Eyes and ears - Vet terminology of the eyes and ears PDF

Preview

Summary

Vet terminology of the eyes and ears...

Description

Terms ● Adnex: Accessory structures ● Stroma: Supporting tissue of structure ● Extrins/o: outside wall ● Blephar/o: eyelid ● Canth/o: corner ● lacrim/o and dacry/o: teardrop, tear duct, or lacrimal duct. ● Punctum: Point or small spot ● Tapeum: medical term for layered cells ● Phac: Lens of eye ● Iridoconeal: Pertaining to the iris and cornea ● Uvea: Describes the iris, ciliary body, and choroid. ● Libus: For the corneoscleral junction ● Lute/o: Yellow ● Macul/o: SPot ● Fove/o: Pit ● Gon/i: Angle or seed ● Ambly/o: dim ● Anis/o: unequal

Acessories ● Adexna: Acessory strucutres ○ Adnexa of the eye include the orbit, eye muscles, eyelids, eyelashes, conjunctiva, and lacrimal apparatus ● Orbit: Bony cavity of the skill that contains the eyeball. ○ Periorbita: means eye socket ● Stroma: Supporting tissue of strucutre ● The angle where the upper and lower eyelids meet is called the canthus. ● Tarsal plate: Platlike framework within the upper and lower eyelids that provides stiffness and shape. ● Meibomian glands (tarsal glands): Are the sebaceous glands on the margins of each eyelids ● Eyelashes: The edge of each eyelid has hairlike strucutres callled cilia ● Conjuctiva: Mucous membrane that lines the underside of each eyelid. Forms a protective covering of the exposed surface of the eyeball when the eyelids are closed. ○ The nictitating memrane is the conjunctival fold attached at the medial canthus that moves across the cornea when the eyelids close; the third eyelid. ● Lacrimal apparatus: Structures that produce, store, and remove tears. ○ Lacrimal canaliculi: ducts at the medial canthus that collect tears and drain them into the lacrimal sac ○ Lacrimal sac or daryocyst: collects tears at the upper portion of the tear duct

○ ○ ○

Nasolacrimal duct: drains tears inot the nose Dorsal punctum: small spot near the upper medial canthus where the nasolacrimal duct begins. Ventral punctum: Small spot near the lower medial canthus where the nasolacrimal duct begins

○

●

● ●

Eyemuscle: Seven major muscles attached to each eye that make a rand of movement possible (2 oblique muscles, 4 rectus muscles, and the retractor bulbi) ○ The muscles of both eye work together in coordinated movement to make biocular vision possible Extrinsic muscles are 6 muscles that attach the outside of the eyeball to the bones of the orbit Eyelids (Palebra): each eye has an upper and lower eyelid to protect the eye from injury, foreign material, and excessive light.

Eyeball ● Multi-layered wall: Sclera, choroid, and retina. ● Sclera: fiberous layer of the eye that maintains the shape of the eye ○ White of eye ○ The thin membrane covering the sclera is the episclera ○ Anterior portion o the sclera is transparent and is called cornea. ■ Cornea provides most of the focusing power of eye ■ Descements membrane is the innermost or deepest layer of the cornea Choroid ● Opaque middle layer of the eyeball that contains blood vessles and supplies blood for the entire eye. ● The tapetum lucidum is the brightly colored iridescent reflecting tissue layer of the choroid of most species ● Associated with the choroid are the iris, pupil, lens, and ciliary muscles. ● Iris is the pigmented musclular diaphram of the choroid that surrounds the pupil. ○ Iris is composed of muscle fiber rings that contract or relax to change the size of the pupil. ○ Miosis: Constriction ○ Mydrasis: Dialation ● Porpora nigra: Black pigmentation of the edge of the iriss in equine and ruminants ● Lens: clear, flexible, avascular, curved capsule located posterior to (behind) the iris and pupil. ○ Altered by ciliary, adjusting the shape of the lens to improve near or far vision is known as accommodation. ● Ciliary body: Thickened extension of the choroid that assists in accommodation or adjustment of the lens

