sense organs: the ye & the ear. the ear combining forms for the ear: ot/o, aur/o, auricul/o ...

Sense Organs: Sense Organs: The ye & the EarThe ye & the Ear

THE EARTHE EARCombining Forms for the ear:

ot/o, aur/o, auricul/o

Two functions of the ear:HearingEquilibrium (balance)

Three separate regions of the ear:Outer earMiddle earInner ear

1. Auricle (pinna) – projecting flap where sound waves enter

2. Auditory canal leads from pinna to middle ear

3. Produces cerumen (ear wax) which lubricates and protects the ear

OUTER EAROUTER EARAuricle

Auditory canal

Sound waves travel through auditory canal and strike membrane between outer & middle ear.

This membrane is called the tympanic membrane or eardrum. The tympanic membrane vibrates with sound waves and moves 3 small bones in the middle ear. These small bones are called ossicles.

MIDDLE EARMIDDLE EAR

Tympanic Membrane

The three small bones also have individual names:

1. Malleus – the TM moves this bone first

2. Incus – vibration moves this bone next

3. Stapes (staped/o) – vibrates last and touches the next membrane called the oval window


Tympanic Membrane

MalleusIncus

Stapes

Oval windowOval window separates the middle ear from the inner ear.

Eustachian TubeEustachian Tube (salping/o) leads from the middle ear to pharynx

• Is normally closed, except when swallowing.

• Aids in prevention of damage to eardrum and shock to middle and inner ear when air pressure is greater in the middle ear than in atmospheric air.


Tympanic Membrane

Malleus Incus

StapesOval Window Eustachian Tube

Also called the labyrinth because of it’s circular, maze-like structure.

Cochlea (cochle/o) leads from the oval window; small, snail shaped; has two parts:1. Auditory Liquids

a. Perilymphb. Endolymph

c. Vibrations travel through

these liquids2. Organ of Corti – sensitive auditory receptor; are tiny hair like calls that receive vibrations from auditory liquids and relay sound waves to auditory nerve fibers.

INNER EARINNER EAR

Cochlea

Auditory Nerve Fibers – receive sound vibrations from the auditory liquids and end in the auditory center of the cerebral cortex of the brain where impulses are heard and interpreted.

Vestibule – connects the cochlea to 3 semicircular canals for balance.

Semicircular canals (Organ for Equilibrium) – contain endolymph & hair cells that fluctuate in response to movement of the head; nerve fibers send message to brain & brain sends message to muscles to maintain balance.“-saccule” & “–utricle” are membranous sacs

INNER EARINNER EAR

Cochlea

Auditory Nerve FibersVestibule

Semicircular Canals

Figure 17-1. Pattern of events in the stimulation of a sense organ.

SEQUENCE OF EVENTS IN SEQUENCE OF EVENTS IN STIMULATION OF SENSE STIMULATION OF SENSE

ORGANORGAN

Figure 17-21. Pathway of sound vibrations from the outer ear to the brain (cerebral cortex).

PATHWAY OF SOUND PATHWAY OF SOUND VIBRATIONSVIBRATIONS

1. Conduction – caused by impairment of the middle ear ossicles and membranes that transmit sound waves into cochlea.

2. Nerve – caused by impairment of the cochlea or auditory nerve

TYPES OF DEAFNESSTYPES OF DEAFNESS

Figure 17-25. Ear thermometer using a tympanic membrane thermometer.

