Friday 4 May 2012

VISUAL AND AUDITORY 01 - NCLEX REVIEW

  Visual and Auditory Systems
What are the 8 components of the external structure of the eye?
Eyelids, eyebrows, eyelashes, lacrimal system, conjunctiva, cornea, sclera, and extraocular muscles.
What are the 5 internal structures of the eye?
Iris, lens, ciliary body, choroid and retina.
Where does the visual information refracted onto the retina get processed as an image?
The occipital cortex
What makes up the outer layer of the eyeball?
The sclera and the cornea
What is the middle layer of the eyeball called and what is in it?
It is the uveal tract and is made up of the iris, choroid body and ciliary body.
What makes up the innermost layer of the eyeball?
The retina
Where is the anterior chamber of the eyeball located?
Between the iris and the posterior surface of the cornea.
Where is the posterior chamber of the eyeball located?
Between the anterior surface of the lens and the posterior surface of the iris
What does the anterior and posterior chambers of the eyeball contain?
Aqueous humor secreted by the ciliary body
Where is the vitreous cavity located?
Behind the lens and retina
What structures does light pass through in order to reach the retina?
The cornea, aqueous humor, lens and vitreous.
What structure of the eye is most responsible for the majority of light refraction needed for clear vision?
The cornea
What is the function of aqueous humor?
It bathes and nourishes the lens and endothelium of the cornea.
What is glaucoma?
Excess production or decreased outflow of aqueous humor that increases the intraocular pressure above normal (10 mm-21 Hg).
What structures support the ocular lens and keep it in place?
Zonules
What is the function of the ocular lens?
To bend light rays, allowing them to fall on the retina.
Accommodation, a process that allows a person to focus on near objects, is possible through modification of the lens shape. The ________ are the structures that make this occur.
Zonules
Vitreous becomes more ___________ with aging.
Liquid (it is normally a gelatinous substance)
Light passing through the vitreous may be blocked by any ___________ within the vitreous.
Nontransparent substance
__________ is the ability of the eye to bend light rays so they fall on the retina.
Refraction
What is emmetropia?
It means that light is refracted and focused exactly on the retina
What is a refractive error?
When light isn't focused properly on the retina (in front of it, behind it, etc.)
What is myopia?
Near-sightedness
What is hyperopia?
Farsightedness
__________ is caused by an uneveness of the cornea, which results in visual distortion.
Astigmatism
__________ is a form of hyperopia that occurs as a normal process of aging, usually around 40.
Presbyopia
Images refracted on the left side of BOTH eyes form the (left or right?) optic tract and travel to the (left or right?) occipital cortex.
Left optic tract, left side of the occipital cortex
Images refracted on the right side of BOTH eyes form the (left or right?) optic tract and travel to the (left or right?) occipital cortex.
Right optic tract, right side of the occipital cortex
Describe the path of an image through the visual pathway...
Eye, optic nerve, optic chiasm, optic tract, optic radiation, to the occipital lobe (visual cortex)
What crosses over at the optic chiasm?
The visual fibers closest to the nose cross over to the other side, allowing for only the images on the left side of the eye to travel one optic tract and the images on the right side of the eye to travel down another.
Where does the optic chiasm terminate?
At the lateral geniculate body
How are the locations of abnormalities of nerve fibers of the eye determined?
By the interpretation of specific visual field defects. Location of a lesion in the visual pathway determines the resulting visual defect.
What external structures protect the eye?
The eyelids, eyelashes, eyebrows, the surrounding bony orbit and fat pads located below and behind the globe (eyeball).
Where do the upper and lower eyelids join?
At the medial and lateral canthi.
What are the purposes of blinking?
It distributes tears over the eyeball and controls the amount of light entering the visual pathway
How many times does a person blink in a minute?
15
Eyelids open and close through actions of muscles innervated by CN _____, which also helps hold the eyelids against the eyeball.
VII-facial nerve
The ________ is a transparent mucous membrane that covers the inner surfaces of the eyelids and extend over the sclera to form a pocket under each eyelid.
Conjunctiva
The palpebral conjunctiva covers the _______ of the eyelids.