Retina ● Nervous tissue layer of the eye that receives images and line the posterior chamber of the eye. ● Contians rods and coens the convert visual images to nerve impulses that travel from the eye to the brain via the optic nerve ○ Rods: react to light ○ Cones: React to color and fine detail ● Optic disk is the region of the eye where nerve endings of the retina gather to form the optic nerve. ○ Also called the blind spot, does not contain any rod or cones ● The macula lutea: Centrally depressed, clearly defined yellow area the center of the retina ● The fovea centralis: Contains the greatest concentration of cones in the retina (no rods) and the area of sharpest vision. ● Fundus: Part of retina opposite the lens the includes the retina, optic disc, macula lutea, and fovea centralis

Eye chambers

Vision ● Occurs when light rays eneter the eye through the cornea, pass through the lens, and travel to the retina.The image is fouced on the retina and is then trasmitted to the optic nerve. Stimulations are transmitted fromt he optic nerve, to the optic chiasm, to the midbrain, and to the visual cortex of the occipital lobe or the cerebrum. ○ Accommodation: The process of eye adjustments for seeing objects at various distances. These adjustments are scomplished through changes in lens shapes. ○ Refraction (focusing): The process of the lens bending the light rays to help them focus on the retina. ○ Convergence: Stimultaneous inward movement of both eyes . COnvergece usually occurs in an effort to maintain single binocular vision as an object approaches ○ Acuity: Sharpness or acuteness, usually used in reference to vision Test ● ● ● ●

Conjunctival scrape: Diagnostic test using an instrument to peel cells from the conjuctiva so that they can be viewed microscopically Electroteniography (ERG): Procedure of recording the electrical acivity of the retina. ○ Electrotetinogram: record of electrical activity of the retina Fluorescein dye stain: Diagnostic test to detect corneal injury by placing dye on the surfface of the cornea Goniometry: Measure the drainage angle of the eye

● ●

●

● ● ● ●

Menace response: Detect vision in which movement is made toward the animal to test whether it will see movement and try to close its eyelids Opthalmoscope: Instrument used for opthalmoscopy ○ Opthalmoscopy (Funduscopy): procedure used to examine the interior eye structures; may be direct or indirect

Palpebral reflex: Dianostic test in which the eye should blink in response to touch to the medial canthus of the eye. The test is used to make neurologic assessment of cranial nerves V and VII and to asses depth of anesthesia Pupillary light reflex (PLR): Response of pupil to light. Schrimer tear test: Diagnotic test using a graded paper strip to measure tear production Slit lamp examination: Visual testing of the cornea, lens, fluids, and membranes of the interior of the eye using a narrow beam of light Tonometry: Procedure using an instrument to meaure intraocular pressure indirectly. ○ Intracular pressure (IOP) resistance of the eyeball to indentation by an applied force ○ Schiotz tonometer: Applanation tonometer

○

○ Pathology ● Amblyopia: Dimess of loss of sight without detectable eye disease ● Anisocoria: Donsition of unequal pupil size ● Anophthalmos: Without development of one of both eyes ● Aphakia: Adsence of the lens ● Blepharitis: Inflammation of the eyelid ● Blepharoptosis: Drooping of the upepr eyelid

● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●

● ● ● ● ● ● ● ● ● ● ●

Blepharospasm: Rapid, involuntary contractions of the eyelid Buphthalmos: Abnormal enlargement of the eye Cataract: Cloudiness or opacity of the lens. Chalazion: Localized swelling of the eyelid resulting from the obstruction of a sebaceous gland of the eyelid Conjuctivitis: Inflammation of the conjuctiva Corneal Ulceration: Surface depression of the cornea Cyclpia: Congenital anomalychacterized by a single orbit Dacryoadenitis: Inflammation by the lacrimal gland Dacryocystitis: Inflammation of the lacrimal sac and abnormal tear drainage. Diplpia: 2x vision Distichiasis: Abnormal condition of the 2x row of eyelashes that usually result in conjunctival injury Ectropion: Eversion, or turning outward of the eyelid Entropion: Inversion or turning inward of the eyelid Epiphora: Excessive tear production Episcleritis: Inflammation of the tissue of the cornea Exophthalmos: Abnormal protrusion of the eyeball; sometimes referred to as exophthalmosis Floaters: Particles suspended int he viterous fluid that cast shadows on the retina Glaucoma: Group of disorders resulting from elevated intraocular pressure Hordelum (stye): Infeection of one or more glands of the eye lid Hypertropia: Deviation of one eye upward Hypopyon: Pus in anterior chamber of the eye Hypotropia: Deviation of one eye downward Ititis: Inflammation of the iris Keratitis: Inflammation fo the cornea Keratocunjunctivitis: Inflammation of the cornea and conjunctiva Keratoconjuctivitis sicca (dry eye) (KCS): Inflammation of the cornea and conjunctica due to a tear deficiency and can lead to persistent, mucopurulent discharge and corneal ulceration and scarring. Macular degeneration: Condition of central vision loss Microphthalmia (microphalmos): Abnormally small eyes Monochromatism (color blindness): Lack of ability to distinguish colors Nictitating gland prolapse (Cherry eye): Hypertrophy and protrusion of the conjunctival fold of the medial canthus. Nuclear sclerosis: Drying out the lens with age Nyctalopia (night blindness): Condition of inability or difficulty seeing at night Nystagmus: Involuntary, constant, rhythmic movement of the eye Ophthalmoplegia: Paralysis of eye muscles Panophthalmitis: Inflammation of the eye structures Papilledema: Swelling of the optic disk Photophobia: Fear or intolerance of light

● ● ● ● ● ●

● ●

Proptosis: Displacement of the eye from the orbit Retinal detachment: Separation of the nervous layer of the eye from the choroid Retinopathy: Any disorder of the retina Scleral injection: Dialation of blood vessles into the sclera Scelitis: Inflammation of the sclera Strabismus: Disorder in which the eyes are not directed in a parallel manner; deviation of one or both eyes ○ Convergent strabismus (estropia): Crossed eyes ○ Divergent strabsimus (exotropia): Away from each other Synechia: Adhesion that binds the iris to an adjacent strucutre; plural is synechia Uveitis: Inflammation of the uvea

Procedures ● Blepharectomy: Surgical removal of all or part of the eyelid ● Blepharoplsty: Surgical repair of the eyelid ● Blepharorrhaphy: Suruting together of the eyelids also called; also called tarsorrhaphy ● Blepharotomy: incision of the eyelid; also called tarsoectomy ● Canthectomy: Surgical removal of the corner of the eyelid ● Canthoplasty: Surgical repair of the palpebral fissure ● Canthotomy: Incision into the corner of the eyelid ● Conjuctivoplasty: surgical repair of the conjunctiva ● Dacryocysotomy: Incision into the lacrimal sac ● Enucleation: Removal of the eyeball ● Extracapsular extraction: Removal of a cataract that leavs the posterior lens capsule intact ● Goniotomy: Incision into the naterior chamber angle for treatment of glaucoma ● Intracapsular extraction: Cataract removal that include the surrounding capsule ● Iridectomy: Surgical removal of a portion of the iris ● Surgical removal of part of the cornea ● Keratectomy: Surgical removal par of the cornea ● Keratocentesis: Puncture of the cornea to allow aspiration of aqueous humor ● Keratoplasty: Surgical repair of th cornea (may include corneal transplant) ● Keratotomy: Incision into the cornea ● Lacromotomy: Incision into the lacrimal gland or duct. ● Lensectomy: Surgical removal of a lens (usually performed on cataracts) ● Tarsectomy: Surgical removal of all or part of the tarsal plate of the third eyelid ● Tarsorrhaphy: Suturing together of the eyelids.