AURAL AURAL TEMPERATURETEMPERATURE

acous/o = HEARINGHEARING acoustic = audi/o = SENSE OF HEARING SENSE OF HEARING audiometer = audit/o = HEARINGHEARING auditory = -cusis = HEARINGHEARING presbycusis = -otia = EAR CONDITIONEAR CONDITION macrotia = LARGE LARGE

EARSEARS

microtia = SMALL EARSSMALL EARS

ABBREVIATIONSAD = RIGHT EARRIGHT EARAS = LEFT EARLEFT EARAU = BOTH EARSBOTH EARSENT = EAR, NOSE, & THROATEAR, NOSE, & THROATEENT = EYES, EARS, NOSE, & THROATEYES, EARS, NOSE, & THROAT

COMBINING FORMS & COMBINING FORMS & ABBREVIATIONSABBREVIATIONS

1. Otitis Media – inflammation of middle ear, caused by infection (staphylococcus or streptococcus bacteria)

2. Tinnitus – tinkling sound in the ear; can be ringing, buzzing, whistling, etc….

3. Vertigo – sensation of irregular or whirling motion of oneself or external objects; equilibrium and balance are affected.

PATHOLOGICAL CONDTIONSPATHOLOGICAL CONDTIONS

(A) Healthy tympanic membrane. (B) Tympanic membrane with

cholesteatoma. (C) Tympanic membrane with

acute otitis media. (D) Myringotomy with

tympanostomy tube.

TYMPANIC MEMBRANETYMPANIC MEMBRANE

4. Meniere’s Disease – disorder of labyrinth marked by elevated endolymph pressure. Symptoms include tinnitus, vertigo, and loss of hearing. Cause is unknown. Bedrest, sedation and drugs for nausea and vertigo are commonly given.

5. Otosclerosis – bone growth around oval window and stapes leading to fixation (stiffening) causing improper conduction of vibration. Corrected with stapedectomy and replacement by prosthesis.

PATHOLOGICAL CONDTIONSPATHOLOGICAL CONDTIONS

(A)Stapedectomy. Using microsurgical technique and a laser, the stapes bone is removed from the middle ear.

(B)A prosthetic device (wire, Teflon, or metal) is placed into the incus and attached to a hole in the oval window.

TREATMENT FOR A FORM OF TREATMENT FOR A FORM OF CONDUCTION HEARING LOSSCONDUCTION HEARING LOSS

Otomycosis - ot/o = __ myc/ = __ osis =

Myringotomy - myring/o = ___ tomy =

Myringitis - myring/o = __ itis = __

Otopyorrhea - ot/o = __ py/o = __ rrhea =

Ossiculoplasty - ossicul/o = ___ plasty =

DEFINE THESE DEFINE THESE PATHOLOGICAL PATHOLOGICAL

CONDITIONSCONDITIONS

Audio / gram – Audio / meter – Audio / metry – Oto / scopy –

EAR PROCEDURESEAR PROCEDURES

Figure 17-24. Pure-tone audiometer.

AUDIOMETERAUDIOMETER

Figure 17-26. Otoscopic examination. The auricle is pulled up and back. The hand holding the otoscope is braced against the face for stabilization.

OTOSCOPIC EXAMOTOSCOPIC EXAM

Chapter 17Chapter 17 (Cont’d)

TheThe

Cor/o and Pupil/o = pupilPupil - the dark center of the eye

Conjunctiv/o – conjunctivaConjunctiva – clear membrane that lines inner surface of eyelids & over whites of eyes.

Corne/o and kerat/o = corneaCornea – a fibrous, transparent tissue that extends over the pupil of the eye and iris. Helps with refraction of light.

STRUCTURES OF THE STRUCTURES OF THE EYEEYE

Pupil

Conjunctiva

Cornea

Scler/o – scleraSclera – white part of the eye. Avascular – no blood vessels.

Choroid – dark brown membrane inside sclera.


ScleraChoroid

Ir/o – irisIris – colored portion of

the eye. • Is also a muscle that

surrounds pupil of the eye.

• If light is bright, the iris gets bigger (contracts) & pupil gets smaller (constricts).

• If light is dim, the iris relaxes & pupil dilates (gets larger).

