HEENT Anatomy Flashcards
(240 cards)
1
Q
The Special Senses Include?
A
Smell, Taste, Vision, Hearing, and Balance
2
Q
The General Senses include?
A
Somatic Senses
Visceral Senses
3
Q
Somatic Senses include?
A
- Tactile Sensations (Touch, Pressure, and Vibration.
- Thermal Sensations (Warm and Cold)
- Pain Sensation
- Proprioceptive sensations (Joint and Muscle Position sense and movements of the limbs and head)
4
Q
Visceral Senses provide?
A
Information about conditions within internal organs
5
Q
The Conscious or subconscious awareness of change in the external or internal environment is?
A
Sensation
6
Q
Four conditions for Sensation to occur?
A
- Stimulus
- Sensory Receptor
- Conduction of nerve impulses
- Integration from the Brain
7
Q
What is a Stimulus?
A
A change in the environment, capable of activating certain sensory neurons.
- Ex: Light, heat, pressure, mechanical energy, or chemical energy
8
Q
What is the job of a Sensory Receptor during a Sensation?
A
Must convert the stimulus to an electrical signal which ultimately produces one or more nerve impulses if it large enough.
9
Q
How does Conduction work during a Sensation?
A
Nerve impulses must be conducted along a neural pathway from the sensory receptor to the brain.
10
Q
How does Integration play a role during a Sensation?
A
A region of the brain must receive and integrate the nerve impulses into a sensation.
11
Q
What characteristic do most sensory receptors share?
A
Adaptation
12
Q
Adaptation is?
A
A decrease in strength of a sensation during a prolonged stimulus
13
Q
What is an important result of Adaptation?
A
the perception of a sensation may fade or disappear even though the stimulus persists.
Ex: first stepping in to a hot shower, and over time the sensation becomes more comfortable.
14
Q
Which types sensations where receptors Adapt rapidly?
A
Pressure, Touch, and Smell
15
Q
Which types of sensations receptors Adapt slowly?
A
- Pain
- Body Position
- Chemical Composition of the Blood
16
Q
How are Sensory Receptors grouped into different classes?
A
Structure and Function
17
Q
Structural Groups of Receptors
A
Free nerve endings
Encapsulated Nerve Endings
Separate Cells
18
Q
Free Nerve Endings
A
Bare dendrites associated with pain, tickle, itch, some touch sensation
19
Q
Receptors for pain, temperature, tickle, itch and some touch sensations are?
A
Free nerve endings
20
Q
Dendrites enclosed in a connective tissue capsule for pressure, vibration, touch.
A
Encapsulated Nerve Endings
21
Q
Which receptors have Separate Cells and how do Separate Cells work?
A
- Receptor cell synapses with first order neuron
- Located in retina (photoreceptors), inner ear (hair cells), and taste buds
22
Q
Functional groups of Receptors
A
Mechanoreceptors Nociceptors Photoreceptors Chemoreceptors Osmoreceptors
23
Q
Detect mechanical pressure; provide sensations of touch, pressure, vibration, proprioception, and hearing and equilibrium.
- Also monitor stretching of blood vessels and internal organs
A
Mechanoreceptors
24
Q
Respond to painful stimuli resulting from physical or chemical damage to tissue
A
Nociceptors
25
Detect light that strikes the retina of the eye
Photoreceptors
26
Detect chemicals in mouth (taste), nose (smell), and body fluids
Chemoreceptors
27
Sense the osmotic pressure of body fluids
Osmoreceptors
28
What do the Tactile sensations include?
- Touch
- Pressure
- Vibration
- Itch
- Tickle
29
Within the tactile sensations, what type of receptors detect touch, pressure, and vibration?
Encapsulated Mechanoreceptors (Encapsulated need more of a robust stimulus)
30
Tactile sensations such as itch and tickle are detected by?
Free Nerve endings (more sensitive to lighter stimulus)
31
Tactile receptors in the skin or subcutaneous layer include ?
Meissner corpuscles, hair root plexuses, Merkel discs, Ruffini corpuscles, pacinian corpuscles, and free nerve endings
32
What are the two touch receptors?
Meissner Corpuscles and Hair Root Plexuses
| * Rapidly adapting*
33
What is a Corpuscle?
