Test 3 Objectives Flashcards
(161 cards)
1
Q
What are the bones of the middle ear from lateral to medial?
A
Malleus, incus, stapes
2
Q
What are the soft tissue windows the bones are attached to? Which bones attach to which windows?
A
- tympanic membrane: malleus
- vestibular window: stapes
3
Q
Hearing requires _____, localizing sound requires _____
A
At least 1 ear; 2 ears
4
Q
What muscle is attached to the malleus? Who innervates it?
A
Tensor tympani
- innervated by mandibular branch of CN 5
5
Q
What muscle is attached to the stapes? Who innervates it?
A
Stapedius
- innervated by CN 7
6
Q
Cochlear canaliculus
A
Connects boney labryinth to subarachnoid space of the brain
7
Q
What are 2 ways for an otitis media/interna to cause meningitis?
A
Infection has to get from the inner ear to the brain cavity
- facial nerve runs in the middle ear, so it’s possible to have facial nerve paralysis w/ an ear infection
- large infection in middle ear breaks down tissue, travels into brain via facial nerve or cochlear canaliculs
- common in young ruminants, and sometimes cats*
8
Q
What did the receptor organs of Dr. Little’s and Dr. Moore’s lectures have in common?
A
They are bipolar neurons
9
Q
Where are all the bipolar neurons in the body?
A
Sensory neurons found in the olfactory bulb, retina, and vestibularcochlear ganglia
10
Q
Who makes the endolymph of the cochlear duct?
A
Stria vascularis
11
Q
What is a mutation that is found in all white animals?
A
Stria vascularis malfunctions, leading to no endolymph
12
Q
Boney labryinth
A
Scala vestibuli and tympani filled with perilymph
- connected at end of cochlea by helicotrema
- separated from cochlear duct by the vestibular membrane and the basilar membrane
13
Q
What membrane does the organ of Corti live on? What scala does that separate the cochlear duct from?
A
Basilar membrane; scala tympani
14
Q
What is the organ of Corti?
A
Sensory receptors for hearing
- within the cochlear duct
- cochlear nerve innervates sensory cells
15
Q
Sound waves in the inner ear
A
Physical waves in perilymph via ossicles
- deforms hair cells –> opens mechanically gated K channels = depolarizing hair cells
16
Q
What lemniscus carries sound information toward which colliculus?
A
Lateral lemniscus > caudal colliculus
- lateral lemniscus –> caudal colliculus –> medial geniculate nucleus –> auditory cortex of the temporal lobe
17
Q
What did the medial lemniscus carry?
A
All sensory input from the spinal cord
18
Q
What pathway is used for the acoustic reflex?
A
Medial tectospinal tract
- reflex requires rostral colliculus
- LMN brainstem and cervical spine
- turns head and eyes toward sound*
19
Q
How do you test for hearing in a dog?
A
BAER
- brainstem auditory evoked response
- delivers clicks via specialized earplugs
- don’t test until 6-8 weeks as auditory apparatus has not matured yet!
20
Q
Counduction deafness
A
Middle or external hearing loss due to:
- occlusion of external ear
- rupture of tympanic membrane
- objects in middle ear
- damage or stiffening of ossicles
21
Q
Sensorineural deafness
A
Inner ear auditory structures or pathways damaged
- cochlea, vestibulocochlear nerve or brain
- commonly hair cell dysfunction in organ of Corti
22
Q
What kind of deafness would an old dog have?
A
Conduction
23
Q
What kind of deafness would a Dalmatian have? From loss of the stria vascularis and hair cell death
A
Sensoineural
24
Q
What nerves besides the auditory portion of CN 8 are affected with otitis media/interna?
A
- CN 7
- sympathetic nerves
- CN 8 (vestibular)
25
Otitis media/interna
Could be conduction or sensorineural
- commonly from extension of otitis externa
- could be due to strep, staph, pseudomonas (need to culture)
- treat with long term systemic antibiotics
26
What portion of the cortex is olfactory sensation sensed?
Rhinencephalon (piriform lobe)
- includes: olfactory bulb, olfactory tract, lateral olfactory gyrus, piriform lobe
- localization of food, reflex stimulated secretions of digestive enzymes, detection of danger, mating
27
What area of the brain is involved in emotional reactions to smell?
Limbic system
| - includes: amygdala, septal nuclei, hippocampus, entorhinal cortex
28
What area of the brain is involved in reflex response to smell?
Hypothalamus
| - periaqueductal gray to CN nuclei for salivation and release of digestive enzymes
29
What 2 pathways are leaving the olfactory bulb?