Inner surfaces
The _______ conjunctiva covers the sclera.
Bulbar
What do glands of the conjunctiva secrete?
Mucus and tears
The ________ is composed of collagen fibers meshed together to form an opaque structure referred to as the white of the eye.
Sclera
The ______ forms a tough shell of collagen fibers that helps protect the intraocular structures of the eye.
Sclera
What are the five layers of the cornea?
The epithelium, Bowman's layer, the stroma, Descemet's membrane, and the endothelium.
The stroma of the cornea is comprised of ______.
Collagen fibrils
What are the components of the lacrimal apparatus?
The lacrimal glands and ducts, lacrimal canals and puncta, the lacrimal sac and the nasolacrimal sac.
What are the extraocular muscles of the eye?
The superior and inferior rectus muscles, the medial and lateral rectus muscles, and the superior and inferior oblique muscles.
_______ movement is a simultaneous movement of two structures in the same direction, as with the eyes.
Conjugate
What is the pathway of tears produced in the lacrimal apparatus?
The tears pass over the surface of the eye and enter the lacrimal canal. The tears travel through the lacrimal sac and then into the nasolacrimal duct to the nasal cavity.
The ______ provides the color for the eye.
Iris
The pupil of the iris constricts via action of the iris sphincter muscles which is innervated by CN _____ and dilates via the action of the iris dilator muscle that is innervated by CN ______.
Constricts= CN III-oculomotor nerve Dilates = CN V-trigeminal nerve
The _____ is a biconvex, avascular, transparent structure located behind the iris.
Lens
The _______ is a highly vascular structure that serves to nourish the ciliary body, iris and the outer portion of the retina.
Choroid
The _______ is the innermost layer of the eye that extends and forms the optic nerve. It is mostly made of neurons.
Retina
Blepharo-dermachalasis is a condition seen in elderly patients that presents as...
Excessive upper eyelid skin
Small yellowish spots located on the medial aspect of the conjunctiva are called...
Pinguecula
What color are the sclera in the elderly population?
Yellow from lipid deposition (usually they are bluish)
A milky or yellow ring encircling the periphery of the cornea is called...
Arcus senilis
What causes arcus senilis?
Cholesterol deposits in the peripheral cornea
A thickened, triangular bit of pale tissue that extends from the inner canthus of the eye to the nasal border of the cornea is called...
Pterygium
What causes Pterygium?
Tissue damage of the cornea related to chronic exposure
Elderly people experience decrease of water content in the eye and atrophy of nerve fibers of the cornea. This results in...
Decreased corneal sensitivity and corneal reflex
Accumulation of lipid deposits in the cornea results in _________ of vision.
Blurring
As ciliary muscles become smaller and stiffer with age, what happens to a person's vision?
They have a decrease in near vision and accommodation
Biochemical changes in lens proteins, oxidative damage, and chronic exposure to ultraviolet light leads to the development of _________ with advancing age.
Cataracts
Age related macular degeneration as a result of vascular changes leads to a loss of ________ vision.
Central
Liquefaction and detachment of the vitreous leads to the phenomenon known as...
Floaters in the visual field.
________ are the photoreceptor cells that are stimulated in dark or dim environments.
Rods
________ are the photoreceptor cells that are receptive to colors in bright environments.
Cones
Which part of the retina provides for the sharpest visual acuity?
The fovea centralis (composed of ONLY densely packed cones)
The ________ is the part of the retina that is relatively free of blood vessels and has a high concentration of cones.
Macula
Which systemic diseases that can potentially impact ocular health should a nurse specifically ask about during a health assessment?
Diabetes, hypertension, Cancer, Rheumatoid Arthritis, Syphilis and other STDs, AIDS, muscular dystrophy, myasthenia gravis, MS, inflammatory bowel disease, hypothyroidism and hyperthyroidism (they all can impact vision).
Why is it important to determine if a client has had a history of cardiac or pulmonary disease when conducting a health history to ascertain the cause of eye problems?
Glaucoma is often treated with Beta-adrenergic blockers which could cause a slow heart rate, decrease blood pressure and exacerbate asthma or emphysema.