Mi/o – smaller, less Miosis: constriction of the pupilMydr/o – wider, enlarge Mydriasis: enlargement of pupil


Iris

Ciliary Body

Cycl/o – ciliary bodyCiliary body – a muscle located next to the lens and that two functions:1. Thickens & thins the lens for refraction (bending of light rays)2. Secretes aqueous humor (AH)Aqueous Humor – fluid that maintains shape of anterior portion of eye & provides nourishment to structures in the same area.


Ciliary Body

Phak/o and phac/o – lens of the eyeLens – flat for distant vision and rounded for close vision. Also helps with refraction of light.

Refractive power of lens is ACCOMODATIONACCOMODATION


Lens

Anterior Chamber of Eye:

• Contains aqueous humor

• Secreted by ciliary body

• Maintains shape of anterior eye

• Constantly produced - leaves eye thru canal that carries it to bloodstream


Anterior Chamber

Vitreous Chamber of Eye:

• Contains vitreous humor

• Maintains shape of posterior eye

• Refracts light rays• Is NOT constantly

being produced• Loss of VH may

mean loss of eye


Vitreous Chamber

Retin/o - retinaRetina – thin, nerve layer that contains rods and cones.

• Rods are for reduced lighting and peripheral vision.

• Cones are for color and central vision.


Retina

• When light energy hits rods & cones (in retina) causes chemical changes, that initiate nerve impulse to travel to brain via the optic nerve

• Optic disc is area where optic nerve meets retina (it has no light receptors – so called blind spot)


Optic Nerve

Optic Disc

Macula

Fovea Centralis

• Macula is small area to the side of the optic disc

• Macula contains the Fovea Centralis: location of sharpest vision within eye (composed largely of cones)


Optic Nerve

Optic Disc

Macula

Fovea Centralis

Figure 17-3. The posterior, inner part (fundus) of the eye, showing the retina as seen through an ophthalmoscope.

RETINARETINA

• Optic Nerve Fiber – carry light stimulus through nerve fibers to the brain.

• As fibers enter brain, travel more medially & eventually cross.

• Optic Chiasm – area where optic nerve fibers cross

• Nerve fibers from right 1/2 of each retina form an optic tract & synapse in thalamus.

• Fibers end in the right visual field of the cerebral cortex.

• Same thing happens with the left half of each retina

• Images fuse, giving 3 dimensional image: called Binocular Vision

BINOCULAR VISIONBINOCULAR VISION

Figure 17-5. Pathway of light rays from the cornea of the eye to the cerebral cortex of the brain.

PATHWAY OF LIGHTPATHWAY OF LIGHT

• Thalamus – nerve fibers from right half of each retina form an optic tract and synapse in the thalamus. Fibers will end in the right visual field of the cerebral cortex. Same thing happens with nerve fibers on the left half of each retina.

• Cerebral Cortex – surface of cerebrum where nerve cells lie in sheets. Receive visual stimulus from thalamus from both sides of the eye.

• Visual area of cerebral cortex is in occipital lobe of the brain.

AREAS OF BRAIN INVOLVED IN AREAS OF BRAIN INVOLVED IN VISIONVISION

• Accommodation – normal adjustment of the eye for seeing objects at various distances – eye has more problems with this as ages

• Astigmatism – defective curvature of the cornea or lens of the eye.

• Presby/opia – impaired vision of the cornea or lens of the eye, associated with aging.

• Hyper/opia – farsightedness (can’t see close objects), rays of light focus behind retina

• My/opia – nearsightedness (can’t see far away objects), rays of light focus in front of the retina

VISIONAL DISTURBANCESVISIONAL DISTURBANCES

(A)(A) Astigmatism and its correction.Astigmatism and its correction.(B)(B) Hyperopia and its correction. Hyperopia and its correction. (C)(C) Myopia and its correction. Dashed lines in Myopia and its correction. Dashed lines in

B and C indicate the contour and size of B and C indicate the contour and size of the normal eye. the normal eye.

ERRORS OF ERRORS OF REFRACTIONREFRACTION

• Astigmatism – defective curvature of the cornea or lens of the eye.

