2. Anatomy and Physiology 2 Flashcards
(174 cards)
1
Q
Neuromuscular junction This is the 2nd synapse in which spinal tract?
A
Lateral corticospinal tract
2
Q
Lower vs. Upper motor neuron lesion
A
Lower MN lesion = everything lowered (less muscle mass, decr muscle tone, decr reflexes, downgoing toes) Upper MN = everythinig up (tone, DTRs, toes)
3
Q
Spinal tract: UMN vs. LMN lesion: Weakness
A
Both
4
Q
What motor neuron sign is present in both UMN and LMN lesions?
A
Weakness
5
Q
Spinal tract: UMN vs. LMN lesion: Atrophy
A
Atrophy in LMN only
6
Q
Spinal tract: UMN vs. LMN lesion: Fasciculations (muscle twitching)
A
Present in LMN lesions only
7
Q
What motor neuron signs are only present in LMN lesions?
A
Atrophy and fasciculations/fibrillations
8
Q
Spinal tract: UMN vs. LMN lesion: Reflexes
A
Increased in UMN Decreased in LMN
9
Q
Does UMN/LMN lesions lead to increased, decreased or the same reflex?
A
UMN vs. LMN lesion: Reflexes
10
Q
Spinal tract: UMN vs. LMN lesion: Tone
A
Increased in UMN, decreased in LMN
11
Q
What is increased in UMN lesion but decreased in LMN?
A
UMN vs. LMN lesion: Tone
12
Q
Spinal tract: UMN vs. LMN lesion: Babinski sign (upgoing toes – normal in infants)
A
(+) in UMN, (-) in LMN
13
Q
What does Babinski sign suggest about lesion?
A
UMN
14
Q
Spinal tract: UMN vs. LMN lesion: Spastic paralysis
A
(+) in UMN (-) in LMN
15
Q
What lesion does clasp knife spasticity suggest?
A
UMN
16
Q
Spinal cord lesions: Poliomyelitis and Werdnig-Hoffmann disease What areas are affected? What are the Sx?
A
Lower motor neuron lesion only, due to destruction of anterior horns; flaccid paralysis
17
Q
Lower motor neuron lesion only, due to destruction of anterior horns; flaccid paralysis What diseases (2) are associated with this?
A
Poliomyelitis and Werdnig-Hoffmann disease
18
Q
Spinal cord lesions: Multiple sclerosis What areas are affected? What are the Sx?
A
Mostly white matter of cervical region; random and asymmetric lesions, due to demyelination; scanning speech, intention tremor, nystagmus
19
Q
Mostly white matter of cervical region; random and asymmetric lesions, due to demyelination; scanning speech, intention tremor, nystagmus What disease is associated with this?
A
Multiple sclerosis
20
Q
Spinal cord lesions: ALS What areas are affected? What are the Sx?
A
Combined upper and lower motor neuron deficits with no sensory deficit; both upper and lower motor neuron signs.
21
Q
Combined upper and lower motor neuron deficits with no sensory deficit; both upper and lower motor neuron signs. What disease is associated with this?
A
ALS
22
Q
Spinal cord lesions: Complete occlusion of the anterior spinal artery What areas are affected? What are the Sx?
A
Spares dorsal columns and tract of Lissauer; upper throacic ASA territory is a watershed area, as artery of Adamkiewicz supplies ASA below ~T8
23
Q
Spares dorsal columns and tract of Lissauer; upper throacic ASA territory is a watershed area, as artery of Adamkiewicz supplies ASA below ~T8 What disease is associated with this?
A
Complete occlusion of the anterior spinal artery
24
Q
Spinal cord lesions: Tabes dorsalis (tertiary syphilis) What areas are affected? What are the Sx?
A
Degeneration of dorsal roots and dorsal columns; impaired proprioception, locomotor ataxia
25
Degeneration of dorsal roots and dorsal columns; impaired proprioception, locomotor ataxia What disease is associated with this?
Tabes dorsalis (tertiary syphilis)
26
Spinal cord lesions: Syringomyelia What areas are affected? What are the Sx?
Crossing fibers of spinothalamic tract damaged (2nd order neuron); bilateral loss of pain and temperature sensation. (usually C8-T1); seen with Chiari I types 1 and 2; can expand and affect other tracts
27
Crossing fibers of spinothalamic tract damaged; bilateral loss of pain and temperature sensation. What disease is associated with this?