Which eye conditions should a nurse inquire about during a visual health history?
Strabismus, amblyopia, cataracts, retinal detachment, refractive surgery, glaucoma and/or any eye trauma.
Surgeries and/or trauma on the ________ can be significant when gathering health history data for an eye exam.
Head
Some cold medicines can cause pupils to _________.
Dilate
Antihistamines and decongestants are drugs that can cause ocular ________.
Dryness
Related to the eyes, corticosteroids, thyroid medications, and hypoglycemic medications can contribute to the development of ______________.
Cataracts and glaucoma
Why is a history of brain surgery in a client important to know when doing a visual health history?
Brain surgeries can result in swelling which puts pressure on the optic nerve or tract, resulting in visual disturbances.
Which populations have a higher risk of damage to the optic nerve from glaucoma?
African Americans and older people
What family history data is important to gather during a health assessment focused on the eyes?
Family history of: Atherosclerosis, diabetes, thyroid diseases, hypertension, arthritis, cancer, cataracts, tumors of the eye, refractive errors (especially myopia and hyperopia), or retinal degenerative conditions (like macular degeneration, retinal detachment, retinitis pigmentosa).
Adequate intake of vitamins ______ & _______ may be beneficial in preventing or delaying retinal damage.
C & E
Deficiencies in _______ have been linked to the development of erythematous scales in the periorbital area of the eye.
Zinc
Why is it important to assess a client's elimination pattern during an eye exam?
Straining to poop increases intraocular pressure (Valsalva maneuver). If the client needs eye surgery, this may be a concern.
What is hyphema?
Intraocular bleeding
Cross-country skiers can develop corneal ________ after an abrasion from low-lying tree limbs. Assessing leisure activities can help identify these types of conditions.
Fungal ulcers
Lack of sleep can cause ocular _______, especially in those who wear contact lenses.
Irritation
What common eye conditions can present with pain?
Corneal abrasions, iritis, acute glaucoma, infections and the presence of foreign bodies
What is involved in an objective physiologic functional eye assessment?
Visual acuity, ability to judge closeness and distance, extraocular muscle function, evaluating visual fields (confrontation), pupil function (accommodation) and intraocular pressure.
During your visual assessment of a client for an eye exam, you notice that they hold their head in an unusual position. You suspect they might be suffering from what type of visual disturbance?
Diplopia (double vision)
You are collecting information for a client's health history prior to an eye exam and you notice that he is covering his eyes while talking to you. You automatically suspect he has...
A corneal abrasion (which makes him sensitive to light), or photophobia.
You go to shake the client's hand before leaving the room to talk to the doctor. He pauses a moment, and slightly misses your hand, corrects and finally shakes it. What part of his vision might he be having problems with?
Depth perception (although this would be a crude assessment of it)
Related to a vision assessment, the nurse must document the patient's ________ before they receive any care for medical and legal reasons.
Visual acuity
OD is the abbreviation for...
Right eye (Oculus Dexter)
OS is the abbreviation for...
The left eye (Oculus Sinister)
OU is the abbreviation for...
Both eyes (Oculus uterque)
The Snellen chart is used to measure...
Visual acuity
_________ is defined as the best-corrected vision in the better eye of 20/200 or less.
Legal blindness
The Jaeger chart is used to measure...
Near vision
You read in a patient's chart: Visual Acuity FC/ 2ft. OU. What does this mean?
The patient could only count the nurse's fingers (FC=finger count) at the distance of 2 ft. or closer for both eyes (OU).
You read a patient's chart and it reads: Visual Acuity HM OU. What does it mean?
The patient could only indicate sensing a moving hand (HM=Hand Movement) when it was waved in front of their face for both eyes (OU).
When should a nurse test Near acuity as well as Visual acuity?
When the client complains of near vision problems or if they are over the age of 40.
How far away is a Jaeger chart held away from the patient?
14 inches
What is a normal finding for Near Acuity testing?
J1, which means the client can read 4 pt. font at 14 inches.
What does a J10 Near Acuity mean?
The client can read 14 pt. font at 14 inches/moderately impaired near vision.
If you don't have a Jaeger chart but need to assess near vision, how could you do it?
