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Auditory/Visual DO
Ch 13 Care of Patient with Auditory or Visual Disorders
Question | Answer |
---|---|
equilibrium | sense of balance, linked with hearing |
the eye is how much in diameter? | 1 inch or 2.5 cm |
The eye contains | 70% of the sensory structures in the body |
The optic tracts contain more than | 1 million nervce fibers that carry messages from the eye to the brain |
bones surrounding the eye include | frontal, zygomatic, ethmoid, sphenoid, and lacrimal bone |
accessory structures of the eye include | eyelashes, eyelids, and lacrimal apparatus function mainly as protective structures |
Six extrinsic eye muscles control | gross eye movement and enable the eye to focus on any object in the visual field |
lacrimal apparatus | manufacture and drain tears to keep the eyeball moist and sweep away debris that might enter the eye |
teras are composed of a watery secretion that contains | salt, mucus, and a bactericidal enzyme called lysozyme |
lysozyme | bactericidal enzyme secreted in tears |
lazy eye | involves a weak or elongated eye muscle and is characterized by visual disturbances |
conjunctiva | thin mucus membrane that lines the inner aspect of the eyelids and the anterior surface of the eyeball to the edge of the cornea |
due to irritation or congestion of the conjunctiva | blood vessels can become dilated and cause bloodshot eye look |
eyeball is composed of how many layers or tunics? | three |
outermost layer of the eyeball is | fibrous tunic |
fibrous tunic is composed of | thick, white, opaque, connective tissue called the scelera or the white of the eye |
scelera | aka white of the eye composed of thick, white, opaque, connective tissue |
scelera gives | shape to the eyeball and protects the inner eye structures b/c of its toughness |
cornea | central anterior portion of the sclera |
The cornea is | transparent and covers the iris (colored part of the eye) |
iris | colored part of the eye |
The cornea projects like a | dome beyond the sclera |
The cornea is one of the most | highly developed, sensitive tissues in the body and is innervated by the trigeminal nerve (CNV) |
canal of Schlemm is located where? | special structure located at the junction of the sclera and cornea |
canal of Schlemm is a | tiny venous sinus at the angle of the anterior chamber of the eye |
canal of Schlemm drains | the aqueous humor and funnels it into the bloodstream |
canal of Schlemm aids in controlling | intraocular pressure (the pressure within the eyeball) |
vascular tunic | middle layer of the eyeball |
vascular tunic contains | the choroid, the ciliary body, and the iris |
choroid | posterior portion of the vascular tunic |
pupil | circular opening located slightly nasal to the center of the iris |
The iris lies between | the cornea and the lens |
The iris regulates | the amount of light entering the eye through the pupil much like a camera lens |
retina | the innermost tunic of the eye |
The retina is | a 10 layer delicate, nervous-tissue membrane of the eye that receives images of external objects and transmits impulses |
rods and cones (photoreceptors) are located | specialized sensory cells located within the retina |
rods and cones (photoreceptors) are | scattered throughout the retina except where the optic nerve exits the eye |
optic disk | aka blind spot, where the optic nerve exits the eye |
Rods are | receptors for night vision and are responsible for peripheral vision |
Cones are | responsible for day vision |
There are how many kinds of cones? | three, each sensitive to a different color, red, green or blue |
fovea centralis | the center of the retina |
the fovea centralis | is a pinpoint depression composed only of densely packed cones, provides sharpest visual acuity |
macula | surrounds the fovea |
the macula is | an area of less than 1 mm2 that has a high concentration of cones and is relatively free of blood vessels |
Vitamin A is responsible for | the production of the color pigments (cones) |
absence of these types of cones cause | color blindness inherited condition found mainly in males |
crystalline lens | transparent, colorless structure that is bioconvex in shape, enclosed in a capsule, and held in place behind the pupil by the suspensory ligament |
The eye is divided into two chambers by the | crystalline lens |
The function of the crystalline lens is to | focus light rays so that they form a perfect image on the retina |
Anterior to the crystalline lens is the | anterior chamber that is filled with aqueous humor |
aqueous humor | a clear watery fluid similar to blood plasma |
Aqueous humor also helps maintain | the shape of the eyeball, keeps the retina attached to the choroid, and refracts light |
vitreous humor | a transparent jellylike substance that gives shape to the eyeball, keeps the retina attached to the choroid, and refracts light |
How are aqueous humor and vitreous humor differ how? | the aqueous humor is continually replaced and the vitreous humor is not |
