Lecture Exam Three: Chapter 15 Flashcards
Which of the following is NOT considered one of the special senses?
touch
What are the special senses?
- vision
- taste
- smell
- hearing
- equilibrium
Special senses are mediated by […] NOT by […].
special sensory receptors; general receptors
Of the following senses, which accounts for the majority of sensory receptors in the body?
vision
How many of the body’s sensory receptors can be found in the eye?
70%
How much of the cerebral cortex is involved in visual processing?
half
Only […] of the eyeball structure is actual visible.
1/6
Which of the following terms is a synonym for eyelids?
palpebrae
Pinkeye is an infection of the […] of the eye.
conjunctiva
In order to turn the eye straight down, the actions of the […] muscle(s) us (are) required.
inferior rectus and superior oblique
Which muscles move the eye laterally. Which cranial nerve controls it?
lateral rectus; abducens
Which muscle elevates eye and turns it medially? Which cranial nerve controls it?
superior rectus; oculomotor
Which muscles move the eye medially? Which cranial nerve controls it?
medial rectus; oculomotor
Which muscles depresses the eye and turns it medially? What cranial nerve controls it?
inferior rectus; oculomotor
Which muscles elevate and turns the eye laterally? Which cranial nerves control it?
inferior oblique; oculomotor
What do you call a tarsal gland cyst?
chalazion
Sty:
inflammation of any of the smaller sebaceous glands in your eyelid
Conjunctivitis:
inflammation of the conjunctiva (red)
Pinkeye:
conjunctival infection caused by bacteria and viruses
Diplopia is also known as […].
double vision
Diplopia:
movements of external muscles of two eyes are not perfectly coordinated
What can cause diplopia?
paralysis, extrinsic weakness, or neurological disorders
Strabismus:
congenital weakness of external eye muscles
Due to strabismus the eye rotates…
laterally and medially
What happens to the deviant eye during strabismus?
no treatment results in the functional blindness
The cornea is actually part of the […] layer of the eye.
fibrous
What are the three layers of the eyeball?
- fibrous
- vascular
- inner
Eye– The internal cavity filled with fluids called […].
humors
Eye– What separates the two cavities?
lens
The ciliary muscle helps to…
control the shall of the lens
Sympathetic fibers innervating the iris of the eye cause which response?
dilation
Parasympathetic fibers innervating the iris of the eye cause which response?
constriction
What are the two pupilaes of the iris?
- sphincter
2. dilator
The place in the retina where the optic nerve leaves is called the […].
optic disk or blind spot
The optic nerve is primarily composed of axons from which nerve cell in the retina?
ganglion cells
Focusing an object on the […] provides the highest visual acuity.
fovea centralis
What is retinal detachmen?
condition where pigmented and neural layers separate allowing jellylike vitreous humor to seep between them
What can retinal detachment lead to?
permanent blindness
When does retinal detachment occur?
during traumatic blow to head or sudden stopping of head during movement
**bungee jumping
Glaucoma is a disorder in which:
there is elevated pressure in the eye that compresses the retina and optic nerve, there is also improper drainage of the aqueous humor
What is the most notable sign of glaucoma?
seeing halos around lights and blurred vision
How is glaucoma deteced?
directing puff of air to measure amount of corneal deformation
What is the treatment for glaucoma?
eye drops that increase rate of aqueous humor drainage or decrease its production (laser therapy or surgery)
Cataract:
clouding of the lens
What can cause cataracts to form?
aging, diabetes, mellitus, heavy smoking, frequent exposure to intense sunlight
What can increase cataract formation?
vitamin c
What is the treatment for cataracts?
lens can be replaced with artificial lens
What is the wavelength of light?
400 and 700 nm
The formation of rainbows reflects the fact that […].
visible light consists of multiple wavelengths of light
Color blindness:
lack of one or more cone pigments
What is the most common type of color blindness?
red-green
A person with defective cones will have trouble […]
distinguishing colors
When all three cone populations are stimulated equally, we see
white
Visual pigments are differentiates based on the identity of the […] protein.
opsin
Refraction:
bending of light rays
Why does refraction occur?
due to change in speed of light when it passes from one transparent medium to another and path of light is at an oblique angle
Convex does what to the light?
bends light
Concave does what to the light?
disperse
Sympathetic innervation is more predominant during […].
distant vision
Far point of vision:
distance beyond which no change in lens shape is needed for focusing
Emmetropic eye is also known as
normal eye
What is the optimal distance for distant vision? Why is this the case?
20 feet
cornea and lens focus light precisely on retina at this distance
Distant vision means the lens shape is…
flat due to the pull on ciliary zonule
Parasympathetic input vs sympathetic input:
p = lens bulges for close vision
s = lens flattens for distant vision
If your Optometrist tells you that your right eye is emmetropic, you will need what kind of lens?
none, eye is normal
Myoptic mean your will need what kind of lens?
concave
**nearsighted
The light-dependent step in vision involves:
stimulating the transformation in retinal from the 11- cis- isomer to the 11-trans-isomer
The detection of light is ultimately communicated to the brain because […].
photoreceptor cell hyperpolarization
How many steps are generally involved in retinal absorption?