Hand them a newspaper and measure the distance from their eyes for them to comfortably read it. It would be documented as, Reads newspaper headline at ____ inches/cm.
How is extraocular muscle function evaluated? (2)
Darken the room, shine a light directly on the cornea. It should be reflected in the same place in both eyes (the center). To test movement, hold your finger about 10-12 inches away from their nose and have the client follow it through the 6 cardinal positions.
Having a client track your finger through the six cardinal positions can indicate paralysis/weakness of what cranial nerves?
CN III (oculomotor) CN IV (trochlear) CN VI (abducens)
What is anisocoria?
Unequal pupil size, in a small percentage of the population this is a normal finding (usually it's not normal).
How is pupil function tested?
Shining a light in a client's eyes and looking for a reaction to light that is equal in size, round and brisk both directly and consensually (one reacts, so does the other).
PERRLA/PERLA means...
Pupils Equal, Round, Reactive to Light and Accommodating
What does a Tono-pen measure?
Intraocular pressure
How is intraocular pressure usually measured?
The cornea is anesthetized and touched lightly with a Tono-pen several times to get several measurements.
What is a normal intraocular pressure measurement?
10-22 mm Hg
The structures that constitute the visual system can be assessed primarily through __________.
Inspection
What eye structures can be visually assessed through the cornea and pupil openings?
Iris, lens, vitreous, retina and optic nerve
You are assessing an infant's sclera and notice there is a slightly bluish cast to it. You know this means...
Nothing, this is a normal finding in infants (they have naturally thin sclerae).
You are assessing an older adult's sclera and notice a slightly bluish cast. You know that this means...
Nothing, scleral thinning is a common event in older adulthood.
You are assessing an older adult's sclera and notice it is yellowish. You know this is caused by...
Lipid deposits and is a normal finding
You are assessing an African American man in his twenties and notice while observing his sclera that it is slightly yellow. You know that...
For African Americans and Native Americans this is a normal finding.
What is a normal finding for a visual inspection of the cornea?
It should be clear, shiny and transparent. No blood (duh!) or discharge.
What is a normal finding for the optic disc/nerve?
Creamy yellow with distinct margins, although there may be some blurring nearing the nasal margin (side closest to the nose). An indentation called the physiologic cup should be no more that 1/2 the diameter of the disc.
The background of the retina is referred to as the _______.
Fundus
You are looking at the retinal fundus and see small dots and areas that look like flames. You know these are...
Hemorrhages and they can be associated with hypertension or diabetes.
The ________ test is a tool used to detect color blindness.
Ishihara
Older adults tend to lose color discrimination at the _______ end of the color spectrum and loss of sensitivity to the entire color spectrum, particularly when _______ are present.
Blue end Cataracts
___________ vision allows a patient to see objects in three dimensions.
Stereoscopic
Any event that causes a patient to have monocular vision (seeing out of one eye) results in the loss of ________ vision.
Stereoscopic
A doctor tells you a client is positive for stereopsis. You know this means...
That they can see out of both eyes...(binocular vision) what a booger to use big words!
A client has to wear a patch for several weeks after undergoing eye surgery. You know that their ability to judge ________ will be impaired.
Distances/depth perception. Can result in difficulty walking/driving, etc.
A client complains that their eye feels like something is stuck in there. What are some conditions that could cause this sensation?
Corneal erosion or abrasions, trauma, wearing contact lenses, or something really is stuck in there (foreign body)
A client comes in and complains that the light is killing their eyes. What ocular conditions do you suspect?
Inflammation/infection of the cornea, or inflammation/infection of the uveal tract (iris/ciliary body)
A client complains of a deep, throbbing and severe pain in their eye. They are also extremely nauseous and report throwing up at home. You suspect...
Acute glaucoma
A client complains of a deep, throbbing, severe pain in their eye. You suspect what ocular conditions?
Anterior uveitis, acute glaucoma (usually nausea/vomiting with this one), or infection.
A client comes in complaining of blurred vision. You tell them several ocular conditions need to be investigated, including...
Refractive errors, corneal opacities, cataracts, migraine aura, and retinal changes (detachment, degeneration, etc.)