4 basic processes necessary to form images are | refraction, accommodation, constriction, and convergence |
refraction | light rays are bent as they pass thru the colorless structures of the eye, enabling light from the environment to focus on the retina |
accommodation | the eye is able to focus on objects at various distances; able to focus the image of an object on the retina by changing the curvature of the lens |
constriction | the size of the pupil, which is controlled by the dialator and constrictor muscles of the iris, regulates the amount of light entering the eye |
convergence | medial movement of both eyes allows light rays from an object to hit the same point on both retinas |
pinna or auricle | external ear |
equilibrium | balance |
The external and middle ear deal exclusively with | sound waves |
Inner ear deals with | sound waves and equilibrium |
The external ear is composed of | the auricle (pinna), the external auditory canal, and the tympanic membrane (eardrum) |
tympanic membrane | aka eardrum; a thin transparent membrane |
external auditory canal | aka meatus |
external auditory canal or meatus is a | 1 inch tube (2.5 cm) that ends at the tympanic membrane |
The external auditory canal (meatus) contains | cilia and specialized sebaceous (oil) glands called ceruminous glands |
ceruminous glands | specialized sebaceous (oil) glands that secrete cerumen (earwax) which protects the inner lining from infection |
cerumen | earwax that protects the inner lining from infection |
the cilia and cerumen also prevent | foreign objects from entering the ear |
tympanic cavity | aka middle ear; is a small, air-filled chamber located within the temporal bone |
eustatian tubes | aka auditory canals |
eustatian tubes are lined with | mucous membrane that joins the nasopharynx and the middle ear cavity |
eustatian tube does what? | equalizes the air pressure on either side of the tympanic membrane |
Because the pharynx, eustatian tube, and middle ear are all covered with a continuous mucous membrane | infection can travel very easily from the throat to the middle ear; seen in young children often |
the posterior wall of the middle ear opens into the | mastoid process, an area filled with air spaces which also aids in equalization of air pressure |
ossicles | three small bones extending along the middle ear chamber |
ossicles do what? | carry sound waves from the external ear to the inner ear |
Ossicles are named according to | shape; malleous (hammer), incus (anvil), stapes (stirrup) |
malleus | hammer shaped |
incus | anvil shaped |
stapes | stirrup shaped |
movement of the stapes against the oval window causes | movement of fluid into the inner ear |
oval window | a small membrane that marks the beginning of the inner ear |
The most important part of the ear is | the inner ear or labyrinth |
labyrinth | a series of canals in the inner ear composed of bony labyrinth and membraneous labyrinth |
perilymph | a fluid filling the bony labyrinth that contains 3 subdivisions |
3 subdivisions of the perilymph | semicircular canal, vestibule, and cochlea |
semicircular canal | associated with the sense of balance |
vestibule | oval central portion of the bony labyrinth that contains receptors that respond to gravity |
membraneous labyrinth is a | series of sacs and tubes that contain a thicker fluid called endolymph |
Endolymph and perilymph | conduct sound waves through the inner ear system |
cochlea resembles | a snail's shell and contains the organ of Corti |
organ of Corti | in the cochlea, the organ of hearing that contains many hearing receptors or hair cells |
cochlear nerve | a branch of the eighth cranial nerve, the vestibulocochlear nerve |
Extending upward from the vestibule are | three semicircular canals responsible for maintaining balance and equilibrium |
On the tongue of the average adult, there are approx how many taste buds? | 10,000 taste buds |
sweet | resond to sugar and other sweet substances |
sweet taste buds are located where? | on the tip of the tongue |
sour | respond to acid content foods |
sour taste buds located where? | on the sides of the tongue |
salty | respond to metal ions within foods |
salty taste buds are located where? | on the tip of the tongue |
bitter | respond to alkaline or basic ions within foods |
bitter taste buds are located where? | on the posterior portion of the tongue |
olfactory receptors | receptors for the sense of smell |
olfactory receptors are located where? | in the roof or upper part of the nasal cavity |
Once olfactory nerves are damaged, | the body is not able to regenerate olfactory cells and sense of smell is impaired |
tactile receptors | receptors for touch that respond to touch, pressure, and vibration |
tactile receptors are located where? | throughout the integumentary system |
proprioceptors | sense of position that maintains the proper position of the body |
proprioceptors include | any sensory nerve endings such as those located in the muscles, tendons, and joints |
Shelia will miss | Jason while she is gone! Love you! |