A&P 1: Special Senses Flashcards
1
Q
What are the two classes of sensory modalities?
A
General senses
Special senses
2
Q
General senses include what two senses?
A
Somatic Senses
Visceral Senses
3
Q
What is the first step in the process of sensation?
A
Activation of sensory receptors by stimulus
4
Q
Sensory receptors comprise either _____ or _____
A
Specialized cells
Dendrites of sensory neuron
5
Q
4 events required for sensation
A
Stimulation
Transduction
Generation
Integration
6
Q
For stimulation of the sensory receptor to occur, the stimulus must occur within _______?
A
Receptive field of the receptor
Body region where stimulation causes a response
7
Q
Sensory receptors transduces energy in a stimulus into a _______
A
Graded potential
8
Q
Sensory receptors can be placed into 3 classifications
A
Microscopic appearance
Origin of stimuli
Type of stimulus
9
Q
3 classifications by microscopic appearance
A
Free nerve endings
Encapsulated nerve endings
Separated cells
10
Q
Define Free Nerve Endings
A
Bare dendrites with no structural specialization
11
Q
Define Encapsulated Nerve Endings
A
Dendrites enclosed in connective tissue capsule
12
Q
Define Separate Cells
A
Specialized cells that synapse with first order sensory neurons
13
Q
What do separate cells detect?
A
Hearing/equilibrium hair cells
Photo receptors
Gustatory receptors
14
Q
Sensory receptors produce what two types of graded potentials?
A
Generator potential
Receptor potential
15
Q
What produces Generator Potentials?
A
Free Nerve endings
Encapsulated nerve endings
Receptive part of olfactory receptors
16
Q
A cold-sensitive receptor is an example of what type of sensory receptor?
A
Free Nerve Ending
17
Q
Lamellated corpuscle is an example of what type of sensory receptor?
A
Encapsulated nerve ending
18
Q
Of the two types of graded potentials made by sensory receptors, which one is not a first-order neuron?
A
Receptor potential
19
Q
Define Adaptation
A
Decrease in generator/receptor potential amplitude to a prolonged stimulus
20
Q
3 examples of rapidly adapting receptors
A
Touch
Pressure
Smell
21
Q
3 examples of slow adapting receptors?
A
Pain
Proprioception
Chemical
22
Q
Define somatic sensations
A
Arise from stimulation of sensory receptors in skin/subcutaneous layer in mucus membrane, muscles, tendons, joints and inner ear
23
Q
Define Cutaneous sensations
A
Somatic sensations that arise from stimulating surface of skin
24
Q
Free nerve endings of tactile sensations sense what stimuli?
Encapsulated sense what?
A
Itch and tickle
Touch, pressure, vibration
25
Define Touch Sensation
Stimulation of tactile receptors in skin or subcutaneous layer
26
What are the 2 types of touch?
Crude- Something is contacting but can't determine location, shape, size and texture
Fine- specific information is provided, location, shape, size, texture
27
Define Pressure
Sustained sensation that is felt over larger area than touch due to deformation of deeper tissues
28
Define Vibration
Rapid and repetitive sensory signals from tactile receptors
29
What are the 2 types of receptors for vibration?
Meissner corpuslces- low-frequency vibrations
Pacinian corpuscles- higher frequency vibrations
30
Define itch
Stimulation of free nerve endings by certain chemiclas, possible local inflammatory response
31
Define tickle
Sensations arising from free nerve endings and lamellated corpuscles
32
Thermoreceptors are unspecialized free nerve endings that respond to changes primarily within the ____ range
Innocuous
33
Where are thermal sensation receptors?
Skin
Cornea
Tongue
Bladder
34
Pain receptors are found in every tissue in the body except?
Brain
35
Tissue irritation/injury release what 3 chemicals that stimulate nociceptors?
Kinins
Prostaglandins
K+ ions
36
Define Kinins
Polypeptides that cause vasodilation, increase vessel permeability, and chemotactic agents for phagocytes
37
Define Prostaglandins
Lipids that intensify effects of histamine, kinin and stimulate emigration of phagocytes through capillary walls
38
Types of pain are differentiated based on?