An egg-shaped mass of dendrites enclosed by a capsule of connective tissue
34
Where are Meissner Corpuscles located and most abundant?
Located in dermal papillae or hairless skin
Most abundant:
Finger tips, hands, eyelids, tip of the tongue, lips, nipples, soles, clitoris, and tip of penis
35
What do Hair Root Plexuses consist of?
Free nerve endings wrapped around their hair follicles
36
What is the main job of a Hair Root Plexus and an example of that action?
Detect movements on the skin surface that disturb hairs
Ex: an insect landing on a hair causes movement of the hair shaft that stimulates free nerve endings
37
What are the two types of Slowly adapting touch receptors?
* Merkel discs (aka Tactile discs or type I cutaneous mechanoreceptors)
* Ruffini corpuscles (type II cutaneous mechanoreceptors)
38
A sustained sensation that is felt over a larger area and occurs in deeper tissues than touch, occurs with deformation of deeper tissues?
Pressure
39
Receptors that contribute to sensations of pressure include?
- Meissner corpuscles
- Merkel discs
- Pacinian or Lamellated Corpuscle
40
What are some characteristics of Pacinian Corpuscles?
- Adapt rapidly
- Widely distributed throughout the body:
* Dermis and subcutaneous layer
* Tissues underlying mucous and serous membrane
* around Joints, Tendons, and Muscles
* Periosteum
* Mammary Glands, external genitalia
* Pancreas and Urinary bladder
41
In vibration sensation, how do the Meissner corpuscles and pacinian corpuscles detect vibrations differently?
Meissner - lower frequency vibrations
| Pacinian - higher frequency vibrations
42
What results from stimulation of free nerve endings by certain chemicals or because of a local inflammatory response?
Itch sensation
43
What chemical stimulates an Itch sensation
Bradykinin
44
PT's who have had a limb amputated may still experience sensations such as itch, tingling, or pain as if the limb was still there. What is the name of this phenomenon?
Phantom Limb Sensation
45
Thermoreceptors have what type of receptors?
Free nerve endings
46
What temperatures activate Cold Receptors and where are they located?
Temps between 10 deg to 40 deg C (50-105F)
| - Epidermis
47
What temperatures activate Warm Receptors and where are they located?
Temps between 32 and 48 deg C (90-118F)
| - Dermis and Epidermis
48
What happens to cold and warm receptors throughout a stimulus?
They both adapt RAPIDLY at the onset of a stimulus but continue to generate nerve impulses more SLOWLY through prolonged stimulus
49
Temperatures below 10deg C and above 48deg C stimulate?
Nociceptors producing a painful sensation to extremes
50
What type of receptors do Nociceptors have and where are they found?
- Free nerve endings
| Found in every tissue BESIDES THE BRAIN
51
The lack of adaptation of Nociceptors is important because?
It serves a protective function
| - If adaptation occurred, irreparable tissue damage could occur
52
What are the two types of Pain?
Fast and Slow
53
Fast Pain
- Known as acute, sharp, or prickling (Knife cut or needle puncture)
The perception of fast pain occurs very rapidly
- within 0.1 sec after stimulus
54
T/F Fast Pain is felt in deeper tissues of the body
False. Slow pain is
55
Slow Pain
Felt a second or more after stimulus
- Gradually increases intensity over time
- Referred to as Chronic pain
- Can be burning, aching, or throbbing pain (toothache)
56
Where is Slow Pain felt?
Skin, Deeper tissues, and internal organs
57
How is the localization of Fast and Slow pain different?
Fast pain - precisely localized to the stimulated area
Slow pain - somewhat localized but more DIFFUSE
58
What is Referred Pain?
Pain felt in or just deep to the skin that overlies the stimulated organ.
- Or in a surface area far from the stimulated organ
59
What causes Referred pain to be felt in a surface area far from the site of stimulation?
The same segment of the spinal cord usually serves the visceral organ involved and the area of pain
60
What is pain that persists for longer than two or three months?
Chronic Pain
61
What allows us to know where our head and limbs are located and how they are moving even if we are not looking at them?
Proprioceptive Sensations
62
Kinesthesia
Perception of body movements
63
Where are proprioceptors located?
