Special Senses Flashcards
What are the 5 special senses?
vision, hearing, taste, balance, smell
Why are the special senses defined as special senses?
Due to a specific central location with a specific receptor
What nerve aids in vision?
Optic Nerve (CN #2)
What nerve aids in smell?
olfactory nerve (CN#1)
What nerve aids in hearing?
Vestibulacochlear nerve (CN#8)
What is gustation?
taste
Which special senses are chemical, which are light, and which are stimulated due to mechanical stimulation?
Smell-chemical Taste-chemical Sight-light Hearing-mechanical stimulation Balance-mechanical stimulation
What type of neurons are olfactory neurons?
biopolar neurons
Where would you find olfactory epithelieum?
ethmoid bone (specifically the crib form palate)
Where would you find taste buds?
Lips, throat (pharynx), tongue, palate
What are the 5 basic taste sensations?
Salty, sour, sweet, bitter, Umami
What basic taste has the highest sensitivity?
Bitter, due to bodies reaction against ingesting posion
Smell is strongly influenced by?
Olfaction
The facial nerve innervates what part of the tongue?
anterior two-thirds
The Glossopharyngeal innervates what part of the tongue?
Posterior one third
The vagus nerve innervates the?
epiglottis
What do lacrimal glands produce?
tears
What does the lacrimal apparatus consist of?
lacrimal gland, lacrimal canaliculus, and nasolacrimal duct
Extrinsic eye muscles are made up of what?
six straplike muscles
Extrinsic eye muscles are what type of muscle?
Skeletal
What are the 6 extrinsic eye muscles?
Superior rectus Inferior rectus Medial Rectus Lateral Rectus Superior oblique Inferior obligue
What are the three layers of the eye?
Fibrous tunic, Vascular tunic, Sensory tunic
What are the names for the inner layer of the eye?
*hint: 5
Sensory tunic, Nervous Tunic, Nervous tunic, neural tunic, retina
Fiberous tunic has two layers, what are they?
Sclera-white part of the eye
Cornea-clear
Vascular tunic has 4 parts, what are they?
Choroid Ciliary body iris pupil retina
What are the ciliary body and ligaments responsible for?
changing the shape of the lens
What does the iris do?
regulates amount of light entering
What do dialators do?
enlarge the pupil
What do constrictors do?
shrink the pupil
Macula consists of mostly what type of photoreceptors?
cones
Fovea centralis has the highest amount of what?
What does this mean?
highest amount of cones, so they provide the highest visual acuity
What are cones responsible for?
color vision
What are rods responsible for?
Black and white vision
What is the purpose of the lens?
To focus light on retina
The anterior segment and anterior cavity contain what?
aqueous humour
The posterior segment and posterior cavity contain what?
Vitreous humour
Vitreous humor is produced when?
Before birth
Is the cornea vascular?
No
What is the visible axis (aka pathway through the eye)
******
cornea->anterior segment w/aqueous humor->pupil->lens->posterior segment w/vitreous humour->retina
What is emmetropia?
Normal sight
What is Myopia?
near sighted
What is hypertropia?
Far sighted
To see up close, the lens has to do what?
needs to curve (ball like)
To see at a distance the lens needs to do what?
Lens has to flatten
Rods consist of?
About 700 disks
What do the disks in rods contain?
rhodopsin and retinal
What does exposure to light activate?
rhodopsin
When rhodopsin is produced it makes what more sensitive?
the retina
What types of cones are there?
blue, red and green
The superior rectus muscle moves the eye?
upward
The inferior rectus moves the eye?
downward
The medial rectus moves the eye?
moves eye medially
The lateral rectus moves the eye?
laterally
The superior oblique moves the eye?
Downward and laterally
The inferior oblique moves the eye?
upward and laterally
What are the lateral canthus and the medial canthus?
corners of the eye where the eyelids attach
What is a caruncle?
“ball” in medial canthus
The tough outer layer, or ‘white’ of the eye is the?
sclera
The clear anterior part of the sclera is called?
the cornea
the choroid is what?
the vascular pigmented layer within the vascular tunic
What is the inner layer of the neural tunic that contains photoreceptors?
retina
What is the small pit where most cones are found?
fovea centralis
What is the region around the fovea centralis?
macula lutea
What is the point of attachment for optic nerves?