A client comes in and says they see spider webs in their field of vision. You tell them this is caused by...
Most commonly, vitreous liquefaction (age related). Sometimes caused by retinal holes, tears or hemorrhage into the vitreous.
A client comes in complaining of double vision. You know this is caused by an abnormality in extraocular muscles related to ____________ pathology.
Muscle or Cranial Nerve
Hordeolum is another word for what eye condition?
A sty (superficial white nodule/infection of a sebaceous gland of the eyelid)
What organism is the most likely culprit for development of a sty/hordeolum?
Staphylococcus aureus
Blepharitis is often a chronic, bacterial infection of the _________. It produces redness, crusting and swelling.
Eyelid
_________ is a drooping of the upper lid margin. It can be myogenic in cause (myasthenia gravis for example) or caused by a tumor or excessive skin.
Ptosis
The inward turning of an upper or lower eyelid margin is called...
Entropion
The outward turning of the lower lid margin can be caused by eyelid tumor, herniated orbital fat or extravasation of fluid and is called...
Ectropion
What causes conjunctivitis?
It can be caused by bacteria, viruses, allergies or a chemical irritation
You are conducting a visual inspection of a client's sclera and you notice small blood spots on the sclera. You know this is called...
Subconjunctival hemorrhage, caused when conjunctival blood vessels rupture
How can a corneal abrasion be visualized?
Through the use of fluorescein dye
What conditions can cause exophthalmos?
Hyperthyroidism, intraocular or periorbital tumors
A client has uneven, constricted pupils. What is this called, and what causes it?
Anisocoria, is usually caused by CNS disorders. In a small percentage of the population it is a normal finding.
What should a nurse suspect if a client has an abnormal pupillary response to light, or abnormal accommodation?
A CNS disorder. Note: General anesthesia can temporarily cause these abnormalities.
An overaction or underaction of extraocular muscles presents as...
Strabismus (deviation of the eye in one or more direction)
A client calls you and says she has lost her peripheral vision and is wondering what could be happening. You know that she could be suffering from what visual abnormality?
Glaucoma, interruption of the visual pathway (like a tumor), or a migraine.
A client comes in with her daughter, who is guiding her through the waiting room and into the examination room. The client indicates she has no central vision. You know the first thing to look for would be...
Macular degeneration
What conditions can cause cataracts?
Aging, trauma, diabetes, or long-term systemic corticosteroid therapy
What makes up the peripheral auditory system?
The external, middle and inner ear.
The peripheral auditory system is concerned with ________ & ________ of sound.
Reception and perception of sound
What is the function of the inner ear?
Hearing and Balance
What makes up the central auditory system?
The brain and its pathways
What is the function of the central auditory system?
It integrates and assigns meaning to sounds heard
What are the functions of the external and middle portions of the ear?
To conduct and amplify sound waves.
Sound conducted through the external and middle ear is called _________ conduction.
Air conduction
 hearing loss occurs when there's a problem with the middle or external ear. It alters a person's perception of or sensitivity to sound.
Conductive hearing loss
Pathology or damage to the inner ear or its pathway to the brain results in ___________ hearing loss.
Sensorineural hearing loss
________ hearing loss is characterized by a difficulty in understanding the meaning of words that are heard.
Central (impairment within the central auditory system)
What makes up the external ear?
The auricle (pinna) and the external auditory canal, its epithelium and glands
What does the glands of the external ear produce and what is its purpose?
Sebaceous glands produce oil and the ceruminous glands produce wax which together to lubricate the ear canal. This keeps it free of debris and kills bacteria.
The external ear and canal collects and transmits sound to the __________.
Tympanic Membrane
What structure serves as a partition between the external and middle ear?
The tympanic membrane (ear drum)
What is the function of the tympanic membrane?
It serves as a partition and conducts sound transmission between the external auditory canal and the middle ear.
Where is the middle ear located?
It is in an airspace located in the temporal bone.
What makes up the middle ear?
The auditory ossicles (malleus, incus, stapes), the eustachian tubes, and mucous membranes that extend from the middle ear through the eustachian tube to the nasal pharynx, and the oval window.