Types of nerve fibers that propagate impulses
| Where in the body the type of pain can occur
39
Fast pain fibers are AKA?
Acute
Sharp
Pricking
40
Pain by location of receptors can be divided into 3 types
Superficial
Deep
Visceral
41
When does referred pain usually occur?
Nerve fibers from HIGH sensory input and fibers from LOW input converge on same levels of the spinal cord
42
What are the 3 types of proprioceptors
Muscle spindles
Tendon organs
Joint kinesthetic receptors
43
Define Muscle spindles
Proprioceptors in skeletal muscles that participate in stretch reflexes
44
Define Tendon Organs
Located at junction of tendon and muscle, provide info about changes in muscle force
45
What is the purpose of Tendon Organs?
Protect tendons and muscles from damage from tension
46
Define Joint Kinesthetic Receptor
Provide info about parameters associated with movement of synovial joints
47
What are the parameters of joint kinesthetic receptors?
Pressure
Velocity changes
Tension
48
Where are joint kinesthetic receptors located?
Around articular capsule of synovial joint
49
Olfaction produces a ____
| Gustation produces a _____
```
O= generator potential
G= receptor potential
```
50
Olfactory epithelium consists of what 3 kinds of cells?
Olfactory receptors
Supporting cells
Basal stem cells
51
Olfactory supporting cells are AKA ?
Sustentacular cells
52
Olfactory receptors are what kind of neurons?
Bipolar first-order neurons
53
Each olfactory receptor has what 3 parts?
Axon ending in olfactory bulb
Knob shaped dendrite
Cilia projecting from dendrite
54
What are the olfactory hairs?
Cilia projecting from dendrites of olfactory receptors
55
What is the site of olfactory transduction?
Olfactory hairs
56
How are olfactory responses initiated?
Chemical stimulation of odorant molecule that produces a generator potential
57
What are the olfactory supporting cells?
Columnar cells of mucous membrane lining the nose
58
Supporting cells in the nose provide what 3 things?
Physical support
Nourishment
Electrical insulation
59
What is unique about the basal stem cells?
Undergo continuous division producing new olfactory receptors since they only life for a month
60
What are Olfactory Glands
| What are they AKA?
Produce mucus
| Bowman's glands
61
What is the function of the Olfactory Glands?
Moisten epithelium
| Dissolve ordorants
62
What CN innervates supporting cells and olfactory glands?
CN7
63
Where do olfactory nerves terminate?
Olfactory bulbs- paired gray matter masses
| Site of end of first order and synapse with second order neurons
64
What is formed when olfactory bulb axons extend posteriorly?
Olfactory tract
65
Where is the primary olfactory area?
Lateral olfactory area
| Site of conscious smell beginning
66
What is unique about the olfactory pathway?
Only sensation that reaches cerebral cortex without synapsing with thalamus first
67
How do olfactory senses trigger emotion/memory linked responses to odors?
Olfactory tract projects to limbic system and hypothalamus
68
Where do second order olfactory neurons project to?
Olfactory bulb to brain to form a sensory map
69
What kind of deficiency is the cause of many cases of anosmia?
Zinc- growth factor for receptors of chemical senses
70
Taste buds are located in what 4 areas?
Tongue
Soft palate
Pharynx
Epiglottis
71
Taste buds consist of what 3 types of cells?
Gustatory receptor cell
Supporting cell
Basal cell
72
Where is a taste pore?
Apex of taste bud
73
Define gustatory hair
Long, single microvillus projecting through taste pore
74
What is the sequence of cellu progression for gustatory cells?
Basal->supporting->gustatory
| Gustatory live for 10 days
75
What is the site of taste transduction?
Gustatory hairs
76
Sweet tastes are associated with what?
| Why?
Safe food
| Requirement for carbs
77
What is the conventional receptor location for sweets?
Tip of tongue
78
Sour tastes are associated with what?
Spoiled foods
79
What is the conventional receptor location of sours?
Back sides of tongue
80
Bitter tastes are associated with what?
Poisonous foods
81
Where is the conventional receptor location of bitters?