- Skeletal Muscles (Muscle spindles)
- Tendons (Tendon Organs)
- Synovial Joints (joint kinesthetic receptors)
- Inner Ear (hair cells)
64
What proprioceptors monitor the orientation of the head relative to the ground and positioning during movements?
Hair Cells in the inner ear
65
Where do nerve impulses for conscious proprioception travel?
Through tracts in the spinal cord and brain stem then relayed to:
PRIMARY SOMATOSENSORY AREA
(Post central Gyrus)
66
The study that deals with the eye and its disorders?
Ophthalmology
67
The science that deals with the Ears, Nose, and Throat and their disorders
Otorhinolaryngology
68
What is the term for smell and how many receptors are involved?
Olfaction
10-100 million receptors in the nose
69
What occupies the upper portion of the nasal cavity?
Olfactory Epithelium
70
What are the 3 types of cells in the Olfactory Epithelium?
- Olfactory Receptors
- Supporting Cells
- Nasal Stem Cells
71
What are the first-order neurons of the Olfactory pathway?
Olfactory Receptors
72
What projects from a knob-shaped tip on each olfactory receptor?
Olfactory hairs
73
Chemicals that have an odor and can therefore stimulate the olfactory hairs?
Odorants
74
The axons of the olfactory receptors extend from the olfactory Epithelium to the?
Olfactory Bulb
75
Columnar Epithelial Cells of the mucous membrane lining the nose
Supporting Cells
76
What do the Supporting Cells do?
Provide physical support, nourishment, and electrical insulation for the olfactory receptors and help detoxify chemicals that come in contact with the olfactory epithelium
77
Stem cells located between the bases of supporting cells and continually undergo cell division to produce new olfactory Receptors
Basal Cells
78
Why is the process of Basal cells producing olfactory receptors significant?
Olfactory Receptors are neurons and in general, mature neurons are not replaced
79
What produces mucus that moistens the surface of the olfactory epithelium and serves as a solvent for inhaled odorants?
Olfactory glands
80
How does adaptation occur to odors by olfactory receptors?
Adaptation (decreasing sensitivity) to odors rapidly.
Olfactory receptors adapt by 50% in the first second or so after stimulation and very slowly after that.
81
Which types of cells for the Olfactory Nerves (I)?
40 bundles of UNMYELINATED axons of olfactory receptors that extend through the cribiform plate of the ethmoid bone.
82
Where do the Olfactory Nerves terminate?
The olfactory bulbs (paired masses of gray matter), located below the frontal lobes of the cerebrum
83
How do neurons connect within the olfactory bulbs?
The axon terminals of olfactory receptors (1st Order neurons) form synapses with the dendrites and cell bodies of 2nd order neurons in the olfactory pathway
84
What forms the Olfactory tract?
The axons of the neurons extending from the olfactory bulb
85
At what location does the conscious awareness of smell begin?
The Primary Olfactory area
| - Temporal Lobe of Cerebral Cortex
86
What two locations does the olfactory tract project to?
- Primary Olfactory Area
| - Limbic System and Hypothalamus
87
What is Hyposmia?
Reduced ability to smell
| - Affects half of those over 65 yo, and 75% of 80yo
88
What are the 5 primary tastes?
1. Sour
2. Sweet
3. Bitter
4. Salty
5. Umami
89
How do odors of food affect taste?
Olfaction can be stimulated thousands of time more strongly than gustation.
- When you have a cold or allergies, and cannot taste food, it is olfaction that is blocked not gustation
90
Where are the receptors for taste sensation found in?
Taste buds
91
T/f: The number of taste buds declines with age
True
92
Elevations of the tongue where taste buds are found, and provide a rough texture to the tongue?
Papillae
93
Inverted V-shaped row of papillae at the back of the tongue
Vallate papillae
94
Mushroom shaped elevations scattered over the entire surface of the tongue
Fungi-form papillae
95
Threadlike papillae found in the entire surface of the tongue that contain touch receptors, but no taste buds
Filiform papillae
96
Three types of Epithelial cells in Taste Buds
1. Supporting Cells
2. Gustatory Receptor Cells (50)
3. Basal Cells
97
What projects from each gustatory receptor cell to the external surface through the taste pore?
Gustatory hair
98
What do the Basal Cells do within the taste bud?