Syringomyelia
28
Spinal cord lesions: Vitamin B12 neuropathy, Vitamin E deficiency and Friedrich's ataxia What areas are affected? What are the Sx?
Demyelination of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts; ataxic gait, hyporeflexia, impaired position and vibration sense.
29
Demyelination of dorsal columns, lateral corticospinal tracts, and spinocerebellar tracts; ataxic gait, hyperreflexia, impaired position and vibration sense. What diseases (3) are associated with this?
Vitamin B12 neuropathy, Vitamin E deficiency and Friedrich's ataxia
30
Poliomyelitis: Cause and Transmission?
Cause: poliovirus (fecal-oral) and replicates in oropharynx and small intestines -\> spreads through bloodstream to CNS -\> destruction of cells in anterior horn of spinal cord, leading in turn to LMN destruction.
31
Poliomyelitis: Sx?
Malaise, hedache, fever, nausea, abdominal pain, sore throat. Signs of LMN lesions -- muscle weakness and atrophy, fasciculations, fibrillation, and hyporeflexia.
32
Poliomyelitis: Findings?
CSF w/ lymphocytic pleocytosis w/ slight elevation of protein (w/ no change in CSF glucose). Virus recovered from stool or throat.
33
Werdnig-Hoffman dz. Genetics, Presentations and Prognosis
Infantile spinal muscular atrophy; Autosomal-recessive inheritance; presents at birth as a "floppy baby," tongue fasciculations; median age of death 7 months. Associated w/ degeneration of anterior horns. LMN involvement only.
34
Amyotrophic lateral sclerosis (commonly known as Lou Gehrig's dz). Clinical presentation, genetics, treatment.
Associated with LMN and UMN signs; no sensory, cognitive or oculomotor deficits. Can be caused by superoxide dismutase 1 (SOD1). Commonly presents as fasciculations and eventual atrophy; progressive and fatal. Riluzole treatment modestly lengthens survival by decreasing presynaptic glutamate release; associated with betel nut ingestion.
35
Tabes dorsalis. Etiology and Clinical presentations.
Degeneration of dorsal columns and dorsal roots due to tertiary syphilis, resulting in impaired proprioception and locomotor ataxia. Argyll Robertson pupils
36
Associated with Tabes dorsalis
Charcot's joints (neuropathic arthropathy), Shooting (lightning) pain, Argyll Robertson pupils (accomodate, but do not react), Absence of deep tendon reflexes, positive Romberg, sensory ataxia at night.
37
Friedrich's ataxia: Genetics, Etiology, and Presentation
Autosomal-recessive trinucleotide repeat disorder (GAA) in frataxin gene -\> impairment in mitochondrial functioning; staggering gait, frequent falling, nystagmus, dysarthria, pes cavus (high arch), hammer toes, hypertrophic cardiomyopathy (cause of death). Presents in childhood with kyphoscoliosis.
38
Brown-Séquard Syndrome: What is it?
Hemisection of the spinal cord
39
Brown-Séquard Syndrome: Findings?
1.) Ipsilateral UMN signs (corticospinal tract) below lesion 2.) Ipsilateral loss of tactile, vibration, proprioception sense (dorsal column) below lesion 3.) Contralateral pain and temperature loss (spinothalamic tract) below lesion 4.) Ipsilateral loss of all sensation at level of lesion 5.) LMN signs (e.g., flaccid paralysis) at level of lesion
If lesion occurs above T1, presents w/ Horner's syndrome
40
Horner's syndrome. Symptoms and Etiology.
Sympathectomy of face: 1.) P tosis (slight drooping of eyelid) 2.) A nhidrosis (absence of sweating) and flushing (rubor) of affected side of face 3.) M iosis (pupil constriction)
Associated w/ lesion of spinal cord above T1 (e.g., Pancoast (pulmonary sulcus) tumor, Brown-Séquard syndrome (cord hemisection), late-stage syringomyelia)
41
3-Neuron oculosympathetic pathway involved in Horner's syndrome
1. Hypothalamus -\> intermediolateral column of spinal cord; synapse in lateral horn (T1)
2. Second neuron projects to up sympathetic trunk to superior cervical ganglion (C2)
3. Third neuron sends projects along external carotid artery to sweat glands of face, along opthalmic division of trigeminal nerve to smooth muscles of eyelids and pupillary dilator.
