Medical Terminology, Chapter 16: Special Senses (Anatomy & Physiology-Eye, Ear)(pharmacology)

ossicles: malleus or hammer, incus or anvil & stapes or stirrups

3 bones collectively called: ossicles. conducts sound by transmitting sound waves thru bone to the stapes which hits the oval window of the cochlea. middle ear conducts sound waves (thru bone). within tympanic cavity & form a connection between tympanic membrane & cochlea. part of middle ear.

eustachian tube

Also called Auditory tube, pharyngotympanic tube. connect middle ear to pharynx. equalizes pressure on outer & inner surfaces of eardrum. Allows fluid/mucus to drain from ear to nasopharynx.

refractive

ability to bend light rays as they pass from one medium to another.

accommodation (Acc)

adjustment of eye for various distances so images fall on retina of eye. Acc.

ophthalmic moisturizers

administered topically and used to facilitate ophthalmoscopic exam in gonioscopy & ophthalmoscopy.

tympanic membrane

also called: tympanum or eardrum. is a flat, membranous structure drawn over end of ear canal. sound waves enter ear canal strike against tympanic membrane, causing it to vibrate. vibrations cause movement of 3 smallest bones of the body: collectively called ossicles (malleus or hammer, incus or anvil & stapes or stirrups). part of outer ear. myring/o, tympan/o

humor

any fluid or semifluid of the body. The eye has 2--aqueous humor in the anterior/posterior chambers and vitreous humor in the vitreous chamber.

posterior chamber

behind the lens. filled with transparent watery fluid called aqueous humor. similar to cerebrospinal fluid. fluid drains and flows freely between anterior & posterior chambers of the eyes.

blind spot

center of optic disc. referred to as blind spot, because has no rods or cones for vision.

acuity

clearness or sharpness of a sensory function

outer or external ear

conducts sound waves thru air, middle ear(thru bone) and inner ear (thru fluid). series of transmissions generates impulses that are sent to brain & interpreted as sound.

cochlea

conducts sound waves thru fluid. snail-shaped structure filled w/fluid called perilymph. inner surfaces lined with highly sensitive hearing structure called organ of Corti. devoted to hearing.

decongestants

constrict small arterioles of the eye, decreasing redness and relieving conjunctival congestion.

vestibular system

control balance & eye movements. contains semicircular canals, vestibule, utricle & saccule.

6 extraocular muscles of eye

control movement of eye. superior, inferior, lateral & medial rectus muscles & superior & inferior oblique muscles. coordinate eyes to move in a synchronized manner.

the lens

crystalline body that is convex. sharpens focus of light on retina thru accommodation (Acc) where curvature of lens changes along with pupil to enable eye to adjust to near & distant objects. phac/o

antiglaucoma agents/drugs

decrease aqueous humor production by constricting the pupil (pupill/o) to open the angle (goni/o) between the iris (irid/o) & cornea(corne/o)

mydriatics

drugs that disrupt parasympathetic nerve supply to the eye or stimulate the sympathetic nervous system causing pupil to dilate. used to dilate pupil to treat inflammatory conditions or preparation for internal eye exam.

ophthalmic anesthesia

drugs that locally block pain signals at the eye. numb's eyes before surgery or tests.

auricle or pinna

earlobe--collects waves traveling thru air & channels them to external auditory canal also called ear canal. part of outer ear.

endolymph

fluid inside membraneous labyrinth of ear. also called Scarpa's fluid.

perilymph

fluid that closely resembles spinal fluid but found in cochlea

aqueous humor

fluids (humors) of the eye. found in anterior & posterior chambers of eye. tissue fluid so it supplies nutrients & oxygen to lens & cornea & some cells of retina & carries away metabolic wastes. fluid flows freely back & forth between the two chambers.

The eye

globe shaped organ composed of 3 distinct tunics or layers: fibrous, vascular (uvea) & sensory tunic.