Optic disk
What is the region of the eye that contains no photoreceptors and is often referred to as the blind spot?
Optic disk
What does the ciliary body do?
causes tension on suspensory ligaments
What do suspensory ligaments do?
tension changes shape of lens
What does the lens do??
focuses light on retina
The anterior segment is located?
between the cornea and iris
the aqueous humor is?
water fluid in anterior segment
The posterior segment is located?
behind lens
The vitreous humor is?
What does it do?
A thick gel in posterior segment
Helps maintain and shape eye
What is an accommodation?
When curvature of lens changes for vision of near or distant objects
What is an astigmatism?
When lens is warped or not a perfect spherical shape
What are the three parts of the ear?
Outer ear, middle ear, inner ear
What are the parts of outer ear?
Auricle or pinna, External acoustic meatus, Tympanic Membrane
What are the parts of the middle ear?
Auditory ossicles (malleus, Incus, stapes), Eustachian tube
What is the function of the cochlear?
hearing
What is the function of the semi-circular canals?
Dynamic balance
What is the function of the vestibule?
Static balance
What stimulates the hair cell, which will create an action potential?
Bending the sterocilia
What are the three ducts of the cochlear?
vestibular duct, cochlear duct, tympanic duct
What is the anatomical name for the vestibular duct?
scala vestibuli
What is the anatomical name for the cochlear duct?
scala media
What is the anatomical name for the tympanic duct?
scala tympani
Where is the vestibular membrane located?
between the vestibular and cochlear ducts
Where is the basil membrane located?
between the cochlear and tympanic membranes
How do hair cells become stimulated?
Movement of sound waves shakes the tectorial membrane which bends the stereo cilia which creates an action potential that the brain interprets as sound
Higher pitched sounds are __________ to the oval window?
closer
Low pitch sounds are _____________ to the oval window?
Farther
In the Rhodopsin Cycle-
The first step is?
Retinal is attached inside the opsin to make rhodopsin
In the Rhodopsin Cycle-
The second step is?
Light activates rhodopsin by causing retinal to change shape, which causes opsin to change shape
In the Rhodopsin Cycle-
The third step is?
Activated rhodopsin time stimulates cell changes that result in vision
In the Rhodopsin Cycle-
The fourth step is?
Following rhodopsin from activation, retinal detaches from opsin
In the Rhodopsin Cycle-
The fifth step is?
Energy from ATP is required to bring retinal back to its original form
In the Rhodopsin Cycle-
The sixth step is?
Retinal attaches to opsin to form rhodopsin
What do the membranes of cones contain?
What does it contain?
Iodopsin, which contains retinal combined with opsin protein
How many does each eye have of rods and cones?
120 million rods
6/7 million cones
How many cones does the fovea centralis have?
approx. 35,000 cones
How do rods and cones differ in regards to synapsing with bipolar cells?
Several rods synapse with each bipolar cell
One cone cell synapses with one bipolar cell
What do horizontal cells synapse with?
Photoreceptor cells and bipolar cells
What do Amacrine cells synapse with?
biopolar and ganglion cells
What do interplexiform cells connect with and what do they do?
Horizontal & Amacrine cells forming feedback loops
What type of lens corrects myopia?
Concave lens
What type of lens corrects hyperopia?
convex lens
Name the visual axis?
Cornea->anterior seg. containing aqueous humor->pupil->lens->posterior segment w/vitreous humor->retina
What is binocular vision?
What is seen with two eyes at the same time
What in monocular vision?
What is seen with one eye
What is binocular vision responsible for?
depth perception
What are the parts of the external ear?
Outside the head to the tympanic membrane
What is the middle ear?
Air filled chamber medial to tympanic membrane
What is the inner ear?
Set of fluid filled chambers medial to the middle ear
External ear and middle ears are involved in what only?
Hearing
Inner ear has what two functions?
Hearing and balance
What is the external acoustic meatus lined with?
