Chapter 14: Special Sense Organs Flashcards
Receptors
sensory nerve endings that respond to stimulus
Sense organs
eyes, nose, ears, mouth, skin
Pupil
light enters here and the muscles of the iris constrict and dilate to regulate light exposure
Iris
colored part of the eye
Sclera
tough outer layer, white eyeball
Accessory organs of the eye
muscle, fascia, eyebrows, eyelid, conjunctiva, lacrimal glands
Conjunctiva
lines inner portion of eyelid and protects part of the eye that is exposed
Lacrimal glands
produce and store tears
Lacrimal ducts
tears pass through these small openings
Nasolacrimal sac
connection between lacrimal and nasolacrimal
Pathway of a tear
produced in lacrimal glands wash over eyeball pass into lacrimal ducts drain into nasolacrimal sac pass into nasolacrimal duct for drainage
Cornea
transparent film at front of eyeball that bends/refracts light to shift focus to proper receptor cell in eye
Choroid
dark brown membrane inside sclera that is continuous with iris and ciliary body
Ciliary body
surround outside of lens to allow for change in chape and thickness of lens
secretes acqueous humor
Refraction
flattening of lens (distant vision)
rounding of lens (close)
Accommodation
refractory adjustment for close vision
Anterior chamber
area that contains acqueous humor
Vitreous chamber
filled with soft jelly material called vitreous humor
Escape of what fluid could cause considerable damage to eye
vitreous humor
Retina
nervous tissue membrane of the eye
continuous with optic nerve
enables vision
Optic disc
region where optic nerve meets retina
Which area of the eye does not contain light receptors?
optic disc
Rods
responsible for peripheral vision
night vision
motion detection
Cones
three types function in bright light
color and central vision
Most cases of color blindness affect which color receptor cones?
red and green
Daltonism
weakness in perceiving colors distinctly
Achromatic vision
total color blindness
Snellen chart
tests clarness or sharpness of vision
normal vision is 20/20
top number is feet patient is standing from chart, bottom number is number of feet a normal person would be from the chart
Opthalmometer
instrument used to measure eye, specifically the cornea
Myopia
nearsightedness
parallel rays entering eye are focused in front of retina
Hyperopia
farsightedness
inability of eye to focus on nearby objects
rays of light brought to focus behind retina
Astigmatism
distortion of curvature of lens or cornea
results in uneven focusing
Tonometry
measurement of intraocular pressure, usually after numbing eye
Mydriatic
agent that dilates pupils
Presbyopia
hyperopia and impairment of vision due to age
Accommodation reflex
ability of eye to adjust to variations in distance
Fluorescein angiography
uses fluorescein to examine movement of blood through eye
Amblyopia
reduced vision in one eye
not correctable by glasses
corrected by eye patch
aka strabismus
Blepharitis
inflammation of eyelid
Cataract
progressive condition of lens characterized by loss of transparency
Achromatopsia
profound inability to see color
Conjunctivitis
inflammation of the conjunctiva
Glaucoma
abnormal increased pressure in eye, which can cause damage to retina and optic nerve
Hordelum
sty
Macular degeneration
progressive deterioration of retina associated with new vessel fromation that can progress to blindness
Nyctalopia
poor vision at night or in dim light
Photophobia
excessive sensitivity to light
Ptosis
drooping of upper eyelid
Retinal detachment
separation of retina from choroid, usually from tear or hole in retina
Retinopathy
disease of the retina
Iridectomy
surgical removal of part of iris to allow for proper drainage in glaucoma patients
Cerumen
ear wax
How is the ear divided
external, middle, internal
External ear
visible part of ear
ends at tympanic membrane
Middle ear
air filled cavity containing ossicles
Internal ear
contains cochlea and semicircular canals
What are the ossicles in the middle ear
malleus
incus
stapes
What contains receptors for sense of balance?
semicircular canals
Semicircular canals
fluid-filled vanals that open into cochlea
Cochlea
spiral tunnel resembling snail shell
Eustachian tube
leads from middle ear to pharnx
can prevent damage to tympanic membrane by equalizing pressure
Otoscopic examination
examination of ear using otoscope
Audiologist
detects and evaluates hearing loss
Audiometer
electronic device for measuring hearing
Audiogram
record produced by audiometer
Deafness
inability to hear
Tuning fork test
Weber’s test
tests auditory nerve and ability of ear structures to conduct sound waves to inner ear
Otitis
inflammation of ear
Otorrhea
may contain blood, pus, or spinal fluid
Otalgia
pain in the ear
Otitis media
inflammation of middle ear
Myringitis
inflammation of tympanic membrane
Mastoiditis
infection of one of the mastoid bones of the skull, usually extension of middle ear infection
Otitis externa
external ear infection often caused by fungus
Otomycosis
otitis externa
Otitis interna
inner ear infection
Otosclerosis
hardening of the ear
Tinnitus
noise in the ear
either from accummulation of cerumen or something more complex
Vertigo
dizziness
Cochlear implant
used in complete hearing loss
electrically stimulates cochlea
Otoplasty
srugical repair of the ear
Tympanostomy
surgical creation of opening in tympanic membrane to allow for drainage
Ceruminolytics
medications used to soften and break down ear wax
Nociceptors
pain receptors
Olfaction
sense of smell
Olfactory
pertaining to sense of smell
Anosmia
loss or impairment of sense of smell