes the cornea and lens.

Vitreous Humor

Gel-like substance filling the posterior cavity that maintains eye shape.

Lens

Transparent structure that focuses light onto the retina; its shape is altered by the ciliary muscles.

Suspensory Ligaments

Fibers that connect the lens to the ciliary body and help adjust lens shape.

Ciliary Muscles

Muscles that change lens shape during accommodation.

Anterior Chamber

Cavity between the cornea and the iris containing aqueous humor.

Posterior Chamber

Cavity between the iris and the ciliary body containing aqueous humor.

Accommodation

Adjustment of the lens shape to focus on near or distant objects.

Emmetropia

Normal vision where images are focused on the retina.

Myopia (Nearsightedness)

Eyes focus images in front of the retina; corrected with diverging lenses.

Hyperopia (Farsightedness)

Eyes focus images behind the retina; corrected with converging lenses.

Astigmatism

irregular curvature of the cornea or lens causing distorted vision.

Photoreceptors

Rods and cones that detect light and initiate vision.

Rhodopsin

Light-sensitive pigment in rod cells composed of opsin and retinal.

Opsin

Protein component of rhodopsin that changes shape when activated by light.

Retinal

Light-absorbing molecule bound to opsin in rhodopsin; changes configuration with light.

Pupillary Constriction (Sphincter Pupillae)

Muscle that decreases pupil diameter to limit light entry.

Pupillary Dilation (Dilator Pupillae)

Muscle that increases pupil diameter to allow more light in.

Lacrimal Apparatus

System that produces, distributes, and drains tears; includes glands, ducts, puncta, canaliculi, lacrimal sac, and nasolacrimal duct.

Lacrimal Gland

Tear-producing gland located above the eye; tears contain lysozyme for antibacterial protection.

Lacrimal Ducts

Passages that transport tears from the lacrimal gland toward the eye surface.

Lacrimal Puncta

Small openings on the eyelid margin that drain tears onto the ocular surface.

Lacrimal Canaliculi

Canals that carry tears from the puncta to the lacrimal sac.

Lacrimal Sac

Reservoir that collects tears before they drain into the nasolacrimal duct.

Nasolacrimal Duct

Duct that drains tears from the lacrimal sac into the nasal cavity.

Conjunctiva

Mucous membrane lining the eyelids and covering the sclera; palpebral and ocular parts.

Palpebral Conjunctiva

Inner surface of the eyelids; lines the eyelids themselves.

Ocular (Bulbar) Conjunctiva

Covers the anterior surface of the eyeball.

Conjunctivitis

Pinkeye; irritation or infection of the conjunctival surface.

Eyelashes

Hairs on the eyelids that help protect the eye from debris.

Palpebral Fissure

The opening between the upper and lower eyelids.

Medial/Lateral Canthus

Medial and lateral corners where the eyelids meet.

Olfactory Epithelium

Specialized epithelium in the nasal cavity containing olfactory receptor cells.

Olfactory Receptor Cells

Sensory neurons that detect odorants and initiate smell sensation.

Olfactory Bulb

Expanded neural structure at the end of the olfactory tract that processes smell.

Olfactory Tract

Bundle of neurons that carries olfactory information from receptors to brain.

Cribriform Plate

Part of the ethmoid bone with foramina for olfactory nerves to pass.

Odorant Binding Proteins

Molecules that bind airborne odorants and help initiate olfactory signaling.

Olfactory Nerve (CN I)

Nerve that transmits smell information from the nasal cavity to the brain.

Gustation (Taste)

Sense involving taste receptors located in taste buds on the tongue and other areas.

Taste Buds

Structures containing gustatory receptor cells that detect tastants.

Gustatory Cells

Taste receptor cells within a taste bud.