Produce supporting cells, that develop into Gustatory Receptor Cells
99
How long is the life span of a Gustatory Receptor Cell?
10 days
100
How do Gustatory Receptor Cells send signals?
The are separate cells (No axon) so they SYNAPSE with dendrites of the first order sensory neurons
101
Chemicals that stimulate gustatory receptor cells
Tastants
102
Once a tastant dissolves in saliva, how does a signal travel to the Cranial nerve?
1. Tastant dissolves in saliva and enters taste pores making contact with Gustatory hairs
2. Electrical impulse is generated releasing neurotransmitters from Gustatory Receptor Cell
3. Neurotransmitters bind with receptors of 1st order neurons
103
Complete adaptation to a specific taste can occur in?
1 - 5 min of continuous stimulation
104
Which Cranial Nerves innervate the taste buds?
VII - Facial Nerve (anterior 2/3 sweet salty)
IX - Glossopharyngeal (posterior 1/3 bitter sour)
X - Vagus (throat and epiglottis)
105
Describe the Gustatory Pathway
1. From Taste Buds to Cranial Nerves
2. Cranial Nerves to Medulla
3. Medulla --- some split and go to the hypothalamus and limbic system. Others go to the thalamus and up to the Primary Gustatory Area
106
Where is the Primary Gustatory Area located?
Parietal lobe of the Cerebral cortex
107
More than half of all sensory receptors are located?
Eye
108
Accessory Structures of the Eye
Eyebrows, Eye lashes, Eyelids, Extrinsic muscles that move the eye balls, and lacrimal apparatus.
109
Which accessory structures help protect the eyeballs from foreign objects, perspiration, and UV rays?
Eyebrows and Eyelashes
110
Function of the eyelids
- Shade eyes during sleep
- Protect eyes from excessive light and foreign objects
- Spread lubricating secretions (blinking)
111
What are the Six extrinsic eye muscles?
Superior Rectus, Inferior Rectus, Medial Rectus, Lateral Rectus, Superior Oblique, and Inferior Oblique
112
What Cranial Nerves control the six extrinsic eye muscles?
Lateral Rectus - VI
Superior Oblique - IV
Medial Rectus, Inferior Oblique, Inferior and Superior Rectus - III
113
Group of glands, ducts, canals, and sacs that produce and drain lacrimal fluid or tears
Lacrimal Apparatus
114
Describe the flow of tears
1. Lacrimal glads secrete
2. through Lacrimal duct, and on to the eye
3. drain through Superior/Inferior Lacrimal canal
4. collect in the Lacrimal sac
5. drain through the Nasolacrimal duct
6. into the Nasal Cavity
115
How do tears drain?
Toward the nose into two lacrimal canals and a nasolacrimal duct; finally into nasal cavity
116
What are tears made of?
Lysozyme (Bacteria killing)
Salts
Mucus
117
Function of tears
Clean, lubricate, and moisten exposed eyeball
118
What are the three layers of the eyeball
Fibrous Tunic
Vascular Tunic
Retina
119
Outer coat of the eyeball
Fibrous tunic
120
What does the Fibrous Tunic consist of?
Cornea (anterior)
Sclera (posterior)
Conjunctiva
121
Transparent, fibrous coat that covers the colored iris.
Cornea
122
What is the main job of the Cornea?
Helps focus light rays onto the retina
123
The "white" of the eye, a coat of dense connective tissue that covers all of the entire eyeball except the cornea
Sclera
124
What is the main function of the Sclera
Gives shape to the eyeball, makes it more rigid, and protects its inner parts
125
An epithelial layer that covers the sclera but not the cornea and lines the inner surface of the eyelids
Conjunctiva
126
What is the Vascular Tunic comprised of?
Middle layer of the Eyeball and consists of:
Choroid
Ciliary Body
Iris
127
Thin membrane that lines most of the internal surface of the sclera
Choroid
128
What does the Choroid do?
- Contains blood vessels that nourish the eye
| - Contains melanocytes that produce the pigment melanin (causes this layer to be brown in color)
129
What is the main function of Melanin?
Absorbs stray light rays which prevents reflection and scattering of light within the eyeball.
* Results in a sharp and clear image cast on the retina by the cornea
130
What does the Choroid turn in to at the front of the eye?