Back middle of tongue
82
Salty tastes are associated with what?
Sodium Chloride
83
Where is the conventional receptor location of salty?
Sides of tongue
84
Umami is the taste of what?
Amino acids
| Meaty, savory, broth like
85
Taste buds occur in elevations of the tongue called what?
Papillae
86
What are the 3 types of papillae?
Vallate
Fungiform
Foliate- lost during childhood
87
Define filiform papillae
Papillae with tactile receptors to distinguish food textures but can't taste
88
What taste has the lowest threshold?
Bitter
| Sour slightly higher
89
Define flavor
Combination of taste plus odor (retronasal olfaction)
90
Define retronasal olfaction
Volatile food chemicals carried into nasal cavity from behind
91
Olfactory epithelium can act in what two types of olfaction?
Retronasal
| Orthonasal
92
What sense pathway doesn't have an axon?
| What are they called instead?
Gustatory
| Graded potential produced called receptor potentials
93
What 3 CNs make up the gustatory pathway?
CN 7- anterior 2/3 of tongue
CN 9- posterior 1/3 of tongue
CN 10- throat and epiglottis
94
Where is the gustatory nucleus?
Medulla obonglata
95
Where do gustatory axons project to from the medulla?
Limbic
Hypothalamus
Thalamus
96
Where is the primary gustatory area?
Parietal lobe of cerebral cortex to give conscious perception of taste
97
3 functions of palpebrae
Protect from light
Protect from objects
Spread lubrication
98
Define palpebral fissue
Space between upper and lower eyelids
99
Define Commissures
Angles of the palpebral fissure
100
Define lacrimal caruncle
Medial commissure containing sebaceous and sudoriferous glands
101
What are the structures of the eyelid from superficial to deep?
```
Epidermis
Dermis
Subcutaneous tissue
Fibers of orbicularis oculi muscle
Tarsal plate
Tarsal glands
Conjunctiva
```
102
Define Tarsal Plate
Fold of CT that gives form and support to eyelids
103
Define Tarsal Glands
Secretes fluid to keep eyelids from adhering to each other
104
Tarsal glands are AKA ?
Meibomian glands
105
Define Palpebral conjunctiva
| Define Bulbar conjunctiva
```
P= lines inner aspect of eyelid
B= on anterior surface of eyeball, covers sclera but not cornea
```
106
Define lacrimal apparatus
Group of structures that produce and drain tears
107
What are the 3 parts of lacrimal fluid
Salts
Mucus
Lysozyme
108
How is lacrimal fluid drained into the eye?
Excretory lacrimal duct on surface of conjunctiva of upper lid to pass medially over eye ball
109
What CN innervate the extrinsic eye muscles?
CN 3 4 6
110
Define cardinal directions of gaze?
6 of the 8 eye movements that are associated with a single extrinsic muscle
111
Define Strabismus
Imbalance of extrinsic eye muscles so lines of vision are not parallel
Deviant eye input disregarded and becomes functionally blind
112
What is the layman term for Strabisus?
Lazy eye
113
Define Nystagmus
Rapid involuntary movement of eyeballs
| Sign, not a disease
114
What type of nystagmus is more frequent?
Horizontal
115
Define Vestibular Nystagmus
Eye movements that occur during/after rotational motion
116
What is horizontal gaze nystagmus useful?
Police use it to test field sobriety
117
What are the 3 layers of the eye?
Fibrous tunic
Vascular tunic
Retina
118
Define Fibrous Tunic
| What are it's two parts?
Superficial coat of eye that is avascular
| Cornea and Sclera
119
Define Cornea
Transparent coat that covers iris
| Curved so it can focus light
120
Sclera covers entire eye except for where?
Cornea
121
What is the function of the sclera?
Eye shape/rigidity
122
Define Vascular Tunic
| What are the 3 parts?
Middle layer of eye
| Choroid, ciliary body, iris
123
What are the functions of the choroid?
Vascularized to provide nutrients to posterior surface of sclera
124
What are the two parts of the Ciliary body?
