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