Special Senses eyes and ears Flashcards
Houses and safeguards the eyeball, made up of seven cranial bones that make up the walls.
Orbit
roof of the orbit is
Frontal bone
blood supply of eyeball
Ophthalmic artery
(branch of the internal carotid artery)
85% of the fibrous layer, visible as the white part of the eye, provides attachment to the extraocular muscles
Sclera
continuous with the sclera, positioned centrally at the front of the eye, CONVER, refracts incoming light to help focus light on the lens into the retina
Cornea
cornea is innervated by
V1 (sensory)
Cornea is curved, nearsightedness, eyeball is too long, near objects are seen clearly, far objects are blurred. Corrected with concave lens.
MYOPIA
Cornea is too flat or eyeball is too short, farsightedness, far objects are seen clearly, near objects are blurred, corrected with convex lens.
Hyperopia
Irregular curvature of the cornea or lens, blurred or distorted vision at all distances, corrected by cylindrical lens
Astigmatism
layer of the cornea
External stratified squamous epithelium
Provides nourishment to the outer layers of the retina
Choroid
obstruction of the drainage of the aqueous humor, increasing the pressure in the anterior chamber. May cause the vitreous body to press against the retina affecting vision.
GLAUCOMA
DOC for glaucoma
Pilocarpine
- 2% ophthalmic solution
a transparent, biconvex structure held in place by a circular system zonular fibers and ciliary body. Avascular and highly elastic, controls focus for near or distant vision by a change in its shape
LENS
Loss of ability to undergo accommodation, occurs in the 4th decade of life when the lenses lose elasticity “related to aging”
Presbyopia
lens becomes opaque due to the denaturation of crystallins impairing vision, caused by excessive exposure to UV light, trauma or secondary effects from diabetes mellitus and hypertension
CATARACT
Interruption of the sympathetic nerve supply to the eye, characterized by classic triad: Miosis, Partial ptosis (drooping of the eyelid) Hemifacial Anhydrosis
Horner’s Syndrome
aperture in the center of the iris, allows fluid to pass from the anterior to posterior chamber.
PUPIL
Light detecting component of the eye
RETINA
Contains the photopigment rhodopsin, for nondiscriminative vision, used for seeing in the dark and detecting motion
Rod
contains the photopigment OPSIN, for acute vision (high resolution) used for detecting colors.
Cone
Large glial cells unique to the retina. Critical for retinal function, provides tropic and metabolic support for adjacent neurons
MULLER CELLS
Inherited disorder that results in the defect in the development of one or more of the cone cells
Color Blindness
most common color blindness
Red-green color blindness
inhibitory, causes hyperpolarization of bipolar neurons preventing sending of signals to the ganglion cells.
Glutamate
Thin, transparent mucosa that covers the exposed, anterior portion of the sclera, secretes mucous added to the tear film coating the epithelium and cornea
Conjunctiva
also known as pink eye. inflammation of the conjunctiva due to bacterial or viral infection, also due to alleries.
Conjunctivitis
Viral infection of conjunctivitis is
Adenovirus
Pliable structures containing skin, muscle and conjunctiva and supporting tissue that protect the eye
Eyelids
Lacrimal gland is found on
Superolateral portion of the eye
sigmoid shaped tube extends from the deep part of the concha to the tympanic membrane
External Auditory Meatus “Auditory Canal”
transfers sound vibrations from air to auditory ossicles, external surface is covered by epidermis, internal surface consists of a mucous membrane
TYMPANIC MEMBRAME “EARDRUM”
-crossed by chorda tympani
air-filled cavity on the temporal boned lined with mucous membrane, amplifies the sound waves to the inner ear through the superior oval flow.
Tympanic cavity “Middle Ear”
- contains the ossicles: Malleus, incus and stapes.
Auditory canal is part of external part of ear “external auditory meatus” , Auditory tube/Eustachian canal is part of/connection of middle ear to the nasopharynx area.
Auditory canal is part of external part of ear “external auditory meatus” , Auditory tube/Eustachian tube is part of/connection of middle ear to the nasopharynx area.
equalizes the pressure of the middle ear to the external auditory meatus, normally it is collapsed maintaining slightly negative middle ear pressure.
Eustachian tube
- opens during swallowing and during maintaining pressure.
- route of spread of respiratory infection.
- connects the middle ear to the nasopharynx
pulls the malleus and tympanic membrane medially, inserts to the handle of malleus, origin auditory tube.
Tensor Tympani
Tensor tympani nerve
CN V3
Stapedius is innervated by what CN
Facial Nerve
Transmit sound from the middle ear, connective tissue membrane that separates the middle ear from the vestibule.
OVAL WINDOW
Allows movement of fluid within the cochlea for sound detection, connective tissue membrane that separates the middle ear from the cochlea
ROUND window
inflammation of the middle ear
Otitis media
series of cavities composed of the cochlea, vestibule and semicircular canals
Bony labyrinth
- lined with periosteum and contains perilymph
lies within the bony labyrinth, contains ducts and sacs: cochlear duct, and the vestibular apparatus.
Membranous labyrinth
- filled with endolymph rich in potassium ions
connected to the cochlear portion of the CN VIII, houses the cochlear duct, which separates the cochlea into two fluid-filled chambers
Cochlea
senses balance and body position, relay information to the central nervous system regarding head position as well as acceleration of the head via the vestibulae portion of CN VIII
Semicircular Ducts
central part of the bony labyrinth
Vestibule
receives the semi-circular ducts, detect movement or acceleration of the head in the horizontal plane.
Utricle
Receives the cochlear duct, detect movement or acceleration of the head in the vertical plane.
Saccule
hearing range
20-20,000 hz