Medial and lateral olfactory tract
30
What pathway crosses midline?
Medial
31
What pathway goes to the piriform lobe for perception of smell?
Lateral
32
Which goes to the limbic system for emotional response to smell?
Both
33
Medial olfactory tract pathway
Left and right side communicate to each other
- info enters thru rostral commissure --> projects to contralateral (opposite) bulb
- what you smell on the right side is perceived on the left
34
Lateral olfactory tract pathway
Stays ipsilateral and goes to piriform lobe of the cerebral cortex for smell
- may also synapse on hippocampus for emotional response
35
What is different about the somatosensory sensation of smell vs all other somatosensory systems?
Does not go to the thalamus!!
36
What CN supplies taste to the rostral tongue?
CN 7
| - geniculate ganglion
37
What CN supplies taste to the caudal tongue?
CN 9
| - distal ganglion of CN 9
38
What CN supplies taste to the pharynx/larynx?
CN 10
| - distal ganglion of CN 10
39
Where are taste receptors located?
Soft palate, pharynx, larynx, lips and cheeks
40
What nerves innervate which taste buds?
- fungiform: CN 7
- foliate: CN 7
- valiate: CN 9
41
What are the channels for taste?
- salt/sour: opens channels directly
| - bitter/sweet: G protein coupled before channel is opened
42
What brainstem nucleus are gustatory CN going to? What area of the brainstem is it in?
```
Solitary tract (gustatory) nucleus
- medulla oblongata
```
43
What else goes to the solitary tract nucleus?
Chemoreceptors, baroreceptors
44
What is the pathway from the nucleus in the in the brainstem to the thalamus?
Solitariothalamic tract
45
What are the components of the inner ear for (and what are their receptor organs)
```
Sound: organ of Corti
Movement: hair cells
- urticle: macula (horizonal movement)
- saccule: macula (vertical)
- semicircular ducts: crista ampullaris (directional change, speed, rotation, transient head movement)
```
46
What are the descending tracts from the vestibular nuclei? What clinical sign do they cause with disease in the vestibular system?
- medial vestibulospinal tract: head tilt (ipsilateral neck and shoulders)
- lateral vestibulospinal tract: falling (ipsilateral spinal LMN)
47
What are the ascending tracts from the vestibular nuclei? What clinical signs do they cause with disease in the vestibular system?
Medial longitudinal fasciculus
- nystagmus
- innervates oculomotor, trochlear, and abducens nerves
48
Vestibular nuclei have reciprocal connections with the _____ and _____
Ipsilateral flocculonodular lobe and contralateral vestibular nuclei
49
Which nystagmus is normal?
Physiologic and pendular
50
Physiological nystagmus
Vestibulo-ocular reflex
- slow phase during head movement opposite to rotation
- fast phase when eyes reach limit of movement and return to central position
51
Gait
Vestibular nuclei excited --> ipsilateral extensors and contralateral flexor activated
- both sides should normally balance each other
- if not working you get a head tilt, falling/rolling, circling
52
Is a spontaneous or positional nystagmus normal?
No, both indicate pathological nystagmus
53
What are the signs of vestibular disease?
- nystagmus (fast phase away from the lesion)
- falling (ipsilateral)
- circling (ipsilateral)
- head tilt (ipsilateral)
54
What is a differentiating factor in determining central vs peripheral vestibular disease?
Proprioception
- peripheral: normal proprioception
- central: abnormal proprioception
55
What signs are added for peripheral vestibular disease? Where does this mean the lesion is?
Should not have postural reaction deficits or paersis for PVD
- will have Horner's syndrome and facial deficits
- located in middle or inner ears
56
What signs are added for central vestibular disease? Where does this mean the lesion is?
- postural reaction deficits
- paresis
- lesion is in the brainstem nuclei or cerebellum
57
Your patient has a head tilt to the right, circling to the right and fast phase of nystagmus to the left but the postural reaction deficits are on the left, where is the lesion?
Left paradoxical
- CNS goes with postural reaction deficits
- lesion in cerebellum
58
Your patient has a head tilt to the right, circling to the right, and nystagmus fast phase to the left. Is the patient central or peripheral vestibular syndrome?
