Chapter 11 – The Sensory System Vocabulary

A comprehensive set of vocabulary flashcards covering key terms from Chapter 11 on the sensory system, including structures, receptors, physiological processes, and common disorders of vision, hearing, equilibrium, taste, smell, and general senses.

Accommodation

Automatic change in the curvature of the crystalline lens so light focuses sharply on the retina

Gustation

The special sense of taste perceived by taste buds on the tongue

Refraction

Bending of light rays as they pass through the eye’s transparent parts to focus on the retina

Astigmatism

Error of refraction caused by irregular curvature of the cornea or lens, producing blurred, distorted vision

Hyperopia

Farsightedness; image focuses behind the retina so distant objects are clearer than near ones

Myopia

Nearsightedness; image focuses in front of the retina so near objects are clearer than distant ones

Presbyopia

Age-related loss of lens elasticity leading to difficulty focusing on close objects

Retina

Innermost nervous tunic of the eye containing photoreceptors (rods and cones)

Iris

Colored ring of smooth muscle that regulates pupil diameter and light entry

Sclera

Tough white fibrous outer coat of the eyeball

Aqueous Humor

Clear fluid in the anterior chamber of the eye that helps refract light and maintain intraocular pressure

Vitreous Body

Transparent, jellylike material filling the posterior eye cavity; contributes to refraction and shape

Cataract

Opacity of the crystalline lens causing progressive loss of vision

Glaucoma

Group of disorders marked by increased intraocular pressure that can damage the optic nerve

Lacrimal Apparatus

Structures that produce, drain, and distribute tears (lacrimal gland, canals, sac, duct)

Conjunctiva

Thin, transparent mucous membrane lining eyelids and covering the anterior sclera

Choroid

Middle, pigmented vascular tunic supplying blood to the retina

Lens (Crystalline Lens)

Biconvex, transparent structure that fine-tunes light refraction

Sensory Receptor

Specialized cell or dendrite that detects a specific type of stimulus

Sensory Adaptation

Decline in receptor sensitivity during continuous stimulation

Cochlea

Snail-shaped portion of inner ear that houses the spiral organ for hearing

Spiral Organ (Organ of Corti)

Receptor organ for hearing located within the cochlear duct

Auditory Tube (Eustachian Tube)

Canal connecting middle ear to nasopharynx; equalizes pressure

Ossicle

One of three small middle-ear bones (malleus, incus, stapes) that transmit vibrations

Tympanic Membrane

Eardrum; vibrates in response to sound waves

Semicircular Canal

One of three fluid-filled loops in the inner ear that detect rotational acceleration

Vestibule

Central cavity of the inner ear containing maculae for static equilibrium

Macula (in Vestibule)

Patch of hair cells embedded in otolithic membrane that senses linear acceleration

Crista

Receptor tuft of hair cells within a semicircular canal that senses rotational movement

Cupula

Gelatinous cap overlying crista hair cells in semicircular canals

Otolith

Calcium carbonate crystal in the otolithic membrane aiding static equilibrium

Kinesthesia

Sense of body movement detected by proprioceptors

Proprioceptor

Receptor in muscles, tendons, or joints that provides information on body position

Chemoreceptor

Receptor stimulated by dissolved chemicals (e.g., taste buds, olfactory neurons)

Photoreceptor

Light-sensitive receptor (rods or cones) in the retina

Thermoreceptor

Receptor responding to changes in temperature

Mechanoreceptor

Receptor stimulated by mechanical forces such as pressure or vibration

Rod Cell

Retinal photoreceptor active in dim light; produces blurred, colorless vision

Cone Cell

Retinal photoreceptor active in bright light; enables sharp, color vision

Ciliary Muscle

Ring of smooth muscle that alters lens shape during accommodation

Fovea Centralis

Depression in the macula lutea with the highest concentration of cones and sharpest vision

Convergence

Medial movement of both eyes to focus on a near object

Optic Nerve (CN II)

Cranial nerve carrying visual impulses from retina to brain

Occipital Lobe (Visual Area)

Region of cerebral cortex that interprets visual information

Equilibrium

Sense of balance maintained by vestibule and semicircular canals

Endolymph

Fluid within membranous labyrinth (cochlear duct, semicircular ducts)

Perilymph

Fluid between bony and membranous labyrinths of the inner ear

Cochlear Implant

Electronic device that bypasses damaged hair cells and directly stimulates cochlear nerve for hearing

Otitis Media

Inflammation/infection of the middle ear

Presbycusis

Age-related progressive sensorineural hearing loss

Vertigo

Abnormal sensation of spinning or movement

Analgesic

Drug that relieves pain without causing loss of consciousness

Enucleation

Surgical removal of the eyeball

Proprioception

Awareness of body position and movement

Strabismus

Misalignment of the eyes due to imbalance of extrinsic muscles

Olfaction

Sense of smell detected by olfactory receptor neurons

Taste Bud

Cluster of gustatory receptor cells within tongue papillae

Endorphin

Endogenous opioid peptide that reduces pain perception