Terminology ● Pinn/i, auri, and aur/o: external ear ● Tympan/o and myring/o: eardrum

Outer ear ● Auricle ( Pinna): External portion of the ear that catches sound waves and transmites them to the external auditory canal. ● External auditory (meatus) canal: transmits sound from the pinna to the tympanic membrane sound from the pinna for the tympanic emmebrane ● Cochlear duct: Membrane tube in the bony cochlea that is filled with endolymph. Endolymph vibrates when sound waves strike ● Organ Corti:Spiral organ of hearing located in the cochlea that receives and relays vibrations. Specialized cells in the organ of the corti generate nerve impluses when they are bent by the movement of endolymph. Nerve impulses are relayed to the auditory nerve fibers that transmits them to the cerebral cortex.

Mechanism of hearing ● SOund waves enter he ear through the pinna, travel through the external auditory canal, and strike the tympanic membrane. This is called air conduction. ● As the tympanic membrane vibratese, it moves the ossicles. The ossicles conduct the sound waves through the middle ear. This is called bone conduction. ● Sound vibrations reach the inner ear via the round window. The structures of the inner ear respond to sound waves that displace fluid in the inner ear. Stimulation of hair cells in the organ of Corti initiates a nerve impulse that is transmitted to the vestibulocohlear nerve. This nerve impulse is then relayed to the brain. This is called sensorineural conduction. Mechanism of equilibrium ● In addition to the strucutres lister previously, the ear also have strucutres that maintain equilibrium. The sense of equilibirum is a combination of static equilibrium (maintaing the position of the head relative to gravity) and dynamic equilibrium (maining balance in response to rotational or angular movement)

● ● ● ●

● ●

● ●

Static equilibrium is controlled by organs in the vestibule of the inner ear. The membraneous labyrinth inside the vestibule has a saccule and utricle which are small, hairlike sacs. The saccule and utricle contain a macula an organ consisting of hair cells covered by a gelatinous mass containing otoliths which are small stones When the head is upright position, the hair are straights. When the head tilts or bends, the otoliths and gelatinous mass move in response to gavity. ○ As the gelatinous mass moves, it bends some of the hairs on the receptor cells, which in turn initiates impulse that stimulates the vestibular branch of cranial VIII. Dynamic equilibrium is controlled by the semicircular canals. 3 semicircular canals in the inner ear lie in planes at right angles to each other. At the base of each canal is a swelling called the ampulla, which contains sensory organs called cristae. ○ Each cristae contains sensory hair cells and gelatinous mass. When the head turn rapidly, the semicircular canals move with the head, but the endolymph within the membrane of the semicicular canals remains stationary. The fluid in the semicicular canals pushes agianst the gelatinous mass, which bends some of the hairs on the hair cells.

Pathology ● Otoscopy: Procedure used to examine the ear for parasites, irritation to the ear lining, discharge, and the integrity of the tympanic membrane. ● Aural hematoma: Collection or mass of blood on the outer ear. ● Deafness: Complete or partial hearing loss ● Myringitis: Inflammation of the eardrum ● Otalgia: Ear pain ● Otitis: Inflammation of the ear; usually has a second term that describes the location ○ Otitis extrena: Inflammation of the outer ear

● ● ● ● ●

○ Otitis media: Inflammation of the middle ear ○ Otitis interna: Inflammation of the inner ear Otomycosis: Fungal infection of ear Otopathy: Disease of the ear Otopyorrhea: Pus dicharge from the ear Panotitis: Inflammation of all ear part Vertigo: Senese of dizziness

Procedures ● Ablation: Removal of a part ● Myringectomy: Surgical removal of all or part of the eardrum; also called tympanectomy ● Otoplasty:Surgical repair of the ear Abbreviations

● ● ● ● ● ● ● ● ●

AD: Right ear AS: Left rights ERG: Electroretinogram IOP: Intaocular pressure KCS: Keratoconjunctivitis sicca OD: Right eye OS: left eye OU: both eyes PLR: Pupillary light response...