Ch. 14 Sensory Function Flashcards
what are the five types of receptors that the body contains for the general and special senses, and what activates each?
mechanoreceptors - mechanical stimuli such as touch or pressure
chemoreceptors - chemicals in the blood, food, or air
thermoreceptors - heat or cold
photoreceptors - light
nociceptors - painful stimuli
what are the general senses? what are the special senses?
general senses - pain, light tough, pressure, temp, proprioception
special senses - taste, smell, sight, hearing, and balance
what do exposed nerve endings detect and where are they located?
detect pain, temp, and light touch and are located in the skin, bones, and internal organs
where are encapsulated nerve endings located and what do they provide?
located throughout the body for a variety of senses
what is the most common reason that people seek medical attention? it can also be used in diagnosis.
pain
what can the pain threshold be influenced by?
affective (emotional), behavior, cognitive (beliefs and attitudes), sensory (perceptual), and physiologic factors
what can unrelieved pain do?
delay healing, stimulate the stress response and result in pain tolerance
results from noxious stimuli to the joints, muscles and tendons. cutting, crushing, extreme temp, pinching, and irritating chemicals may be stimuli that cause it. generally easy to pinpoint
somatic pain
results from noxious stimuli to the internal organs. stimulus like expansion and hypoxia. pain is usually vague and diffuse.
visceral pain
chronically progressing pain that is unrelenting and severely debilitating. does not usually respond well to typical pharmacologic pain treatments and is common with sever injuries, especially those crushing in nature
intractable pain
durable fibrous material on the outermost layer of the eye
sclera
clear lens on the anterior side of the outermost portion of the eye
cornea
what does the cornea allow for
allows light to enter the eye
the middle layer of the eye consists of this which contains melanin to absorb stray light
choroid
anterior portion of the choroid forms this
ciliary body
smooth muscle fibers of this control the shape of the lens to focus on incoming light
ciliary body
the innermost layer of the eye that contains an outer, pigmented layer and an inner layer consisting of photorecptors and nerve cells
retina
why is the retina vulnerable to damage?
it is weakly attached to the choroid
how many rods do you have in your eye? what do they function in?
about 150 million. they are sensitive to low light and funciton at night
how many cones do you have in your eyes, what do they function in?
about 6 million cones which can operate only in bright light and are responsible for visual acuity and color vision
the axons of the ganglion cells come together at the back of the eye to form this
the optic nerve
transparent, flexible structure that lies behind the iris. smooth muscles attach to it alter its shape and focus on objects. it seperates the eye into two cavties the anterior and posterior chambers
the lens
contains a watery fluid called aqueious humor that provides nutrients to the cornea and lens and carries away cellular waste products
anterior chamber
clear, gelatinous material called vitreous humor fills this.
vitreous humor
what gives the eye its shape
pressure exerted by the aqueous and vitreous humors
how do we hear a sound?
sound waves vibrate the tympanic membrane and the vibrations are transmitted from the membrane to the ossicles (bones). tympanic membrane vibrations cause the malleus to rock back and forth which causes the incus to vibrate and then causes the stapes to move in and out against the oval window. movement of the oval window causes fluid within the cochlea to vibrate creating waves thtat are detected by the organ of corti which stimulate hair movement which causes the dendrites to form nerve impulses that travel to the brain via the vestibulocochlear nerve, cranial nerve VIII
three ring-like, fluid-filled structures that house receptors for body position and movement
semicircular canals
what does opening the Eustachian tube do?
allows air to flow in and out of the middle ear, equalizing intradermal and external pressures on the tympanic membrane
what are nursing diagnoses that are appropriate for sensory disorders?
altered sensory perception and risk for injury
are congenital conditions with the eye common? what do most present with? do they happen by theirselves?
they are rare. they usually present with some form of vision impairment and they are often associated with other disorders
involve a clouding of the lens that is present at birth and results in hazy vision
congenital cataracts
what have congenital cataracts been associate with?
several genetic and chromosomal conditions as well as intrauterine infection exposure
what are clinical manifestations of congenital cataracts?
clouding of the lens, failure of the affected infant to demonstrate visual awareness, the presence of nystagmus
rapid, involuntary back-and-forth eye movement
nystagmus
what do congenital conditions affecting the ears usually result from?
