sensory functions Flashcards
stimulus
(light)
sense organ
(eye)
receptor cells
(rods and cones)
action potential (nerve impulse)
(optic nerve)
central nervous system (decoded)
(visual cortex of brain)
somatic sensations come from
skin, muscles, joints
special senses
vision, hearing, balance, taste, smell
visceral sensations come from
internal organs
pain is an _______ _______ and _________ experience.
unpleasant, perceptual, emotional
pain can be ________ or ________.
localized or diffuse
referred pain
-pain that is felt in a region that other then where that pain originated
-felt when internal organs are damaged or inflamed
-sensory neurons from superficial area and neurons of source pain converge onto same ascending tracts in the spinal cord
-the brain gets confused and associated the pain w the superficial area
the eye
-cornea/sclera
-iris/pupil
-lens
-retina
disorders of the eye
-aging effects: presbyopia
-infections disorders: conjunctivitis
-chronic eye disorders: glaucoma, cataracts, macular degeneration, retinal detachment
presbyopia
-age related eye changes may begin as early as 30 yrs of age
-vision become less acute and less able to distinguish details
-physical changes accnt for most of the other sensation changes
(presbyopia) eye changes include
-less tear production
-structural deteriorations
-corneas become less sensitive
-pupil size decreases and reacts more slowly
-lens becomes yellowed, less flexible, and slightly cloudy
conjunctivitis
-infection or inflammation of the conjunctiva
-caused by viruses (most common), bacteria (e.g., Staphylococcus, Chlamydia, and gonorrhea), allergens (e.g., pollen and dust), chem irritants, and trauma
-bacterial and viral conjunctivitis are highly contagious through direct contact
-can generate edema, pain, blurry vision and photophobia
risk factors of conjunctivitis
wearing contact lenses and using contaminated makeup or ophthalmic meds (eye drops)
many chronic conditions affecting the eyes are progressive and can result in visual deficits
-glaucoma: increased ocular pressure
-cataracts: clouding of the lens
-macular degeneration: deterioration of the retina
glaucoma
-group of eye conditions that lead to damage to the optic nerve
-these increased pressures cause ischemia and degeneration of the optic nerve
-second leading cause of blindness (diabetic retinopathy is number one)
causes of glaucoma
-increased intraocular pressure and decreased blood flow to the optic nerve
-pressures inside the eye increases w changes of aqueous humor
-caused by either outflow of aqueous humor becoming blocked or production of aqueous humor increases to an abnorm level
chronic (open-angle) glaucoma
degeneration and obstruction of trabecular meshwork and canal of Schlemm decreases absorption of aqueous humor
cataracts
-opacity or clouding of the lens
-can occur as a congenital condition or develop later in life
-may affect one or both eyes and do not necessarily affect eyes symmetrically
risk factors for adult-onset cataracts
-fam history
-advancing age
-smoking, ultraviolet (UV) light exposure
-metabolic conditions (e.g., diabetes mellitus)
other manifestations (cataracts)
-cloudy, fuzzy, foggy, or filmy vision
-color intensity loss
-diplopia
-impaired night vision
-halos around lights
-photosensitivity
macula dengeration
-deterioration of the macular area of the retina
-caused by impaired blood supply to the macula that results in ischemia
-the most significant risk factor for this condition is advancing age
risk factors of macula degeneration
-fam history
-smoking, increased UV light exposure
-cardiovascular disease, hypertension, and obesity
manifestations of macula degeneration
-blurry vision
-dark spots in central vision
-loss of central vision
-distortion of straight lines
retinal detachment
-retina separates from deeper supporting structures
-as vitreous humor collects underneath it, the retina peels away from the underlying choroid
-these detached areas may expand over time
-the retina becomes ischemic and stops functioning, causing vision loss
causes of retinal detachment
Causes: spontaneous, severe nearsightedness, trauma, diabetes mellitus, degenerative aging changes
-caused by vitreous humor leaking through a retinal tear and accumulates underneath the retina
-tiny holes where the retina has thinned due to aging or other retinal disorders
manifestations of retinal detachment
typically painless, flashes of light in the peripheral visual field, blurred vision, floaters, and darkening vision (like a curtain drawing)
external ear
-canal, tympanic membrane
middle ear
ossicles, auditory tube
inner ear
cochlea, semicircular canals
congenital disorders (ear)
anotia, microtia, atresia
aging effects (ear)
presbycusis
infectious disorders (ear)
otitis media, otitis externa
chronic ear disorders
otosclerosis, tinnitus, meniere’s disease, vertigo
congenital disorders of the ear
-anotia: absence of the auricle
-microtia: underdeveloped, small auricle
-atresia: lack of an external ear canal
-often associated w other congenital conditions affecting the head
-may be unilateral or bilateral
-may still have norm middle and inner ear function
presbycusis
-age related hearing loss
-all the ear structures thicken w aging, can affect balance and hearing
-hearing may decline slightly, especially w high freq sounds
-hearing loss accelerates in ppl who were exposed to excessive noise or smoking when they were younger
otitis media
-infection or inflammation of the middle ear
-common condition in young children bc their Eustachian tubes are narrower and shorter than those of adults and older children and an immature immune system
-additional cause: fluid accumulation in the middle ear due to adenoid enlargement, usually due to inflammation
-typically begins as a viral upper respiratory infection
complications of otitis media
effusions, rupture of the tympanic membrane, scar tissue, conductive hearing loss, mastoiditis, cholesteatoma, meningitis
manifestations of otitis media
-ear pain w mild hearing deficits
-crying or irritability, rubbing/pulling at the ear
-red and bulging tympanic membrane, indications of infection, purulent or clear exudate from the external ear canal (if the tympanic membrane ruptures)
treatments of otitis media
oral antibiotics
pressure equalizing tubes
otitis externa
-infection or inflammation of external ear canal or auricle
-usually bacterial in origin (often Pseudomonas aeruginosa) but may also be fungal
-generally arises from moisture in the ear that creates an environment ofr bacterial or fungal growth or intro of the organisms from external sources
risk factors of otitis externa
swimming in contaminated water, scratching the outside or inside of the ear, irritants, and insertion of foreign objects
complications of otitis externa
hearing loss, cellulitis, necrosis, osteomyelitis, and meningitis
manifestations of otitis externa
ear pain that worsens w auricle movement, purulent exudate, itching, a sensation of fullness in the ear, and hearing deficits
otosclerosis
-Abnormal bone grows in the middle ear, preventing the ossicles rom vibrating in response to sound waves
-Base of stapes gets fixed in the oval window
-Conductive hearing loss progressively worsens
otosclerosis manifestations
-Conductive hearing loss progressively worsens
-Tinnitus
treatment of otosclerosis
-Hearing aids to treat the hearing loss
-Surgery to remove the stapes and replace it with a prosthesis
-Laser surgery to create an opening in the stapes
tinnitus
-Hearing abnormal noises in the ear
-May be described as a ringing, buzzing, humming, whistling, roaring, or blowing
tinnitus may be associate with
-presbycusis,
-exposure to excessive noise,
-cerumen impaction,
-otosclerosis,
-Meniere disease, head injury, acoustic neuroma,
-atherosclerosis, hypertension, arteriovenous malformation
-ototoxic medications (e.g., many antibiotics, aspirin, chemotherapies, and diuretics)
vertigo
Illusion of motion
Room spinning
Moving walkway
Not the same as dizziness
Additional manifestations: nausea and vomiting
vertigo various types
-BPVV
-Vestibular Migraines
