The Ear. Functions of the ear Hearing – detects vibrations in air and converts these vibrations to...

The Ear

Functions of the ear

Hearing – detects vibrations in air and converts these vibrations to nerve impulses

Impulses are sent to the brain and interpreted as sounds

Balance – vestibule in inner ear is responsible for balance

It detects changes in body position and sends this info to brain via nerve impulses

Anatomy & Physiology of Ear

There are three divisions of the ear

1. External ear – the pinna ( or auricle) gathers and passes sound vibrations through the auditory canal

2. Middle ear – the tympanum (or eardrum) transmits sound vibrations to in inner ear

3. Inner ear – also known as labrinyth receives sound vibrations and transmits messages to brain via nerve impulses

Middle Ear Ossicles

There are three bones called ossicles

Malleus – (hammer) Incus Stapes – (stirrup)

The ossicles transmit vibrations from the

tympanic membrane to the inner ear

Inner Ear - Cochlea

Cochlea is known as the organ of hearing Cochlea is a snail shaped structure filled with

fluid and hair cells These cells respond to vibrations in the fluid

and produces nerve impulses The impulses are sent to the auditory centre

of the brain

Word componentsWord root Combining

formMeaning

Acoust acoust/o hear/sound

Audi audi/o hear/hearing

Aur aur/o,aural ear

Auricul auricul/o ear / pinna

Cerumin cerumin/o cerumen / ear wax /

Cochle cochle/o cochlea,snail (receptor for hearing in inner ear

Incud incud/o,incudal incus bone or anvil

Word ComponentsWord root

Combining form

Meaning

Labrinyth labrinyth/o maze, twisted spiral shape

Malle Malle/o Malleus bone or hammer

Mast Mastoid/o breast, nipple shaped

Myring myring/o membrane

Ot ot/o ear

Staped stapedi/o

staped/o

stapes bone or stirrup

Salping salping/o eustachian or trumpet tube

Tympan tympan/o drum pg 1

Ear inflammation / infections

Otitis externa

Otitis media

Otitis interna

Otitis media - more common due to the middle ear’s connection to Eustachian tube

pg2

Procedures for ear

Examination – aural speculum allows better viewing of tympanic membrane with auriscope

Auriscope – instrument used to examine ear canal and tympanic membrane

Aural syringe – instrument used to lavage (wash out) ear that is blocked with cerumen

pg2

Glue ear Is the build up of fluid behind tympanic

membrane Surgical puncture…..allows drainage from

middle ear Fluid drains into Eustachian tube to

nasopharynx Grommets can be fixed to tympanic

membrane to assist drainage pg3

AbbreviationsAC air conduction

AD auris dextra(right ear)

AS auris sinistra (left ear)

Aud audiology

BC bone conduction

ENT ear, nose throat

ETF eustachian tube function

OE otitis externa

OM otitis media

Oto otology

Ear Conditions / Terms

Term Meaning

conductive deafness

hearing impairment resulting from obstruction of sound waves

glue ear accumulation of fluid in middle ear

Menieres Disease

disorder of inner ear characterized by vertigo, deafness and tinnitus

otalgia pain in ear (earache)

otorrhagia bleeding from the ear

tinnitus continuous ringing or buzzing noise in ear

Vertigo dizziness, sensation the the person or surroundings are spinning

Ear procedures

Procedure Meaning

audiogram recording tracing of hearing

myringoplasty surgical repair of perforated ear drum

myringotomy surgical incision into the eardrum

ossiculoplasty surgical repair of the ear bones

otoplasty plastic surgery of the ear

stapedectomy removal of the stapes

tympanoplasty surgical repair of the tympanic membrane when disease such as infection involved

THE EYE

Organ of sight

Function of the eye

Identification of shapes and colours

Physiology of vision

Light enters eye through the pupil The lens focuses light rays on the retina

which is the nerve tissue of the eye Visual receptor neurons (known as rods and

cones) in retina respond to these light rays Nerve fibres join in the optic disc Optic disc carries nerve impulses to the brain

Professional branches of vision

Optometry Is the measuring of visual acuity and fitting of

glasses to correct visual defects

Ophthamology Is the study of the eye and vision

Opticianry Is the practice of filling prescriptions for glasses,

contact lenses and ophthalmic lenses pg1

Word Components

Word root Combining form Meaning

Ophthalm Ophthalm/o eye

Ocul ocul/o; -ocular eye

Opt opt/o sight

Word Components

Word root Combining form

Meaning

Blephar blephar/o eyelid

Sclera scler/o hard (white of the eye)

kerat kerat/o cornea / horny / epidermis

Ir ir/o, irid/o iris (coloured part of eye that bends regulating amount of light entering eye

Cycl cycl/o ciliary body

The eyeball

2 large cavities separated by the lens of the eye

Anterior Cavity– divided into 2 parts by iris

Is filled with watery fluid called aqueous humor

Posterior Cavity– lies between the lens and retina of the eye

Contains a jelly like substance called the vitreous humor

Word components

Root/prefix/suffix

Combining form

Meaning

goni goni/o peripheral angle of the eye

pupil pupill/o pupil

cor cor/o pupil

choroid choroid/o middle pigmented vascular coat of the posterior section of eyeball

Retin retin/o light sensitive area of eye

Papill papill/o nipple shaped

Word ComponetsRoot/prefix/suffix

Combining form

Meaning

Phak phac/o,phak/o lens of the eye

Scot scot/o, scotoma blindspots of vision

Lacrim (Latin) lacrim/o tear

Dacry (Greek) dacry/o tear or lacriminal apparatus

cili cili/o eyelash

Corne corne/o cornea (transparent circular anterior part of eyeball

cyst cyst/o bladder or sac

-opia condition of vision

Vitre Vitre/o glass pg 3

Layers of the eye

Sclera – outer layer of the eyeball Is the white of the eye covers entire eyeball

except cornea Cornea – transparent protective covering of

the iris Iris – coloured part of the eye and regulates

amount of light entering eye through the pupil Pupil – black hole in the middle of eye pg4

Layers of the eye

Choroid – thin brown layer that lines internal surface of sclera

- is between the retinal and sclera layers Retina – inner layer of the eye

forms images to see colour shades and movements

Lacrimal apparatus provides lubrication with it’s

fluid and drains into the lacrimal sac and enters the nose pg4

Conditions and Terms

Astigmatism vision defect where vision is distorted

Cataract opacity of the lens of the eye

Choroiditis inflammation of layer between retina and sclera

Conjunctivitis inflammation of the conjunctiva

Emmetropia light falls on retina in correct position i.e normal vision

Entropion inward turning of eyelid

Glaucoma abnormal pressure of the fluid in the eye

Hypermetropia long sightedness;light rays are focused beyond retina

Conditions and Terms

Keratitis inflammation of the cornea

Myopia shortsightedness

Nystagmus involuntary movement of eye

Orthoptics pertaining to study and treatment of muscle imbalances of eye i.e.squints

Strabismus squint

Stye inflammation of the gland at base of eyelash

Trichiasis eyelashes rubbing against cornea

Xeropthalmia dry eyes