an absence or malformation of the external ear which may or may not affect hearing
absence of the auricle
anotia
underdevelopment, small auricle
microtia
who are congenital ear defects common in, and what other conditions do they usually present with?
they are more common in males and are often associated with other congenital conditions affecting the head
can occur because of damage associated with maternal rubella and syphilis infection during pregnancy
congenital hearing loss
what happens to the senses during aging?
in general they become less acute and less able to distinguish detail. aging increases the threshold to perceive sensory input, so the amount of sensory input needed to be aware of the sensation becomes greater
when do age related eye changes begin? what are they?
as early as 30, such changes include less tear production as well as structural deteriorations. the cornea becomes less sensitive so injuries may go unnoticed. by age 60 pupils decrease to about 1/3 the size at 20, pupil may react more slowly, lens becomes yellowed, less cloudy, and less flexible, fat pads supporting the eye decrease and they eye sinks back into the skull, eye muscles weaken, visual acuity may decrease
what is the most common eye problem associated with aging?
difficulty focusing the eyes - presbyopia
why may night driving be hard when aging?
intolerance to glare as well as difficulty adapting to darkness and brightness may be experienced
what changes occur with the ears with aging?
all of the ear structures thicken and change with aging, affecting balance and hearing especially in regard to high frequency sounds
hearing loss with age is accelerated in what people?
people who were exposed to excessive noise and smoking when they were younger
age-related hearing loss
presbycusis
hearing acuity may decline slightly beginning at what age? why?
about 50 possibly caused by changes in the auditory nerve, and because the brain may have a slightly decreased ability to translate sounds into meaning. impacted cerumen is also a common reason for hearing loss with age
involves damage to the inner ear, auditory nerve, or the brain
sensorineural hearing loss
when an individual has problems transmitting sound through the outer ear and middle ear to the inner ear
conductive hearing loss
persistent abnormal ear noise described as a ringing, buzzing, roaring, or humming sound and is usually a result of mild hearing loss
tinnitus
what can infectious and inflammatory sensory disorders result from? are they acute or chronic? do they resolve with treatment?
can result from a wide range of causative agents. may be acute or chronic, and usually resolve with treatment
what is the main cause of infectious and inflammatory disorders of the eye
usually bacteria and viruses, but may also be caused by trauma, allergies, and irritants
what can severe or untreated infections of the eye lead to?
visual impairment
refers to an infection or inflammation of the conjunctiva. may be caused by viruses, bacteria, chemical irritants, allergies, and trauma
conjunctivitis (pink eye)
regardless of the cause, what are the manifestations of conjunctivitis? what are they for viruses? bacteria? allergens
edema, blurry vision, photobia, and pain. viral infections usually produce a watery or mucuslike exudate. bacterial infections usually produce a yellow-green exudate. allergens and irritants usually produce redness, itching, and excessive tearing.
what are risk factors for developing conjunctivitus?
wearing contacts as well as using contaminated makeup or opthalmic medications
are bacterial and viral causes of conjunctivitis contagious?
yes, they are highly contagious through direct contact
an inflammation of the cornea that can be triggered by an infection (usually viral) or trauma.
keratitis
this can be self-transmitted from the mouth and may cause an ulcerated form of keratitis.
herpes simplex type 1
what are manifestations of keratitis?
severe pain, erythema, drainage, excessive tearing, photobia, and visual disturbances
what are infectious and inflammatory disorders that affect the ear usually caused by? what are they classified based on? do they resolve with treatment?
usually caused by bacteria or viruses, classified based on the area of the ear infected and typically resolve with treatment
an infection or inflammation of the middle ear common in young children
otitis media
why is otitis media more common in young children?
because the Eustachian tubes are narrower, straighter, and shorter and this decreases the ability to drain fluid from the middle ear adequately. in addition to this, a young child’s immune system is less equipped to manage infecitons. adenoid enlargement, usually due to inflammation, can compress the Eustachian tubes
what does otitis media typically begin as?
a viral upper respiratory infection, so it is more common in the winter months
what can happen during viral infections causing otitis media?