Ciliary process
| Ciliary muscle
125
Define Ciliary processes
Contain blood capillaries that secrete aqueous humor
126
Define Ciliary Muscle
Alters shape of lens
127
When the lens more spherical, what type of vision is allowed?
Contracted Ciliary, reduced tension of suspensory ligaments, more spherical shape for closer vision
128
Where does the iris connect to the eye?
Ciliary processes
129
What does the Parasympathetic and Sympathetic systems alter in the eye?
Parasymp- sphincter pupillae (circular muscle) to decrease pupil size
Symp- dilator pupillae (radial muscle) increases puil size
130
What is the inner coat of the eye?
Retina
131
What does the retina mark the beginning of?
Visual pathway
132
What is the only place in the body where blood vessels can be directly viewed and examined?
Retina
133
What is the optic disc?
Site where optic nerve exits eyeball
134
What two structures are adjacent to the optic disc?
Central retinal artery
| Central retinal vein
135
What is the function of pigmented layer of the eye?
Absorbs stray light to prevent reflection/scattering
136
What is the neural layer of the retina?
Outgrowth of brain
137
What are the 3 layers of the neural layer?
Photoreceptor
Bipolar
Ganglion
138
What are the 2 zones of the neural layer?
Outter/inner synaptic layer
139
What are the two types of photoreceptors found in the neural layer?
Rods- low threshold, only see shades of gray
| Cone- higher threshold, color vision
140
Define Macula Lutea
Exact center of visual axis of eye in posterior retina
141
What is the small depression in the center of the macula lutea and what does it contain?
Central fovea, only cones
142
What part of the eye has the highest visual acuity/resolution?
Fovea centralis
143
What is the blind spot of the eye?
Optic disc, no rods or cones
144
What does age-related macular disease effect in the eye?
Degeneration of retina and pigmented layer within macula lutea
145
What kind of vision do age related macular disease PTs have?
Retain peripheral
| Lose straight ahead sight
146
What are the two types of age-related macular degeneration?
Dry- central layer fades due to pigmented layer atrophy/degeneration, no treatment
Wet- new blood vessels form and leak plasma/blood under retina, treated with laser surgery
147
Where is the lens located?
Behind pupil and iris
148
What are the proteins of the lens called?
Crystallins
149
What is the variably refractive medium of the eye?
Lens
150
Define cataract
Loss of lens transparency
151
How are cataracts repaired?
Removal of lens and implantation of new artificial lens
152
What divides the eye into its two cavities?
Lens
153
What are the two chambers of the anterior chamber?
Anterior- between cornea and iris
| Posterior- behind iris, front of lens
154
What type of liquid is in the chambers of the anterior cavity?
Aqueous humor
155
Which fluid makes up the majority of intraocular pressure?
Aqueous humor
156
How is aqueous humor made?
Filtration of blood by capillaries of ciliary processes
157
Where does aqueous humor flow within the eye?
Between iris and lens, through pupil, into anterior chamber, drains to scleral venous sinus at junction of sclera and cornea, returns to blood
158
How often is aqueous humor replaced?
90 min
159
What is the Scleral venous sinus AKA?
Canal of Schlemm
160
Define Glaucoma
High intraocular pressure
161
What type of damage does glaucoma cause on the eye?
Optic nerve and retina damage leading to blindness
162
What causes glaucoma?
Impaired drainage of aqueous humor
163
Define the ocular angle
Canal of Schlemm at vertex of the angle formed by intersection of cornea and iris
164
What are the two types of glaucoma?
Closed- posterior chamber pushes iris forward, closing ocular angle, prevents drainage of aqueous humor
Open- abnormality of trabecular meshwork of Schlemm cana impede outflow of aqueous humor
165
How is glaucoma treated?
Cholinergic agonists- constrict pupil, contract ciliary muscles, decreases pressure
166
How does glaucoma treatment work in closed or open angle glaucoma?
Closed- pupil constriction lowers intraocular pressure by pulling iris away from Schlemm to open angle
Open- ciliary muscle contraction stretches trabecular meshwork to open tubules
167
What is the larger chamber of the eye?
Vitreous chamber
168
What part of the eye holds retina against choroid?
