Sensory Organs: Anatomy, Mechanics, and Pathologies of the Tongue, Eye, and Ear

Comprehensive vocabulary flashcards covering anatomical terminology, physiological mechanisms, optical and auditory principles, and pathological conditions of the human tongue, eye, and ear.

Tongue

A highly mobile muscular organ consisting mainly of skeletal muscle covered by a moist mucous membrane that alters shape, position, and direction.

Apex (Tip of the Tongue)

The anterior part of the tongue that manipulates food, detects taste, and is essential for speech articulation.

Dorsum

The upper surface of the tongue textured by numerous small projections called papillae.

Ventral Surface

The underside of the tongue characterized by a thinner mucosal covering and visible blood vessels.

Root of the Tongue

The posterior base that anchors the tongue to throat structures and is critical for swallowing.

Filiform Papillae

Small, numerous papillae with a rough surface covering the majority of the dorsum that provide friction to grip and manipulate food, lacking taste buds.

Fungiform Papillae

Mushroom-shaped papillae concentrated at the tip and lateral sides of the tongue that contain taste buds to detect taste chemicals.

Foliate Papillae

Folds or ridges located on the posterolateral borders of the tongue that contain taste buds to detect taste chemicals.

Circumvallate Papillae

Large, curved papillae arranged in a V-shaped row toward the back of the tongue that house taste buds.

Salivary Amylase

A digestive enzyme present in saliva that begins the chemical breakdown of starch into simpler carbohydrates in the mouth.

Bolus

A soft, rounded mass of chewed food mixed with saliva, prepared by the tongue and teeth ready to be swallowed.

Deglutition

The swallowing mechanism initiated when the muscular tongue presses against the roof of the mouth to propel the bolus backward into the pharynx.

Cornea

The transparent front surface of the eye that refracts light entering the eye.

Sclera

The tough, white outer protective layer covering the eye.

Iris

The pigmented, coloured muscular ring that controls the diameter and size of the pupil.

Pupil

The central opening of the iris through which light passes into the interior of the eye.

Eye Lens

A transparent, convex optical structure that fine-focuses light rays onto the retina.

Choroid

A vascular layer situated between the sclera and retina that supplies blood and absorbs stray light to prevent internal reflection.

Retina

The light-sensitive inner coat of the eye containing photoreceptor cells: rods for dim-light vision and cones for colour and fine detail.

Fovea

A specialized central depression on the retina providing the highest visual acuity.

Optic Nerve

The sensory cranial nerve that transmits electrical nerve impulses from the retina to the brain.

Accommodation

The reflex process by which ciliary muscles and suspensory ligaments adjust the curvature and refractive power of the lens to focus on objects at varying distances.

Pupillary Reflex

An autonomic reflex controlling light intake where circular muscles contract to constrict the pupil in bright light and radial muscles contract to dilate it in dim light.

Convex Lens

An optical lens thicker in the middle that converges parallel light rays; used to correct hypermetropia (long-sightedness).

Concave Lens

An optical lens thinner in the middle that diverges parallel light rays; used to correct myopia (short-sightedness).

Myopia

Short-sightedness; a condition where parallel rays focus in front of the retina due to an elongated eyeball or excessive refractive power, causing distant objects to appear blurred.

Hypermetropia

Long-sightedness; a condition where light rays focus behind the retina due to a shortened eyeball or weak refraction, causing near objects to appear blurred.

Glaucoma

A sight defect characterized by abnormally high fluid pressure buildup within the aqueous humour, resulting in compression and degeneration of optic nerve fibers.

Cataracts

An optical condition where the crystalline lens becomes cloudy or opaque, obstructing light transmission and blurring vision.

Astigmatism

A refractive defect caused by an irregular curvature of the cornea or lens, creating multiple uneven focal points and distorted vision.

Pinna (Auricle)

The visible cartilaginous outer ear structure that gathers sound waves from the environment, directs them into the ear canal, and aids sound localization.

Cerumen

Ear wax secreted within the external auditory canal that traps dust, deters microbes, prevents infection, and keeps the canal moist.

Tympanic Membrane (Eardrum)

A thin, stretched membrane separating the outer and middle ear that vibrates upon contact with sound waves, converting airborne vibrations into mechanical vibrations.

Auditory Ossicles

Three tiny bones located in the air-filled middle ear cavity—the malleus, incus, and stapes—that transmit and amplify mechanical sound vibrations.

Malleus

The hammer-shaped middle ear ossicle attached directly to the tympanic membrane that receives its vibrations.

Incus

The anvil-shaped middle ear bone that receives vibrations from the malleus and conveys them to the stapes.

Stapes

The stirrup-shaped bone, and smallest bone in the human body, that pushes sound vibrations against the oval window of the inner ear.

Eustachian Tube

A canal linking the middle ear cavity to the pharynx (throat) that equalizes air pressure across both sides of the eardrum.

Cochlea

A fluid-filled, snail-shaped chamber in the inner ear housing the Organ of Corti where fluid motion is converted into electrical nerve impulses.

Organ of Corti

The sensory receptor organ within the cochlea containing specialized hair cells that generate nerve impulses when bent by fluid movement.

Vestibule

An inner ear structure containing the utricle and saccule responsible for sensing static head position and linear movements.

Semicircular Canals

Three fluid-filled looped tubes oriented along the X, Y, and Z axes that detect rotational head acceleration and spinning movements.

Otitis Media

An inflammatory middle ear infection caused by bacteria, viruses, or Eustachian tube obstruction, leading to otalgia, fever, and hearing impairment.

Vertigo

A vestibular balance disorder producing a false sensation of spinning and nausea, triggered by inner ear infection, imbalance, or displaced canal crystals.

Tinnitus

The perception of internal ringing, buzzing, or hissing sounds in the ear caused by noise exposure, acoustic damage, or stress.