5
List the steps for retinal absorption:
- retinal absorbs and changes shape, visual pigment activates
- visual pigment activates transducin (G protein)
- transducin activates PDE (phosphodiesterase)
- PDE converts cGMP into GMP, cause cGMP levels to fall
- cGMP-gated cation channels close, resulting in hyperpolarization
Which cell type determine whether a particular ganglion cell will be “on-center” or “off-center”?
bipolar cell
During light adaption:
we lose retinal sensitivity, but gain visual activity
Rhodopsin is so sensitive that […] occurs even in […].
bleaching; starlight
Nyctalopia:
night blindness; condition in which rod function is seriously hampered
What can cause nyctalopia?
prolonged vitamin A deficiency or retinitis pigmentosa
Retinitis pigmentosa:
- degenerative retinal diseases that destroy rods
2. tips of rods are not replaced when they slough off
Chemoreceptors are used by what two systems?
smell (olfaction) and taste (gustation)
Chemicals must be dissolved in […] to be picked up by […]. Smell receptors are picked up by chemicals dissolved in […] while taste receptors respond to chemicals dissolved in […].
aqueous solution; chemoreceptors; nasal fluids; saliva
The receptive structures for smell are the:
olfactory receptor cells and cilia
In detection of smell, odorants themselves:
bind to receptors and stimulate opening of ion channels
The olfactory receptor G-protein known as Golf probably activates which of the following enzymes?
adenylyl cyclase
Taste is […] smell.
80%
The relationship between smell and taste is evidenced by the fact that both sensations are a type of […].
chemoreception
Where are most taste buds located?
tongue in papillae
Funigiform papillae:
tops of these mushroom-shaped structures house most taste buds; scattered across tongue
Foliate papillae:
on sides walls of tongue
Vallate papillae:
largest taste buds with 8-12 forming “V” at back of the tongue
Few taste buds are located on…
soft palate, cheeks. pharynx, epiglottis
Circumvallate:
lie near the back of the palatine section of the tongue; arranged in a V shaped formation
Umami:
- describes the way glutamate and some nucleotides taste
2. signals nutritious, desirable foods
Name the 5 basic taste sensations:
- sweet
- sour
- salty
- bitter
- umami
Sweet:
sugars, saccharin, alcohol, some AA, some lead salts
Sour:
hydrogen ions in solutions
Salty:
metal ions (inorganic salts); sodium chloride tastes saltiest
Bitter:
alkaloids such as quinine and nicotine, caffeine, and nonalkaloids such as aspirin
Umami:
AA glutamate and aspartate
What is an example of umami?
beef (meat), cheese taste, and monosodium glutamate
The hearing receptors are located in the […].
internal ear
The ear’s three major areas and function:
- external (hearing)
- middle (hearing)
- internal (hearing and equilibrium)
T/F: Receptors for hearing and equilibrium act independently of one another.
true
**respond to different stimuli
Sound wavs are transmitted from the external environment to the middle ear by the […].
acoustic meatus
The middle ear ossicles serve to […] the sound waves onto the oval window.
amplify
Sound waves are transmitted directly into the inner ear by movements of the […].
oval window
The tensor tympani muscle arises from the wall of the pharyngotympanic tube and inserts on the […].
malleus
The […] is part of the membranous labyrinth and therefore is filled with endolymph.
scala media (cochlear duct)
Hearing:
reception of an air sound wave converted to a fluid wave
What do sound waves stimulate?
mechanosensitive cochlear hair cells
Sounds:
pressure disturbance produced by a vibrating object and propagated by molecule of the medium (air)
The […] of sound waves is interpreted as differing pitches, whereas the […] of sound waves is interpreted as loudness.
frequency; amplitude
The organ of corti sends electrical information about sound to the brain. The perceived pitch of a sound is determined by […].
the location of the activated hair cells on the basilar membrane
Transduction of sound stimuli occurs as a result of (3):
- bending of the hair cells, which stimulates the opening of the mechanically gated ion channels in their membrane
- receptor potential generation
- release of the neurotransmitter glutamate
The […] provides a reference point for the direction of bending of stereocilia on hair cells.
tallest stereocillium
What are the two types of deafness?
- conduction deafness
2. sensorineural deafness
Conduction deafness:
blocked sound conduction to fluids of internal ear
What are the causes of conduction deafness?
impacted earwax, perforated eardrum, otitis media, ostosclerosis of the ossicles
Sensorineural deafness:
damage to neural structures at any point from cochlear hair cells to auditory cortical cells
Sensorineural deafness is typically from…
gradual hair loss
Cochlear implants:
convert sound energy into electrical signals
Cochlear implants are drilled into […].
recess in temporal bone