Do not have any qualifiers, can't tell
| - right sided vestibular disease, can't guarantee where the lesion is
59
Bilateral vestibular disease
- peripheral
- no nystagmus or head tilt
- crouched stance, tentative gait
- wide side to side head excursions
60
Central vestibular disease
- mentation: altered
- gait/posture: vestibular ataxia +/- paresis and postural deficits
- CN: head tilt, nystagmus (vertical and shifting, positional), strabismus, CN deficits in addition to/including other than CN 7 and 8
- no Horner's
- may have postural reaction deficits
61
Peripheral vestibular disease
- mentation: alert, nausea/vomiting
- gait/posture: vestibular ataxia, no paresis or proprioceptive deficits
- CN: head tilt, nystagmus, strabismus, CN 7 dysfunction
- horners syndrome
- normal postural reactions
62
Your patient has a head tilt to the left, circling to the left, nystagmus fast phase to the right, Horner's syndrome in the left eye. Where is the lesion? What is affected to create the Horner's syndrome?
Peripheral, left-sided lesion
| - Horner's is taking out sympathetic nerve (CN 7)
63
Your patient has a head tilt to the right, circling to the right, nystagmus fast phase to the left, right sided postural reaction deficits and right sided facial nerve paralysis. Where is the lesion?
Central, right sided lesion
| - postural reaction deficits tell you its central!!
64
Peripheral signs summary
- vestibular taxia: yes
- list/lean/fall/roll: ipsilateral
- head tilt: ipsilateral
- pathologic nystagmus: yes (horizontal or rotatory)
- changing nystagmus: no
- positional strabismus: yes
- mentation changes: no
- postural rxn deficits: no
- paresis: no
- CN deficits: 7 and 8 only
65
Central signs summary
- vestibular taxia: yes
- list/lean/fall/roll: ipsilateral
- head tilt: ipsilateral
- pathologic nystagmus: yes (vertical, more central)
- changing nystagmus: possible
- positional strabismus: yes
- mentation changes: possible
- postural rxn deficits: possible (usually ipsilateral)
- paresis: yes (ipsilateral)
- CN deficits: possible (5-12)
66
Paradoxical signs summary
- vestibular taxia: yes
- list/lean/fall/roll: contralateral
- head tilt: contralateral
- pathologic nystagmus: yes (vertical, central)
- changing nystagmus: possible
- positional strabismus: yes
- mentation changes: possible
- postural rxn deficits: possible (ipsilateral)
- paresis: yes (contralateral)
- CN deficits: possible (5-12)
67
Who is the supreme overseer of the ANS?
Hypothalamus
68
Where is the preganglionic cell body of the SANS? PANS?
- SANS: thoracolumbar (T1-L4/5)
| - PANS: craniosacral (branstem nuclei = CN 3, 7, 9, 10, 11)
69
_____ regulating the SANS has the same effect as _____ regulating the PANS
Up; down
70
What neurotransmitter is released at the preganglionic synapse?
Ach for both SANS and PANS
- act upon Ach nicotinic receptors
- everyone shares the same first neurotransmitter and first receptor
71
Where is the cell body of the somatic motor system located?
Ventral gray matter of the ventral horn in spinal cord
| - also releases Ach to act on Ach nicotinic receptors on muscle cells
72
What does the postganglionic neuron release in the SANS/PANS?
- SANS: norepinephrine/epinephrine
- -> receptors: beta and alpha adrenergic
- PANS: Ach
- -> receptors: muscarinic
73
Preganglionic fibers are ____, postganglionic fibers are _______
Myelinated; nonmyelinated
74
Which axon is longest (preganglionic or postganglionic) for the SANS? PANS?
- SANS: postganglionic
| - PANS: preganglionic
75
The sympathetic chain
Located just ventral to the thoracolumbar spinal column
| - made up of inter-connected paravertebral ganglia
76
Where are the postganglionic cell bodies located for SANS innervation to the eye?
Cranial cervical ganglia
| - lesion here could give Horner's
77
What cranial nerves supply PANS to the head?
CN 3, 7, 9, 10
78
Who supplies PANS innervation to the thorax and cranial abdomen?
CN 10
79
Who supplies SANS innervation to the caudal abdomen?
Splanchnic nerves
80
Who is fight or flight?
SANS
81
Who is rest and digest?
PANS
82
Which connects to the adrenal gland? SANS or PANS
SANS
83
How do fibers from the thoracolumbar SANS get to the areas cranial or caudal to these spinal cord segments?
Sympathetic trunk
84
What is the ganglion for SANS to the bladder?
Caudal mesenteric
85
What makes the pupil constrict? What is the ganglion for this called? What is the postganglionic nerve called?
PANS (CN 3)
| - ciliary ganglia, short ciliary nerve
86
What makes the pupil dilate?