Vitreous body
169
What part of the eye is phagocytic and provides unobstructed vision?
Vitreous body
170
What are the 3 parts of the vitreous body jelly?
Water
Hyaluronic acid
Collagen
171
Where does the vitreous body attach to the retina?
| What is this junction important?
Behind ora serrata at the optic disc
| Retinal tears/detachment
172
Define Ora Serrata
| What does it mark?
Junction between retina and ciliary body
| Transition from non-photosensitive area of retina to photosensitive region
173
Where does the vitreous body attach to the Ora Serrata?
Anteriorly behind ora serrata
174
Define blepharitis
Inflammation of eyelid
175
Diabetic retinopathy is degeneration from what type of diabetes?
Diabetes mellitus
176
Define Exotropia
Outward turning of eyes
177
Define Keratitis
Inflammation/infection of cornea
178
Define miosis
Constriction of pupil
179
Define Mydriasis
Dilation of pupil
180
Define Ptosis
Falling/dropping eye lid
181
Define Scotoma
Reduced/lost vision in visual field
182
Define Tonomieter
Measures intraocular pressure
183
Define Trachoma
Serious form of conunctivitis
| Greatest single cause of blindness
184
Define refraction
Light passing through transparent substance and passes into second transparent substance with a different density
185
What causes refraction?
Light hitting and bending at different times and being refracted
186
What type of lens causes convergence?
| What type of lens causes divergence?
Convex
| Concave
187
How are images received on the retina?
Upside down
| Left to right reversal
188
Light rays reflect from objects are seen as parallel if they are at least ___ ft from the viewer
Why is this?
20ft
| Ciliary muscle is relaxed, lens if flat
189
What happen if light rays are received from objects closer than 20ft?
Not parallel
| Lens must be thicker to focus
190
Define accommodation
Ciliary muscle contracts, reduces tension on ligaments, lens becomes more spherical
Increased curvature for near vision
191
Without tension from suspensory ligaments, lens assumes what shape?
Convex
192
What happens to make the lens less convex?
Ciliary muscles relax
| Choroid is spring like pulls lens through ligaments
193
How does the lens become thicker?
Ciliary muscle contracts
| Choroid stretched, releasing tension on lens
194
Define Near Point of Vision
Minimum distance from eye that an object can be clearly focused
195
Define Presbyopia
Loss of elasticity of the lens due to age
People need glasses
Glasses need bifocals
196
A normal eye is termed as _____
Emmetropic
197
What are 3 refraction abnormalities?
Myopia- nearsightedness
Hyperopia- farsightedness
Astigmaism- irregular cornea curvature
198
What causes myopia?
Eye is too long relative for focusing power of the cornea/lens
199
What type of image is formed with myopia?
| How is this corrected?
In front of retina due to eleongated eye/thick lens
| Concave lens
200
How does hyperopia occur?
Eye is too short relative to focusing power of cornea/lens
201
What type of image is produced with hyperopia?
| How is it corrected?
Focused behind retina due to shoretened eye/thin lens
| Convex lens
202
What causes Astigmatism
Irregular curvature of cornea/lens
203
What type of image is produces with astigmatism?
| How is this corrected?
Blurred/distorted/out of focus
| Lens that rotate axis of lens
204
Define binocular vision
| What does this provide?
Both eyes focus on only one set of objects
| Depth and 3D
205
How does binocular vision occur?
Light rays from object stike corresponding points of two retinas and each eye sees same image from different angles
206
Define stereoscopic vision
Brain fusing binocular vision input into two different images from each eye
"seeing solid"
207
Define Convergence
Medial movement of eyes so both are toward object being viewed
208
Where are cones more numerous?
| Where are rods more numerous?
```
Cones= central fovea
Rods= ring around foveal pit
```
209
What is the cone peak?
Central fovea, area with the most cones
210
What part of the rod/cone is the area that light energy is transduced?
Outer segment
211
What does the outer segment of the cone look like?
| What does the tip of each rod look like?
Cone- folds, pleated fabric
| Rods= stacked discs
212
When does rod and cone phagocytosis occur?