Ciliary body
131
What does the Ciliary body consist of?
Ciliary processes
| Ciliary muscle
132
What does the ciliary process do?
Secretes Aqueous Humor
133
What is the job of the ciliary muscle?
Alters the shape of the lens for viewing objects up close or at a distance
134
A transparent structure that focuses light ryas onto the retina and is constructed of many layers of elastic protein fibers
Lens
135
What attaches the lens to the ciliary muscle and holds the lens into position?
Zonular fibers
136
The colored part of the eyeball and includes circular and radial smooth muscle fibers
Iris
137
The hole in the center of the iris, through which light enters the eyeball
Pupil
138
When stimulated by bright light, what part of the Autonomic Nervous System causes the circular muscles of the iris to constrict?
Parasympathetic division
139
When the eye adjusts to dim light, which part of the ANS causes the radial muscles to react and dilate?
Sympathetic division
140
T/f: During dilation of the pupils, the radial muscles RELAX allowing for the wider pupil
False, the radial muscles CONTRACT pulling the pupil wider in diameter
141
What structure is the beginning of the visual pathway
Retina
142
Two layers of the Retina
Neural layer
| Pigmented layer
143
What is the neural layer
Multilayered outgrowth of the brain
144
Three distinct layers of retinal neurons
Photoreceptor layer
Bipolar cell layer
Ganglion cell layer
145
What separates the retinal neurons
Outer and inner synaptic layers
146
What does light have to pass through before it reaches the photoreceptor layer?
Ganglion and Bipolar Cell Layers
| Both synaptic layers
147
Specialized cells that begin the process by which light rays are ultimately converted to nerve impulses
Photoreceptors
148
Two types of Photoreceptors
Rods and Cones
149
Photoreceptors that allow us to see shades of Gray in dim light
Rods
150
Photoreceptors the are stimulated by brighter lights, giving rise to acute Color Vision
Cones
151
Three types of Cones in the Retina
1. Blue cones
2. Green Cones
3 Red cones
152
How many Rods and Cones are in the eye?
6 million Cones
| 120 million Rods
153
Where are cones most concentrated?
Fovea centralis (small depression in the center of the macula
154
Macula lutea
Exact center of the Retina (Yellow Spot)
155
What is the area of highest visual acuity?
Fovea Centralis (high concentration of cones)
156
What is the main reason you move your head and eyes?
Place things of interest on the Fovea so you can see them clearly
157
What does the lens divide the interior of the eyeball?
Anterior Cavity
| Vitreous Chamber
158
Anterior cavity
Lies anterior to the lens and is filled with aqueous humor
159
A watery fluid similar to cerebrospinal fluid
Aqueous Humor
160
What secretes aqueous humor into the anterior cavity?
Blood capillaries of the ciliary processes of the ciliary body
161
Where does aqueous humor drain?
Scleral venous sinus (Canal of Schlemm)
| - and opening where the sclera and cornea meet and reenters the blood
162
What does the aqueous humor do?
Helps maintain the shape of the eye and nourishes the lens and cornea, neither of which have blood vessels
163
How often is aqueous humor replaced?
90 minutes
164
Which cavity is behind the lens and is the largest cavity of the eyeball?
Vitreous Chamber
165
What is the vitreous body?
A clear, jelly-like which forms during embryonic life and is not replaced thereafter.
- Helps prevent the eyeball from collapsing and holds the retina flush against the choroid
166
How is intraocular pressure produced?
Produced daily by the aqueous humor with a smaller contribution for the vitreous body.
- Also maintains shape and keeps retina pressed against the choroid for nourishment.
167
What is the NORMAL intraocular pressure and how is that maintained?
16 mmHg
| - Maintained by a balance between production and drainage of the aqueous humor
168
What is the bending of light in the eye called?
Refraction
169
About Seventy five % of the total refraction of light occurs where?
Cornea
170
Images focused on the retina are inverted and undergo right to left reversal. How does the brain correct this?
There brain stores the inverted and reversed images we acquire at a young age and "Learns" the proper orientations of objects
171
What is the difference in the reflection of light rays further and closer than 20 ft in relation to the Retina?