SANS
87
What makes you salivate?
CN 7, 9 for the mandibular, sublingual, parotid, zygomatic salivary glands
88
Cranial cervical ganglion
Post ganglionic fibers innervate smooth muscle, salivary, lacrimal glands
89
Middle cervical ganglion
Innervate cardio-sympathetic system
90
Cervical thoracic ganglion
Sends postganglionic fibers to the heart and cervical spinal nerves of C3 via communicating branches
91
Which fibers do not synapse in the sympathetic trunk?
T6-T12 or L1-3
- descend the cord and exit as either splanchnic nerves and terminate in ganglia near the aorta (T6-12)
- become lumbar splanchnic (L1-3)
92
Dysautonomia
Selectively affects the entire ANS
- both SANS and PANS are affected
- loss of pre and postganglionic cell bodies
93
Orbicularis oculi dysfunction
Inability to blink
94
All sensation of the eye comes from the
Trigeminal nerve
95
What are the 3 nuclei of the eye?
- oculomotor nuclei: parasympathetic nucleus 3 and motor nucleus 3
- trochlear nucleus: motor nucleus 4
- abducens nucleus: motor nucleus 6
96
Where are the nuclei located?
Oculomotor and trochlear: midbrain
| Abducens in the medulla
97
Medial longitudinal fasciculus
Extraocular muscles
- conjugate muscles
- eyes do not function independently
- controlled by MLF
98
Dorsal rectus
Elevates globe
| - CN 3
99
Ventral rectus
Depresses globe
| - CN 3
100
Medial rectus
Turns globe medially
| - CN 3
101
Lateral rectus
Turns globe laterally
| - CN 6
102
Ventral oblique
```
Extorts globe (rotates 12 o'clock position temporarily)
- CN 3
```
103
Dorsal oblique
```
Intorts globe (rotates 12 o'clock position nasally)
- CN 4
```
104
Retractor bulbi
Retracts globe
| - CN 6
105
If you had been in a car accident and had to have one of the 2 pupil descriptions, which one would you want to have? Bilateral fixed and dilated or bilateral miosis?
Bilateral miosis
106
CN 3
DVM rectus, ventral oblique
| - midbrain
107
CN 4
Dorsal oblique
| - midbrain
108
CN 6
Lateral rectus, retractor bulbi
| - brainstem
109
Strabismus
Abnormal position of eyes, neurologic, mechanical issues
- ventrolateral: CN 3 dysfunction
- medial: CN 6 dysfunction
- dorsolateral: CN 4 dysfunction
110
Upper eyelid drooping
- ptosis: CN 7, levator, oculi, ventris and CN 3 levator palpebral
- sympathetic: mullers muscles
111
Sensory innervation to eyelid
CN 5
- opthalmic medial canthus
- maxillary lateral canthus
112
Motor innervation to close eyelid
CN 7, orbicularis oculi
113
Neuroparalytic KCS
CN 7 paralysis
- lacrimal dysfunction, occurs with or without motor portion of CN 7
- ipsilateral dry nose
114
Neurotrophic keratitis
CN 5 issues
| - keratitis due to inability to blink
115
Palpebral reflex
Medial: opthalamic branch of CN 5
Lateral: maxillary CN 5
116
Corneal reflex test
CN 5 and 6
117
Palpebral reflex
CN 5 and 7
118
Menace response
CN 2 (to see) and 7 (to blink)
119
Photoreceptors of retina
- rods: night, motion
| - cones: day, color
120
The optic nerve is a _____
Tract!!
121
Axons from right visual field hit the medial retina of the ________
Right eye
- lateral retina of the left eye
- course through the lateral geniculate nucleus (in thalamus) and the left occipital lobe
122
% decussation
- people: 50
- birds: 100
- dogs: 75
- cats: 65
- farm animals: 75-80
123
What percent of fibers branch off the optic tract to influence pupillary light reflexes? Where are they going?
20%
| - pretectal nucleus
124
Visual pathway
Visual field --> retina --> optic nerve --> optic chiasm
| --> optic tract --> lateral geniculate nucleus --> optic radiation --> visual cortex
125
Objects from the right half of the visual field are passed to the _____ cortex
Left
126
Does the pupillary light reflex after the LGN reach the cortex?
No
127
Will a disease of ______ cause vision deficits? PLR deficits?
- retina: yes, yes
- CN 2: yes, yes
- optic chiasm: yes, yes
- optic tract: yes, yes
- LGN: yes, no
- PANS: no, yes
- occipital cortex: yes, no
- CN 3: no, yes
- ciliary ganglion: no, yes
128
Which ANS causes miosis? Mydriasis?