Rod- exposed to light
| Cone- darkness
213
What are the 3 structures contained within the inner segment of rods and cones?
Nucleus
Golgi app.
Mitochondria
214
What end of the rod or cone expands in the synaptic terminal?
Proximal
215
Define photopigments
Colored, integral proteins in membrane of outer segment of rods/cones that undergo structural changes when light is absorbed
216
What are the two parts of photopigments?
Retinal- derived from Vit A
| Opsin- glycoprotein
217
What is the photopigment in rods?
| What does it absorb?
Rhodopsin
| Blue and green
218
What aer the 3 photopigments in cones?
Photopsin I- yellow
Photopsin II- green
Photopsin III- blue-violet
219
What portion of photopigment is different in each of the different photopigments?
Opsin portion
220
What part of the photopigment is key in transducing light?
Retinal
221
What happens to retinal in darkness?
Cis-retinal
222
What happens when cis-retinal abosrobs light photons?
Trans-retinal
223
Define isomerization
Cis to trans conversion
224
Define regeneration
Light-induced insomerization of cis-trans causing rhodopsin to decompose
Photopigments need to be re-made
Cis-retinal can rebind to opsin forming functional photopigment
225
What is the normal color of rhodpsin?
Red
226
Define Bleaching of Photopigment
Presence of light causes cis-retinal converted to trans-retinal
Opsin is without retinal is colorless
227
What enzyme isomerases trans to cis retinal?
Retinal isomerase
228
What is causing the painful bright light when someone goes from dark to light?
Photopigments being broken down
229
Define nyctalopia
| What causes it
Inability to see well in low light levels
| Low Vit A
230
How many rods synapse with a bipolar cell?
| How many rods synapse with a bipolar cell?
Rod- 6-600
| Cone- 1
231
Convergence of many rods into a single biopolar cells causes _____ light sensitivity and a _____ in image acuity
Increase
| Decrease
232
Cone vision is ____ sensitive and ____ acuity
Less
| Higher
233
When does the optic nerve stop and the optic tract begin?
Passage through optic chiasm
234
Where does the otpic tract terminate?
Lateral geniculate nucleus of thalamus
235
Thalamus forms optic radiation and projects them to where?
Primary visual area in occipital lobes of cerebral cortex
236
What is the visual field?
| What is the field of binocular vision?
VF- everything seen by that eye
| FoB- where two visual fields overlap
237
Visual field of each eye is divided into what two regions?
Nasal (central half)
| Temporal (peripheral half)
238
How is light received from each part of the visual field?
Nasal half light fall on temporal half of retina
| Light from temporal half fall on nasal half of retina
239
Which optic field does not cross over to the opposite half of the brain?
Temporal
240
What part of the eye govern constriction of pupils and coordinate head and eye movements?
Axon collaterals of retinal ganglion
241
How is circadian rhythms formed?
Collaterals go to suprachiasmatic nucleus of hypothalamus
242
Define Optic Radiations
Projections of axons from thalamus to primary visual area of cortex on the same side
243
Define Amblyopia
Loss of visual in a normal eye caused by no/poor transmission of visual stimuli to optic nerve and brain
"Lazy Brain"
244
3 systems within the cerebral cortex process and interpret visual signals based on what 3 input?
Shape
Color
Movement/location/spatial
245
What are the 3 regions of the ear?
External- collects and funnels sounds
Middle- conveys vibrations to oval window
Internal- receptors for hearing and equilibrium
246
What are the 3 parts of the external ear?
Auricle
External auditory canal
Eardrum
247
What is the helix of the ear?
| What is the inferior portion called?
Outer rim
| Lobule
248
Define Tragus?
| What structure is opposite to it?
Pointed eminence projecting back over meatus
| Antitragus
249
What structures are near the region of the outer ear?
Mastoid process posterior to lobule
| Superficial temporal artery anterior to tragus
250
How/where does the incus articulate?
Laterally w/ malleus
| Medially w/ stapes
251
Which ossicles produce bulges on the TM and can be viewed?
Handle/lateral process of malleus
| Long limb of incus
252
What are the 2 skeletal muscles that attach to ossicles?