Organ of Corti

highly sensitive hearing structure lining inner surface of cochlea and contains tiny nerve endings called hair cells.

anterior chamber

in front of the lens. filled with transparent watery fluid called aqueous humor. similar to cerebrospinal fluid. fluid drains and flows freely between anterior & posterior chambers of the eyes. the anterior chamber serves similar function to subarachnoid space around the brain & spinal cord.

retina

in sensory tunic--innermost layer of eye. retina is double layered. primary function is image formation. consists of thin, outer pigmented layer lying over choroid & thick inner nervous layer or visual portion. It lies in the posterior portion of the eye. responsible for reception & transmission of visual impulses to brain. Has two types of visual receptors: rods (black & white images & peripheral images) & cones (color images) (photo sensitive receptor cells). more cones than rods. blood vessels can be seen directly here.

cones

in sensory tunic--innermost layer of eyeball. part of retina. a visual receptor that functions in bright light & produce color vision.

rods

in sensory tunic--innermost layer of eyeball. part of retina. a visual receptor that functions in dim light & produce black & white vision. concentrated on outer edges of retina & used in peripheral vision.

macula

in sensory tunic--innermost layer of eyeball. part of retina. central portion of retina & highly sensitive.

fovea

in sensory tunic--innermost layer of eyeball. part of retina. in center of macula. when eye focuses on object, light rays from that object directed to fovea. fovea composed of only cones that lie close to each other, provides greatest acuity for color vision.

antibiotics

inhibit growth of microorganisms that infect the eye

canthi (singular canthus)

inner edge of eyes where tears collect.

sensory tunic

innermost layer of eyeball. has retina.

semicircular canals

interconnected tubes located in the inner ear as part of the labyrinth of the inner ear.The three canals are: 1. horizontal semicircular canal (also known as the lateral semicircular canal), 2. superior semicircular canal (also known as the anterior semicircular canal), 3. posterior semicircular canal (also known as the inferior semicircular canal). the canals response to rotational movement (angular acceleration)

labyrinth

intricate communicating passages of inner ear system consisting of fluid-filled tubes, sacs and nerves that connect structures to brain. labyrinth rests inside temporal bones, includes cochlear system (for hearing) & vestibular system (balance & eye movements).

vitreous humor

jellylike substance that fills interior chamber (vitreous chamber) of eye. contributes to intraocular pressure (IOP) & helps prevent eyeball from collapsing. holds retina flushed against the internal portion of eyeball. refracts light. This humor, lens & aqueous humor are refractive structures of eye. isn't continuously produced. blindness can occur if injury to eye causes fluid to escape.

vestibule

joins cochlea and semicircular canals.

vitreous chamber/posterior cavity

largest area in the eye. located between lens & retina. filled with transparent jelly-like substance called vitreous humor that maintains the eyeball's shape & makes up 4/5 of the eye's size.

tunic

layer or coat of tissue. also called membrane layer. The eye has 3-fibrous, vascular (uvea) & sensory tunics.

refractive structures

lens, aqueous & vitreous humor focus light rays sharply on retina. if one of these structures doesn't function properly, vision is impaired.

wax emulsifiers

loosen and help remove impacted cerumen(ear wax).

oval window

membrane-covered opening on external surface of cochlea. provides place for attachment of stapes. movement of ossicles in middle ear causes stapes to exert gentle pumping action against oval window. pumping action forces perilymph to disturb hair cells, generating impulses that are transmitted to brain by way of auditory nerve, where they are interpreted as sound. part of middle ear.

vascular tunic

middle layer of eye. also known as UVEA. consists of choroid, iris, ciliary body & pupil.

eyelids

movable folds of skin with eyelashes that protect front of eye.

utricle

or utriculus --meaning "leather bag"), along with the saccule, is one of two otolith organs in the inner ear. utricle and saccule are parts of the balancing apparatus (membranous labyrinth) within the vestibule of the bony labyrinth (small oval chamber). These use small stones and a viscous fluid to stimulate hair cells to detect motion and orientation. The utricle detects linear accelerations and head-tilts in the horizontal plane.

fibrous tunic

outermost layer of eye. protective coat for sensitive structures beneath. Includes: sclera, cornea & conjunctiva. cornea is transparent, allowing light to enter interior of eye.

conjunctiva

part of fibrous tunic (outermost structure of eye). part of adnexa (supporting structure) of eye. Conjunctiva covers outer surface of eye, inner surface of eyelids & cornea. produces watery, clear mucus for eyelids to slide easily across surface of eye with each blink. mucus also traps articles that enters eyes. conjunctiv/o

sclera

part of fibrous tunic-outermost layer of eyeball. (sclera or white of eye) provides strength, shape & structure to eye. protects inner structures of the eye from injury. as it passes in front of eye, it bulges forward to become cornea.