Hairs and ceruminous glands
What are the two small muscles in the middle ear that help dampen vibrations of the auditory ossicles caused by loud noises?
Tensor tympani-innervated by the trigeminal nerve
Stapedius-innvervated by the facial nerve
What is the chorda tympani?
Where does it cross in the ear?
Branch of the facial nerve carrying taste impulses from the anterior two thirds of tongue
Crosses through middle ear between malleus and incus
What are the two openings that provide air passages in middle ear?
One opens into the mastoid air cells in the mastoid process of temporal bone
Eustachian tube which opens into the pharynx
What is the name for the interconnecting, fluid filled tunnels, and chambers within the temporal bone?
Bony labyrinth
What is the bony labyrinth lined with?
endosteum
What is the name for the similarly shaped but smaller set of membranous tunnels
Membranous labyrinth
What is the membranous labyrinth filled with?
Endolymph
What is the bony labyrinth filled with?
perilymph
What are spiral lamina?
the bony core of the cochlea that is shaped like a screw with threads
What is the helicotrema?
The opening connecting the two chambers, the scala tympani and the scala vestibuli
What is a hair bundle?
the conical group of the stereo cilia from one inner hair cell
What connects the tip of each stereo cilium in a hair bundle to the side of a longer stereocilium
a tip link
Amplitude is what?
volume
Lower amplitude means what?
Are the sound waves tall or short
lower volume
short
Higher amplitude means what?
Are the sound waves tall or short?
higher volume
Tall
What is Timbre?
resonance quality of sound or overtones of sound
What is frequency?
Pitch
What does a lower frequency mean?
Are the sound waves closer or farther apart?
Lower pitch
Farther apart
What does higher frequency mean?
Are the sound waves closer or farther apart?
higher pitch
Closer together
What is the sound attenuation reflex?
When loud sounds cause muscles (tensor tympani and stapidus) to contract and dampen movement of auditory ossicles
Axons of the sensory neurons supplying hair cells for what?
cochlear nerve
Where do neurons from cochlear ganglion synapse with the CNS?
Cochlear nucleus in the medulla oblongata
What type of balance is associated with the vestibule and is involved with the position of the head relative to gravity?
static balance
What type of balance is associated with the semi-circular canals and involved in changes in the direction and rate of head movements?
Dynamic balance
What parts of the vestibule is static balance associated with?
the utricle and the saccule
What is the specialized patch of epithelium located in both utricle and saccule?
Macula
What are otoliths?
crystals of calcium carbonate and protein located within the otolithic membrane
What is located under the otolithic membrane?
hair cells
What is the special sensory epithelium within the ampulla of the semi-circular canal?
crista ampullaris
Semicircular canals detect changes in the rate of movement rather than the movement alone because of what?
Displacement of the cupula is most intense when the rate of head movement changes rapidly
Axons of the sensory neurons supplying the hair cells of the maculae and crista ampullaris form what?
The vestibular ganglion
What is age-related hearing loss?
presbyacusis
With age the the number of hair cells in the
__________, __________, &_________ decreases?
Also, the number of ____________ declines?
Sacule, utricle, and ampulle
otoliths
Which cells have no axons but release neurotransmitters when stimulated?
Last cells
What do tears contain?
water, salts, mucus and lysozyme
Aqeuous humor exits the eye via?
scleral venous sinus
Contraction of the smooth muscle in the ciliary body causes what?
Lens to become more spherical and pupils to constrict
Looking at an object 30 ft away and suddenly looking at an object 1 ft away what will occur?
Medial rectus contracts,
pupils constrict
Lens of the eye becomes more spherical
where do axons in the optic nerve from right eye go?
Some go to right occipital lobe and some go to left occipital lobe
The spiral organ is found within the?
cochlear duct
An increase in the loudness of sound occurs as a result of an increase in the __________ of the sound wave
amplitude
Waves coming from the outside encounter what in what order?
1) Perilymph
2) vestibular membrane
3) endolymph
4) basilar membrane
Damage to the semicircular canals affects the ability to detect?
Movement of the head in all directions