Tensor tympani muscle
| Stapedius muscle
253
Where does the Tensor Tympani originate and insert with what CN?
Wall of auditory tube
Inserts on handle of malleus
CN5
254
What is the function of the Tensor Tympani muscle
Limits movement
| Increases tension on eardrum to prevent damage from loud noises
255
Where does the Stapedius muscle origninate, insert and get innervated by?
Poasterior wall of ear cavity
Stapes
CN7
256
What is the function of the Stapedius muscle?
Dampens large vibrations of stapes due to lout noises
257
What is the smallest skeletal muscle in the huan body?
Stapedius muscle
258
What is the visual appearance of a normal TM?
Pearly gray and translucent
259
What is the cone of light?
| What is it AKA?
Reflection of otoscope illuminator
| Light reflex- radiates anterioinferiorly in healthy ear
260
The Eustacian Tube is AKA?
Auditory Tube
| Pharyngotympanic tube
261
What does the Eustacian tube connect?
Middle Ear with Nasopharynx
262
What 2 events opens the eustacian tube?
Yawn
| Swallow
263
Opening the eustacian tube allows pressure to equalize where and prevents what?
Middle ear and atmosphere
| Pain and vertigo
264
Inner ear is AKA ? with waht 2 divisions
Labyrinth
| Bony and Membranous
265
What are the 3 areas of the bony labyrinth?
Semicircular canas
Vestibule
Cochlea
266
What/where is the membranous labyrinth?
Sacs and tubes in the bony labirynth
267
Define Perilymph and its location
Similar to CSF surrounding membranous labyrinth
268
Where is Endolyph found?
| What does it have a high level of?
Membranous lbyrinth
| K+
269
Define Vestibule
Oval center of bony labirynth and part of membranous in the center
270
What two structures make the vestibule?
Utricle
| Saccule
271
Where is the oval window?
Vestibule
| AKA Vestibular window
272
What appearance do the semicircular canals have?
Right angles to each other
Anterior/Posterior- vertical orientation
Lateral- horizontal
273
What structure is at the end of each semicircular canal?
AMpulla
274
Parts of the membranous labyrinth are in the semicircular canals and are called ? and connect to ?
Semicircular ducts
| Connect to urticle
275
Define Menieres Disease
Increased endolymph
Fluctuating hearing loss
Tinnitus
Whirling vertigo
276
The vestibular branch of CN8 is made of what 3 nerves?
Ultricular
Saccular
Ampullary
277
Where are CN8 sensory neuron cell bodies located?
| Where are the motor neurons located?
Vestibular ganglia
| Pons- project to semicircular, saccule and utricle
278
What is the center of the chochlea called?
Modiolus
279
Cochles has a Y-shaped partition that forms what 3 channels?
S. Media- AKA cohclear duct
S. Vestibuli- ends @ oval window
S. Tympani- ends @ round window
280
S. Vestibuli and S. Tympani are both filled with what fluid?
Perilymph
281
S. Vestibuli and S. Tympani are separated except for where?
Helicotrema
| "hole in the spiral"
282
Scala media is a continuation of ?
Membranous Labyrinth
283
What two membranes contain perilymph within the respective scalae?
Vestibular Mem- S. Vestibuli
| Basilar Mem- S. Tympani
284
Spiral organ/Organ of Corti is on what membrane?
Basilar within cochlear duct
285
Where are the hair cells that are the receptors for hearing located?
Cochlea
286
Hair cells in the spiral organ are in what 2 groups?
Inner- single row
| Outer- three rows
287
What do the inner and outer hair cells synpase with?
1st order sensory neurons
| Motor neurons from Cochlear Branch of CN8
288
Where/what are the only neurons that have a myelin sheath surround the cell body?
Afferent fibers from cochlea
289
Cell bodies of sensory neurons are located in the ____
| Cell bodies of motor neurons are located in the _____
Spiral ganglion
| Pons
290
Which membrane projects over and contact the cochlea hair cells?
Tectorial
291
Define sound
Alternating High and Low pressure regions of a medium
292
```
Frequency = _____
Amplitude = _____
```
Pitch
| Volume= intensity
293
Sound is _____ vibrations
sympathetic
294
What is the most acute and audible frequency ranges?
