Principles of Anatomy and Physiology: The Special Senses

A set of vocabulary flashcards covering the anatomy, physiology, and development of the special senses including olfaction, gustation, vision, hearing, and equilibrium.

Olfaction

The chemical sense of smell.

Olfactory epithelium

A region in the superior part of the nasal cavity containing 10 million to 100 million receptors for smell.

Cribriform plate

Part of the ethmoid bone of the skull that the olfactory epithelium covers on its inferior surface.

Supporting cells (Olfaction)

Columnar epithelium in the mucous membrane lining the nose used for physical support, nourishment, and electrical insulation for olfactory receptor cells.

Basal stem cells

Cells that undergo mitosis to replace olfactory receptor cells.

Olfactory glands

Also known as Bowman’s glands, these produce mucus used to dissolve odor molecules for transduction.

Primary olfactory area

The region in the temporal lobe of the cerebral cortex where smell interpretation occurs.

Olfactory transduction

The binding of an odorant molecule to an olfactory receptor protein, involving chemical reactions with cyclic AMP (cAMP) to cause depolarization.

Gustation

The chemical sense of taste.

Primary Tastes

The five basic taste sensations: sour, sweet, bitter, salt, and umami (meaty, savory).

Taste buds

Structures containing receptors for taste found on the tongue, soft palate, pharynx, and epiglottis.

Vallate papillae

About 12 elevations on the tongue that each contain 100–300 taste buds.

Fungiform papillae

Elevations scattered over the tongue that contain about 5 taste buds each.

Foliate papillae

Elevations located in lateral trenches of the tongue; most of their taste buds degenerate in early childhood.

Filiform papillae

Structures covering the entire surface of the tongue that contain tactile receptors but no taste buds; they increase friction to help move food.

Visible light

Part of the electromagnetic spectrum with wavelengths from about $400$ to $700\,nm$.

Wavelength

The distance between two consecutive peaks of an electromagnetic wave.

Tarsal plate

A fold of connective tissue giving form to the eyelids, containing tarsal (Meibomian) glands that prevent eyelids from sticking together.

Conjunctiva

A thin, protective mucous membrane lining the eyelids and covering the sclera.

Lacrimal apparatus

The system responsible for producing and draining tears.

Fibrous tunic

The outer coat of the eyeball, consisting of the cornea and sclera.

Vascular tunic

The middle coat of the eyeball, consisting of the choroid, ciliary body, and iris.

Iris

The colored portion of the eyeball that regulates the amount of light entering through the pupil.

Optic disc

The point where the optic (II) nerve exits the eye, also called the blind spot.

Fovea centralis

The area of highest visual acuity located in the center of the macula lutea.

Rods

Photoreceptors in the retina used to see in dim light.

Cones

Photoreceptors in the retina that produce color vision.

Aqueous humor

A clear, watery liquid found in the anterior cavity of the eye that helps maintain shape and supplies nutrients.

Vitreous humor

A transparent, gelatinous substance in the vitreous chamber that helps maintain eye shape and keeps the retina attached to the choroid.

Astigmatism

A condition where the cornea or lens has an irregular curve, causing blurred or distorted vision.

Rhodopsin

The photopigment found specifically in rods.

Optic chiasm

A crossing point in the neural pathway for vision located after the optic (II) nerves.

External ear

The region of the ear containing the auricle (pinna), external auditory canal, and tympanic membrane (eardrum).

Auditory ossicles

The three smallest bones in the body: the malleus, incus, and stapes.

Auditory tube

Also known as the pharyngotympanic or eustachian tube, it extends from the middle ear to the nasopharynx to regulate air pressure.

Cochlea

The part of the internal ear that translates vibrations into neural impulses interpreted as sound.

Spiral organ

Also known as the organ of Corti, this structure in the cochlear duct contains hair cells that generate nerve impulses.

Static equilibrium

The maintenance of the body’s position relative to the force of gravity.

Dynamic equilibrium

The maintenance of the body’s position in response to sudden movements, such as rotational acceleration.

Vestibular apparatus

The collective organs of equilibrium, including the saccule, utricle, and semicircular canals.

Otoliths

Calcium carbonate crystals found in the otolithic membrane of the macula.

Optic vesicles

Developmental structures that arise from the ectoderm of the forebrain (prosencephalon) around 22 days after fertilization.

Otic placodes

Thickenings of surface ectoderm appearing around 22 days after fertilization that eventually form the internal ears.