• Presby/opia – impaired vision of the cornea or lens of the eye, associated with aging.

• Hyper/opia – farsightedness (can’t see close objects), rays of light focus behind retina

• My/opia – nearsightedness (can’t see far away objects), rays of light focus in front of the retina

Ambly/o = DULL, DIMDULL, DIM Amblyopia = Dipl/o = DOUBLEDOUBLE Diplopia = Nyct/o = NIGHTNIGHT Nyctalopia =Phot/o = LIGHTLIGHT Photophobia = -opsia = VISIONVISION Hemianopsia

= Blephar/o = EYELIDEYELID

Blepharoptosis = Dacry/o = TEAR DUCTSTEAR DUCTSLacrim/o = TEARSTEARS Lacrimal ducts

=

COMBINING FORMSCOMBINING FORMS

Lacrimal (tear) gland and ducts.

LACRIMAL TEAR LACRIMAL TEAR DUCTSDUCTS

OD – RIGHT EYERIGHT EYEOS – LEFT EYELEFT EYEOU – BOTH EYESBOTH EYESVF – VISUAL FIELDVISUAL FIELDAH – AQUEOUS HUMORAQUEOUS HUMORVH – VITREOUS HUMORVITREOUS HUMORIOP – INTRAOCULAR PRESSUREINTRAOCULAR PRESSURE

ABBREVIATIONSABBREVIATIONS

Figure 17-6. (A) Acute bacterial conjunctivitis. Notice the discharge of pus characteristic of this highly contagious infection of the conjunctiva. (B) Anisocoria.

DISORDERS OF THE DISORDERS OF THE EYEEYE


Cataract. The lens appears cloudy.


Figure 17-10. Chalazion.

Figure 17-11. Glaucoma and circulation of aqueous humor. Circulation is impaired in glaucoma, so that aqueous fluid builds up in the anterior chamber.


Figure 17-12. (A) Picture as seen with normal vision. (B) The same picture as it would appear to someone with macular degeneration.


A normal fluorescein angiogram.

PROCEDURESPROCEDURES

Figure 17-14. Ophthalmoscopy. In addition to examining the cornea, lens, and vitreous humor for opacities (cloudiness), the examiner can see the blood vessels at the back of the eye (fundus) and note degenerative changes in the retina.


Figure 17-15. Slit lamp examination measuring intraocular pressure by tonometry.


(A) The Snellen chart assesses visual acuity. (B) Visual fields are examined by comparing the patient's field of vision with that of the examiner's (assuming the examiner's is normal).


Keratoplasty – surgical repair of the cornea (corneal transplant)

Vitrectomy – removal of vitreous humor

SURGICAL SURGICAL TREATMENTSTREATMENTS

Figure 17-17. Clinical appearance of the eye after keratoplasty. (Courtesy of Ophthalmic Photography at the University of Michigan, WK Kellogg Eye Center, Ann Arbor, MI. From Black JM, Hawks JH, Keene AM: Medical-Surgical Nursing: Clinical Management for Positive Outcomes, 6th ed. Philadelphia, WB Saunders, 2001, p. 1822.)

Figure 17-18. Phacoemulsification of a cataractous lens through a small, self-sealing, scleral-tunnel incision. (From Lewis SM, Heitkemper MM, Dirksen SR: Medical-Surgical Nursing: Assessment and Management of Clinical Problems, 5th ed. Mosby, St. Louis, 2000, p. 454.)

Figure 17-19. (A) Detached retina. (B) Scleral buckling procedure to repair retinal detachment. (From Ignatavicius DD, Workman ML: Medical-Surgical Nursing: Critical Thinking for Collaborative Care, 4th ed. Philadelphia, WB Saunders, 2002, p. 1041.)

sense organs: the ye & the ear. the ear combining forms for the ear: ot/o, aur/o, auricul/o ...

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