- miosis: PANS
| - mydriasis: SANS
129
If you have a good PLR, can you skip a menace response?
No
130
What causes blindness, but a good PLR?
Cortical blindness
131
Direct PLR is _______ for animals due to more crossover
Stronger
132
Dazzle reflex
Shine a light in the eye and wait for blinking
- subcortical reflex
- optic nerve is intact but can't say that the dog is visual
133
Does the pupil constrict when light is shown in the opposite eye?
Yes, consensual (indirect)
- due to optic nerve
- controlled by PANS
134
Pupil innervation
CN 3
| - constrictor muscle (parasympathetic cholinergic) is stronger than pupillary dilator (sympathetic adrenergic)
135
Horner's syndrome
Ptosis, enopthalmia, 3rd eyelid elevation, miosis
136
What is different about horses?
Sweat on ipsilateral side of lesion
137
Why would you dim the light in the room with a patient with anisocoria?
If miotic, place in a dark room to watch for dilation
| - PANS
138
What could be mistaken for Horner's?
- internal/external opthalmoplegia --> mydriatic pupil, NOT mitotic
- cavernous sinus
- CN 3, 4, 5 opthalmic, 6
139
What drugs can be given to cause pupil dilation and pupil constriction in denervated pupil showing hypersensitivity?
- phenylephrine: dilate sympathomimetic
- pilocarpine: constrict parasympathomimetic
- atropine: dilates eye for 24 hrs
140
UMN and LMN bladders
Lost coordination somewhere
141
Which ANS causes miosis? Mydriasis?
PANS; SANS
142
If a pupil only constricts when light is shown in the other eye, but is dilated all the time where is the lesion?
Optic nerve
143
What ganglion does the PANS and SANS synapse on when traveling to the eye?
Cranial cervical
144
Sympathetic controls the ______ phase of micturition
Storage
| - thoracolumbar region
145
Parasympathetic controls actual ________
Micturition
| - craniosacral region
146
Pons micturition innervation
Pontine micturition center
- reticular formation
- storage and evacuation
- receives info from SC regarding bladder
- sends info to the bladder via spinal cord (reticulospinal tracts)
147
Cerebrum micturition innervation
Conscious control of micturition
148
Cerebellum micturition innervation
Inhibitory influence on micturition
149
Reticulospinal tract
Terminate in ventral horn gray matter
| - LMN to bladder
150
Pudendal nerve
Somatic innervation
- S1-S3
- Ach nicotinic receptor: simulation constricts external urethral sphincter
- sensory and motor to external urethral sphincter (skeletal)
151
Hypogastric nerve
Sympathetic innervation
- L1/L4 (dog), L2/L5 (cat)
- beta receptor: stimulation relaxes detrusor muscle to store urine
- alpha receptor: stimulation constricts internal urethral sphincter (smooth)
- sensory branch to perceive pain
- norepinephrine is the NT
152
Pelvic nerve
Parasympathetic innervation
- S1-S3
- Ach muscarinic receptor: stimulation contracts detrusor to evacuate urine
- sensory branches to sense bladder wall stretch and transmit info to pontomedullary micturition center
153
Sympathetic defecation
Input from hypogastric spinal cord segments
- innervates descending colon, rectum, and internal anal sphincter (smooth)
- excitatory to internal anal sphincter but inhibitory to descending colon and rectum
154
Parasympathetic defecation
Input from pelvic nerve spinal cord segments
| - innervates the descending colon and rectum (excitatory)
155
Somatic defecation
Input from pudendal nerve spinal cord
| - innervates striated muscle of external anal sphincter (excitatory)
156
UMN bladder
- great tone due to pelvic nerve
- turgid, firm
- difficult to express
- T3-L3 spinal cord lesion
157
LMN bladder
- poor tone/atonic
- lose, no external urethral sphincter
- easier to express
- L4-S2 spinal cord lesion
158
UMN is _____ caudal to lesion
Hypertonicity
- increased external urethral sphincter tone
- increased resting tone to detrusor
159
UMN bladder dysfunction due to
Loss of higher level coordination of detrusor/sphincter
| - cannot overcome resistance from external urethral sphincter
160
LMN lesion is ______
Hypotonicity of pelvic and pudendal nerves
- decreased external urethral sphincter tone
- decreased detrusor strength
161
LMN dysfunction due to
Inability to contract detrusor
| - dribbling due to inability to constrict sphincter