Over 6m: Light rays are parallel so the curvatures of the cornea can exactly focus on the retina
Closer than 6m: light rays are Divergent rather than parallel. Rays must be refracted more by changing the shape of the lens
172
T/f: Refraction occurs at the point where air meets water in the eye.
True
173
What 3 processes should occur for the eye to form clear images of objects on the retina?
1. The refraction of light by the lens and cornea
2. Change in shape of the lens
3. Constriction or narrowing of the pupil
174
The increase in the curvature of the lens for near vision
Accommodation
175
The normal eye, that con sufficiently refract light rays from an object at 6m (20 ft) away so that a clear image is focused on the retina
Emmetropic eye
176
Nearsightedness (can see nearby objects, but not distant objects), which occurs when the eyeball is too long relative to the focusing power of the cornea and lens
Myopia
177
Farsightedness, the eyeball length is short relative to the focusing power of the cornea or lens
Hyperopia
178
A refraction abnormality in which either the cornea or the lens has an irregular curvature
Astigmatism
179
With aging, the lens loses some elasticity so its ability to accommodate decreases.
Presbyopia
180
Which autonomic reflex occurs simultaneously with accommodation and prevents light rays from entering the eye through the periphery of the lens?
Constriction of the pupil
181
What would happen if light rays entered the periphery of the lens?
They would not be brought to focus on the retina and would result in blurred vision
182
Binocular vision
Both eyes focus on only one set of objects
183
What characteristics of vision does binocular vision give humans?
Depth perception and 3D nature of objects
184
As you move closer towards an object, your eyes automatically move towards the midline to refract light in comparable spots of the two retinas, this is called?
Convergence
185
A substance that can absorb light and undergo a change in structure
Photopigment (visual pigment)
186
Photopigment in Rods
Rhodopsin
187
How does Rhodopsin act with light vs. dark?
- Any Amt of light in a darkened room causes Rhodopsin to split into retinal and opsin, which initiates a chemical change in the rod.
- Rods become nonfunctional during the daylight, but in darkness retinal and opsin reform in to Rhodopsin to allow Rods to be used for night vision
188
Prolonged Vitamin A deficiency can cause?
Night blindness, which is a lack of rhodopsin
189
What is the Visual Pathway?
1. Rods and cones trigger electrical signal in Bipolar cells
2. Bipolar cells transmit excitatory and inhibitory signals to ganglion cells
3. The ganglion cells depolarized and generate nerve impulses
4. The axons of ganglion cells exit the eyeball as the OPTIC NERVE (II) and extend posteriorly to the optic chasm (crossover, X)
5. Passes the optic chiasm and becomes the Optic Tract which terminates in the Thalamus
6. Synapse with neuron whose axons project to the Primary Visual Area in the Occipital lobe
190
How is the ear divided?
External, middle, and inner ear
191
What is the function of the External ear?
Collects sound waves and channels them inward
192
What does the external ear consist of?
- Auricle
- External auditory canal
- Eardrum
193
The part of the ear you can see, a skin covered flap of elastic cartilage shaped like the flared end of a trumpet
Auricle (collects some sound waves)
194
A curved tube that extends from the auricle and directs sound waves toward the eardrum
External auditory canal
195
What does the Ceruminous Gland secrete within the External Auditory Canal?
Cerumen
196
What defenses help prevent foreign objects from entering the ear?
Hairs and Cerumen
197
A thin semitransparent partition between the external auditory canal and the middle ear?
Tympanic membrane
198
A small air-filled cavity between the ear drum and inner ear
Middle ear
199
Connects the middle ear with the upper part of the throat and helps equalize pressure
Eustachian tube
200
Three tiny bones that extend across the middle ear and are attached to it by ligaments
Auditory ossicles
201
What are the three bones that make up the auditory ossicles?
Malleus
Incus
Stapes
202
Which bone fits in to a small opening in the Oval Window?
Stapes
203
How is the Inner Ear divided?
Outer bony labyrinth
| Inner membranous labyrinth
204
What parts does the Bony Labyrinth contain
Cochlea
Vestibule
Semicircular canals
205
The sense organ for hearing (snail shell)
Cochlea
206
The sense organs for equilibrium and balance
Vestibule and Semicircular canals
207
What fluid is found in the bony labyrinth?