What is the function of the eustachian tube?
It equalizes air pressure between the middle ear and throat and allows the tympanic membrane to freely move
The eustachian tube opens with _______ & ________.
Yawning and swallowing
Vibrations of the tympanic membrane cause the __________ to move and transmit sound waves to the oval window.
Ossicles
The oval window vibration causes fluid in the inner ear to move and stimulates _________.
The receptors of hearing
What are the functions of the oval window?
Stimulates the receptors of hearing through movement of fluid and maintains fluid balance of the inner ear
What is the upper portion of the middle ear called and what is its function?
The epitympanum, it communicates with air cells within the mastoid bone.
CN ______ is above the oval window of the middle ear. The bony covering can become damaged by chronic ear infections, skull fracture or trauma during ear surgery.
CN VII-facial nerve
Problems with voluntary facial movements, eyelid closure, taste discrimination, can all result from damage to the middle ear and CN _____.
CN VII-Facial (the damage can be permanent, and results from chronic ear infections, fracture or surgical trauma)
The receptor organ for hearing, located in the inner ear, is called...
The cochlea
The cochlea contains the _________, whose tiny ear hair cells respond to stimulation of selected portions of the basilar membrane according to pitch.
Organ of Corti
Which cranial nerve transmits sound to the brain for processing?
CN VIII-vestibulocochlear
Which part of the brain processes and interprets sound?
The temporal lobe
What are the two divisions of the inner ear?
The bony labyrinth which includes the cochlea and the organ of Corti. The second is the basilar membrane which governs hearing. The membranous labyrinth (located within the bony labyrinth) which includes the semicircular canals and the vestibule. It governs balance.
The membranous labyrinth is filled with ________ fluid. The bony labyrinth is filled with _________ fluid.
Membranous-endolympathic Bony-Perilymphatic
What is the function of the endolympathic and perilymphatic fluid located in the bony and membranous labyrinth of the inner ear?
It cushions the structures and communicates with the brain and the subarachnoid spaces of the brain.
What ear problems can cause vertigo?
Debris or excessive pressure within the lymphatic fluid of the inner ear.
Describe the process of the transmission of sound...
Sound waves are detected by the auricles and the auditory canal. They are carried to the tympanic membrane causing it to vibrate. The vibration travels through the malleus, incus and stapes (ossicles). The stapes moves back and forth, and pushes the membrane of the oval window. Waves are produced in the perilymph and the tiny sensory hair cells of the cochlea convert it to a nerve impulse. The impulses are carried by nerve fibers to CN VIII and then to the brain.
Bones of the skull can transmit sound directly to the _______ ear. This is called bone conduction.
Inner
__________ is the term for hearing loss due to aging. It can also be caused by noise exposure, vascular or systemic diseases, poor/inadequate nutrition, ototoxic drugs or pollution.
Presbycusis
What structures are damaged in presbycusis?
The hair cells of the organ of Corti and/or lymph-producing cells are atrophied. Ossicles are calcified.
_________ is an auditory abnormality that may accompany hearing loss resulting from the aging process.
Tinnitus (ringing in the ears)
Problems with balance may manifest as _______ or ______.
Nystagmus or Vertigo
________ is abnormal eye movements that may be observed by others as twitching of the eyeball or described by the patient as a blurring of vision with head or eye movement.
Nystagmus
__________ is a sense that the person or objects around the person are moving or spinning and is usually stimulated by movement of the head.
Vertigo
A sensation of being off-balance that occurs when standing or walking is called ___________.
Dizziness
Dizziness is a sensation that doesn't occur when a person is...
Lying down
T/F Many problems related to the ear are sequelae from childhood illnesses or result from problems of adjacent organs.
TRUE
What is refractometry?
A subjective measure of refractive error. Lenses are mounted on rotating wheels and the patient looks through them and indicates when the acuity improves. This is the common tool used during an eye exam.
________ drugs are used to paralyze accommodation during refractometry. Dilation may last 3-4 hours.
Cycloplegic
A-scan ultrasonography is used to...
Get an axial length measurement for calculating power of an intraocular lens implanted after cataract extraction.

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