cornea

part of fibrous tunic-outermost layer of eyeball. as sclera passes in front of eye, it bulges forward to become the transparent, domed cornea. cornea doesn't contain capillaries & rely on eye fluids for nourishment. curved surface to bend light to focus an image on the retina.

choroid

part of vascular (uvea) tunic-middle layer of eye. (provides blood supply for eyes with its many blood vessels). has pigmented cells that prevent extraneous light from entering eye & blurring images. opening inside choroid allows optic nerve to enter eye (posteriorly from brain). anterior portion of choroid contains two modified structures: Iris & ciliary body.

ciliary body

part of vascular (uvea) tunic-middle layer of eye. ciliary body made up of smooth ciliary muscle. controls lens & produces aqueous humor. as ciliary muscle contracts--makes lens round and improves focus of near objects. As ciliary muscle relax--makes lens flat and improves focus of far objects. these changes in shape allow eye to focus on an image, a process called accommodation (Acc). suspensory ligaments hold it in place & attach it to the lens.

Iris

part of vascular (uvea) tunic-middle layer of eyeball. Extension of the choroid. A ring of pigmented tissue that protrudes into the cavity of the eyeball. Iris (colored, contractile membrane w/perforated center called pupil). Iris controls the pupil to regulate amount of light passing thru pupil to interior of eye. pigmentation of iris determines eye color.

pupil

part of vascular (uvea) tunic-middle layer of eyeball. Iris controls the pupil to make it constrict or dilate. as light increase, pupil constricts, as light decreases, pupil dilates.

lacrimal canals

pinpoint openings where tears pass thru to mucous membranes that line inside nasal cavity.

optic disc

point where nerve fibers from retina converge to form optic nerve where it extends to visual center of brain. optic nerve transmits nerve impulses from eye to brain. brain interprets impulses and tells us what we see. blood vessels enter eye thru optic disc. where blind spot is at center.

otic analgesics

provide temporary relief from pain and inflammation assoc. with otic disorders. for otitis media, otitis externa and swimmer's ear. some otic analgesics are also wax emulsifiers.

ophthalmic decongestant

relieves itching and minor irritation of allergies.

photopigment/visual pigment

rods & cones contain this chemical. as light strikes it, chemical change occurs that stimulates rods & cones. chemical changes produce impulses transmitted thru optic nerve to brain where it's interpreted as vision.

saccule

saccule and utricle) react to steady (static) pressures (gravitational forces). Hair cells within these structures are covered by a gelatinous cap in which are embedded small granular particles of calcium carbonate, called otoliths. utricle and saccule within the vestibule, respond to changes in the position of the head with respect to gravity (linear acceleration). The saccule detects linear accelerations and head-tilts in the vertical plane.

The ear

sense receptor organ for hearing & equilibrium. consists of 3 major sections. outer or external ear, middle ear or tympanic cavity & inner ear or labyrinth. hearing is function of cochlea. equilibrium is function of semicircular canals & vestibule.

external auditory canal or ear canal

slender tube lined w/glands that produce waxy secretion called cerumen. part of outer ear.

Specific Sensations

smell, taste, vision, hearing and equilibrium. Each connected to a specific organ or structure in the body.

moisturizers

soothe dry eyes due to environmental irritants & allergens.

equilibrium

state of balance that is managed by the semicircular canals of the inner ear.

opaque

substance or surface that neither transmits nor allows passage of light

lacrimal glands

superior & outer edge of each eye. produce tears that bathe & lubricate eyes.

adnexa

tissues or structures in body adjacent to or near a related structure.

ophthalmic antibiotics

topical ointments and solutions to treat bacterial eye infections such as conjunctivitis (pink eye)

General Sensations

touch, pressure, pain & temperature. not identified with a specific site of the body.

antiemetics

treat and prevent nausea, vomiting, dizziness, and vertigo by reducing sensitivity of inner ear to motion or inhibiting stimuli from reaching brain

canal of Schlemm

unusual venous channel. junction at iris & cornea. small opening where aqueous humor drains from eye. if aqueous humor fails to drain from eye at rate it is produced, pressure develops & causes compression to the optic nerve & retina & may cause glaucoma.

cerumen

waxy secretion produced by glands in external auditory canal or ear canal. its stickiness traps foreign particles & prevents them from entering deeper areas of canal.