Perilymph
208
A series of sacs and tubes with the same general shape as the bony labyrinth, containing fluid called Endolymph
Membranous labyrinth
209
What fluid is found in the Membranous labyrinth?
Endolymph
210
The oval shaped middle part of the bony labyrinth
Vestibule
211
What does the membranous labyrinth in the vestibule contain?
Two sacs called:
- Utricle
- Saccule
212
Where are the 3 semi circular canals located?
Behind the vestibule
213
How are the three semicircular canals oriented?
Anterior and posterior canals - VERTICAL
| Lateral canal - HORIZONTAL
214
One end of each semicircular canal enlarges a swelling called?
Ampulla
215
The portions of the membranous labyrinth that lie inside the bony semicircular canals and connect with the utricle of the vestibule are?
Semicircular ducts
216
Looking at a transverse section of the Cochlea, how is it divided?
Three channels:
- Cochlear duct
- Scala Vestibuli
- Scala Tympani
217
What is a continuation of the membranous labyrinth into the cochlea and filled with endolymph?
Cochlear duct
218
The channel above the cochlear duct that ends at the oval window?
Scala vestibuli
219
The channel below the cochlear duct that ends at the round window
Scala tympani
220
What are both the Scala vestibuli and Scala tympani filled with?
Perilymph
221
What membrane is between the cochlear duct and the scala vestibuli?
Vestibular membrane
222
What membrane is between the cochlear duct and scala tympani?
Basilar membrane
223
What is the organ of hearing that rests on the basilar membrane?
Spiral Organ (Organ of Corti)
224
What does the Spiral organ consist of?
Supporting cells and hair cells
225
What is the function of the hair cells within the Spiral organ?
They are receptors for auditory sensations and extend into endolymph of the cochlear duct.
226
Which cranial nerve do the hair cells of the Spiral Organ synapse with
The COCHLEAR branch of CN VIII - Vestibulocochlear nerve.
227
What are the hair cells within the Spiral Organ covered with?
Tectorial Membrane - flexible gelatinous substance
228
When does the Auditory Pathway begin?
When the auricle catches external sound waves and channels them internally to the middle ear
229
Describe the auditory pathway once the sound is in the external canal
1. Sound waves brought in strike the eardrum causing vibration. The distance speed and movement depends on the intensity and frequency of sound waves
2. As sound waves are transmitted through the external to inner ear, electrical impulses are picked up by sensory neurons in the COCHLEAR branch of the Vestibulocochlear nerve (CN VIII).
* Those impulses are transmitted to the MEDULLA on the SAME SIDE of the brain.
3. From the medulla, axons ascend to the midbrain, then thalamus, and finally the primary auditory area in Temporal Lobe.
4. Auditory axons cross from both sides, the left and right auditory areas receive impulses from both ears.
230
What are the receptor organs of Equilibrium?
Vestibular Apparatus:
- Saccule
- Utricle
- Membranous semicircular ducts
231
The maintenance of the position of the body (mainly the head) relative to the force of gravity
Static equilibrium
232
What are body movements that stimulate Static equilibrium?
- Tilting the head
| - Linear acceleration/deceleration (elevator or riding in a car)
233
The maintenance of body position (mainly the head) in response to Rotational acceleration or deceleration
Dynamic equilibrium
234
What are the receptors for Static equilibrium?
the two Maculae found within the walls of the Utricle and Saccule.
235
What information do the Maculae provide?
Sensory info on the position of the HEAD in space and help maintain posture and balance
236
When the otoliths (stones) of the hair cells within the Maculae tilt during head position it triggers nerve impulses that conduct along?
VESTIBULAR branch of CN VIII
237
What detects information for Dynamic equilibrium?
The Ampulla that contains a small elevation called the Crista (has associated structures that create signals)
238
What within the Crista detects rotational movement?
Hair cells, supporting cells, and cupola (gelatinous) bend triggering nerve impulses through the Vestibular branch in CN VIII
239
Within the equilibrium pathway, which structures help in maintaining equilibrium?
VIII enters the brain stem and extends to the Medulla or Cerebellum
Eye movements, head and neck position, muscle tone regulation all aid in adjusting the body
240
Which is the key player in the Equilibrium pathway and where does it constantly receive information from?
The Cerebellum
| - Receives continuous sensory information from the UTRICLE and SACCULE
