Special Senses Flashcards
Each eye is surrounded by ________ fat.
periorbital
The _______ nerve is on the posterior surface of the eye.
optic
The eye consists of 3 tunics or layers. From outermost to innermost, these are…
- sclera
- choroid
- retina
In the front of the eye, observe the normally transparent ______.
cornea
The dark _______ is on the edge of the cornea.
conjunctiva
The nerve bundle projecting from the posterior of the eyeball
Optic nerve
These have been cut short during the preparation of the eye dissection.
Extrinsic eye muscles (6)
The white/gray outer layer of the eye (fibrous tunic)
sclera
The clear, anterior portion of the fibrous tunic
Cornea
The pigmented region under the cornea
Iris
The hole between the iris.
Pupil
(More round in the human eye, more oblong in the cow eye)
The thin epithelial/mucous membrane covering the surface of the eye and extending to line the inner eyelid.
Conjunctiva
The thick fluid filling the posterior compartment.
Vitreous humor
A solid oval of translucent tissue
Lens
A ring of ridges around the outside of the iris’ margin.
Ciliary body
A thin film of gray matter loosely attached to the inside posterior wall of the eyeball
Retina
The pigmented region/tunic between the retina and sclera.
Choroid
In some mammals but not in humans, an iridescent _____ can be seen in the choroid.
tapetum lucidum
The oval opening in the iris
Pupil
The ring of short _________ attached the lens to the ciliary body.
suspensory ligaments
The sharpness of the visual image
Visual acuity
Visual acuity is assessed using the…
Snellen eye chart
(Note the lowest row that can be read accurately)
Abnormal curvature of the cornea
Astigmatism
Astigmatism is assessed using the…
Astigmatism test chart
(Cover one eye and stare at the center of the chart. If all lines radiating appear to be straight and of equal darkness, no astigmatism is present.)
The blind spot is usually the ________, a point where there are no photoreceptors in the retina.
optic disc
The ability to adjust the focusing apparatus to account for changes in the distance from the viewed object.
Accommodation
As we age, the ability of the lens to accommodate decreases, making it difficult to focus near vision. This condition is called…
presbyopia
The medial movements of the eyes to focus on a near object
Convergence
In humans, each eye sees a slightly different visual field, resulting in two-eyed vision.
Binocular vision
The different visual fields are integrated in the visual cortex in the brain to provide us with ______.
depth perception
The inability to distinguish certain colors.
Color blindness.
(The most common form is red-green color blindness.)
The ear is divided into 3 areas:
- external ear
- middle ear
- inner ear
The external ear has a cartilaginous flap, the ______, which collects sound waves and directs them into the middle ear, and ultimately the inner ear.
pinna (auricle)
One of the most common infections in children. Inflammation and fluid exudate in the middle ear cavity which produces pressure and pain on the eardrum, and a reduction in movement of the ear ossicles.
Otitis media
______ involved outer or middle ear defects. Sound waves are not transmitted to the inner ear where sound transduction occurs. Hearing aids can improve hearing because bone conduction transmits the sound into the inner ear.
Conduction deafness
____ involves a defect or damage in the inner ear where sound transduction occurs or in the auditory nerve. It can be congenital or acquired and involves the organ of Corti or the cochlear nerve.
Sensorineural deafness
Obtain 3 tuning forks and see which frequency was heard most clearly and comfortably
Frequency range of hearing
A test for unilateral deafness, but can’t identify the type of hearing loss.
Weber Test
If sound is louder in one ear, the ______ test needs to be performed to distinguish conduction vs. sensorineural deafness.
Rinne
In a normal ear, air conduction is better than…
bone conduction
If no sound is experienced, ______ may exist
nerve deafness
If hearing is normal, the sound (from air conduction) will be heard again and will typically last twice as long as bone conduction
Positive Rinne Test
If there is possible conductive impairment, the sound will not be heard
Negative Rinne Test
For unilateral _________ deafness, the sound is heard loudest in the normal ear because the impaired ear is not effective at picking up sounds even if transmitted directly to bone
sensorineural
You perform the Weber Test on a patient and they say the sound is louder in their left ear. You follow up with a Rinne test. In both ears, the Rinne test is positive. What is your diagnosis?
Sensory neural deafness in the right ear.