```
Acute= 500-5000 Herts/cps
Audi= 20-20K Hz
```
295
Amplitude threshold is defined as ?
0 dB at 1000 Hz
| When healthy ear can detect sound from silence
296
Normal conversation = _dB
OSHA hearing req @ __dB
Rock concert = _dB
60
90
110
297
How are shorter sterocilia connected to taller sterocillia?
Tip link protein
298
What kind of ion channel is associated with tip link proteins?
Mechanically gated ion channel
299
Steps of hearing
Sterocilia bend towards taller hair
Transduction channels open
Cations enter enolymph and depolarize
Opposite bending closes channel
300
Axons of the cochlear branch synapse with which neurons?
Cochlear nuclei in medulla oblongata
301
Neurons that dcussate in medulla and ascend to where?
Lateral lemniscus on opposite side to terminate in inferior colliculus of the midbrain
302
Axons from the cochlear nuclei that don't go to the medulla end where?
Superior olivary nucleus in pons
303
How can we tell the direction of sounds?
Difference in timing of impulses arriving to superior olivary nuclei
304
Where are impulses sent to after the inferior colliculus?
Medial geniculate nucleus of the thalamus
Then
Primary auditory area of cerebral cortex
305
Exceptionally loud noises damages what part of the hearing sequence?
Sterocilia
306
What are the two types of deafness?
Sensorineural- damage/disease of pathway of CN8
Conduction- impaired mechanisms of external/middle ear
307
Define Otoacoustic Emissions and their usefulness
Sounds produced by cochlea and are used to test infants for deafness
308
What are the two types of equilibrium
Static- position against gravity
| Dynamic- position against sudden movement
309
What are the receptor organs for equilibrium?
Vestibular apparatus- includes saccule, utricle and semicircular ducts
310
Where/what is the macula
Walls of utricle and saccule
Horizontal to utricle
Vertical to saccule
311
Maculae is made up of what 2 kinds of cells?
Hair- sensory receptors
| Supporting- form otolithic membrane
312
What are the two types of hairs that are in a bundle?
Sterocilia- actually microvilli
| Kinocilium- one per bundle, true cilium, longer than longest sterocilia of the bundle
313
What covers the surface of the otolithic membrane?
Otoliths- calcium carbonate crystals
314
What causes the otolithic membrane to slide over hair cells?
Head tilts or Acceleration that causes inertia
315
Maculate respond only to what two types of changes?
Acceleration or Velocity of the head
316
3 parts that make up Dynamic Equilibrium
3 semicircular ducts
Saccule
Utricle
317
What is located in the ampullas that are found at the end of each semicircular canal?
Crista Ampullaris
318
Each Crista Ampullaris contains what 3 things?
Hair cells
Supporting cells
Cupula- gelatinous material
319
Define Vestibular Nystagmus
Strange eye movements that occur after rotational movements
320
Equilibrium cell bodies are located where?
Vestibular ganglia
321
Equilibrium pathway axons comprise what?
Vestibular part of CN8
322
Most axons of vestibular branch synapse where?
Vestibular nuclei in medulla oblongata
323
What happens to the equilibrium axons that dont synapse in the medulla?
Enter cerebellum through inferior cerebellar peduncles
324
How are the cerebellum and vestibular nuclei connected?
Bidirectional pathways
325
Define Cochlear Implant
Device that translates sounds into electrical signals for brain interpretation
326
Define Presbycusis
Age related loss of hearing
327
Define Otalgia
Earache
328
Define Sensorineural deafness
Impairment of hair cells in cochlea or damage to cochlear branch of CN8
329
Define Conduction Deafness
Deafness caused by impairment of external/middle ear mechanisms ability to transmit to cochlea
330
Define Ottitis Media
Middle ear infection
331
Define Tympanotomy
Tube placed into eardrum to drain fluid from middle ear
332
Define Barotrauma
Damage/pain from pressure changes, usually affecting the middle ear
333
Define Vertigo
Sensation of spinning, either world or person