the viral infection travels to the middle ear where it causes fluid accumulation behind the tympanic membrane which then creates the perfect medium for bacterial growth
what are additional risk factors for the development of otitis media?
child care in group settings, feeding infants in the supine position, environmental smoking exposure, pacifier use, a history of allergic rhinitis, and the presence of orofacial deformities
what can otitis media lead to?
rupture of the tympanic membrane, scar tissue formation, conductive hearing loss, can spread to nearby structures and cause mastoiditis, cholesteatoma, meningitis, and osteomyelitis
what are manifestations of otitis media?
when present, they include: ear pain, crying or irritability, rubbing or pulling at the ear, mild hearing deficits, sleep disturbances, red bulging tympanic membrane, indications of infection, purulent or clear exudate from the external ear canal, nausea, vomiting, diarrhea, headache
an infection or inflammation of the external ear canal or auricle, usually bacterial in origin but may also be fungal
otitis externa
what does otitis externa generally arise from?
moisture in the ear that creates an environment for bacterial or fungal growth or introduction of the organism from external sources
what are risk factors for the development of swimmers ear?
swimming in contaminated water, scratching the outside or inside of the ear, and insertion of foreign objects
if not treated, what can swimmers ear lead to?
hearing loss, cellulitis, necrosis, osteomyelitis, meningitis
what are manifestations of otitis externa?
ear pain that worsens with auricle movement, prurulent exudate, pruritis, a sensation of fullness in the ear, and hearing deficits
what are the most common manifestations of trauma to the eyes?
eye pain, edema, blurry vision, diplopia, dry eyes, photobia, floaters, pupil dilation, and pupils that are unresponsive to light
what can eye trauma be caused by? ear trauma?
eye trauma - direct physical trauma or chemicals
ear trauma - direct physical trauma and excessively loud noise
what are clinical manifestations of ear trauma
bloody or clear exudate, tinnitus, dizziness, ear pain, hearing deficits, nausea, vomiting, edema and a sensation that there is an object in the ear
group of eye conditions that lead to damage to the optic nerve, often caused by increased intraocular pressure, but can also result from decreased blood flow to the optic nerve
glaucoma
why do pressures in the eye climb with glaucoma? why does this cause decreased blood flow to the optic nerve?
pressure climb inside the eye because of blocked outflow of aqueous humor or increased production of aqueous humor. these increased pressures cause ischemia and degeneration of the optic
what are the four types of glaucoma?
open-angle (chronic) glaucoma, closed-angle (acute) glaucoma, congenital glaucoma, secondary glaucoma
most common type of glaucoma. intra ocular pressure increases gradually over an extended period of time
open-angle glaucoma
what are risk factors for open-angle glaucoma?
family history and being african american
what are clinical manifestations of open-angle glaucoma
painless, insidious, bilateral changes in vision. this can often be overlooked as presbyopia
medical emergency, sudden blockage of aqueous humor outflow that can be caused by trauma, sudden pupil dilation, prolonged pupil dilation, and emotional stress, it is typically unilateral
closed-angle glaucoma
what are clinical manifestations of closed-angle glaucoma?
normally sudden in onset and worsen quickly. severe eye pain, headache, nausea, vomiting, a nonreactive pupil, erythema, haziness of cornea, and vision changes
type of glaucoma present at birth. results from abnormal development of outflow channels of the eye. X-linked recessive. may go unnoticed for a few weeks after birth
congenital glaucoma
type of glaucoma that is the result of certain medications, eye disease, systemic diseases, and trauma
secondary glaucoma
opacity or clouding of the lens. can occur as a congenital condition or develop later in life. over time, proteins in the lens break down, making the lens cloudy
cataract
what are the risk factors for the development of adult onset cataract
family history, advancing age, smoking, ultraviolet light, exposure, metabolic conditions, eye injury
do cataracts affect the eyes symmetrically?
may effect one or both eyes and do not necessarily affect the eyes symmetrically
what are clinical manifestations of cataracts?
cloudy, fuzzy, foggy, or filmy vision; color intensity loss, diplopia, impaired night vision gradually progressing to impaired day vision, halos around light, photosensitivity, frequent changes in eyeglasses or contact prescription