Interruption of any of these pathways result in Horner's syndrome.
42
Clinically important landmarks for a pudendal nerve block (to relieve pain of pregnancy)
Ischial spine
43
Clinically important landmarks for Appendix
2/3 of the way from the umbilicus to the anterior superior iliac spine (McBurney's point)
44
Clinically important landmarks for lumbar puncture
Iliac crest.
45
Landmark dermatomes: C2
Posterior half of a skull "cap"
46
Landmark dermatomes: C3
High turtleneck shirt
47
Landmark dermatomes: C4
Low-collar shirt
48
Landmark dermatomes: T4
At the nipple. (T4 at the teat pore )
49
Landmark dermatomes: T7
Xiphoid process
50
Landmark dermatomes: T10
At the umbilicus (important for early appendicitis pain referral) (T10 at the belly butTEN )
51
Landmark dermatomes: L1
At the inguinal ligament ("L1 is IL [I nguinal L igament])
52
Landmark dermatomes: L4
Includes kneecaps
53
Landmark dermatomes: S2, S3, S4
Erection and sensation of penile and anal zones ("S2, 3, 4, keep the penis off the floor")
54
Muscle spindles vs. Golgi tendon organs
Muscle spindles monitor muscle length (help you pick up a heavy suitcase when you didnt know how heavy it was). Golgi T endon organs monitor muscle T ension (make you drop a heavy suitcase you've been holding too long).
55
Muscle spindle: pathway?
In parallel with muscle fibers. Muscle stretch --\> intrafusal stretch --\> stimulates Ia afferent --\> stimulate alpha motor neuron --\> reflex muscle (extrafusal) contraction
56
Spindle muscle control: the Gamma loop
CNS stimulates gamma motor neuron --\> contracts intrafusal fiber --\> increased sensitivity of reflex arc
57
Clinical reflexes and their respective nerve roots: Achilles? Patella? Biceps? Triceps?
Achilles = S1 nerve root; Patella = L4 nerve root; Biceps = C5 nerve root; Triceps = C7 nerve root
\*Note that they count up in order: S1,2 L3,4 C5,6 C7,8
58
Babinski sign
Dorsiflexion of the big toe and fanning of other toes; sign of UMN lesion, but normal reflex in 1st year of life.
59
Primitive reflexes. When do they disappear or reappear? What are they (6)
Normally disappear within 1st year of life. May reemerge following frontal lobe lesion.
Include: Moro reflex (3-6 months), rooting reflex (most immediate survival), suckling reflex, palmar and plantar reflexes (1-2 months), Babinski reflex (1 year), Galant reflex.
60
Moro reflex
"hang on for life" reflex - abduct/extend limbs when startled, and then draw together; 3-6 months disappear
61
Rooting reflex
Movement of head toward one side if cheek or mouth is stroked (nipple seeking)
62
Sucking reflex
Sucking response when roof of mouth is touched
63
Palmar and palantar reflexes
Curling of fingers/toes if palms of hands/feet are stroked (1-2 months)
64
Galant reflex
Stroking along one side of the spine while newborn is in ventral suspension (face down) causes lateral flexion of lower body toward stimulated side.
65
Cranial nerves that lie medially at the brainstem
III, VI, XII Remember: 3 (x2) = 6 (x2) = 12
66
Which cranial nerve arises dorsally and emerges ventrally?
CN IV
67
Dorsal brainstem structures: Pineal gland
Melatonin secretion, circadian rhythms.
68
Dorsal brainstem structures: superior colliculi
Conjugate vertical gaze center. ("you have your eyes above your ears, and the superior colliculus (visual) is above the inferior colliculus (auditory).")
69
Dorsal brainstem structures: inferior colliculi
Auditory ("you have your eyes above your ears, and the superior colliculus (visual) is above the inferior colliculus (auditory).")
70
Parinaud syndrome
Paralysis of conjugate verticle gaze due to lesion in superior colliculi (e.g., pinealoma)
71
Cranial nerves: Olfactory (CN I) function? type? mnemonic?
Smell (only CN w/o thalamic relay to cortex) S ensory; "S ome" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
72
Which cranial nerve is this? (Function, type, mnemonic) Smell (only CN w/o thalamic relay to cortex) S ensory; "S ome" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Olfactory (CN I)
73
Cranial nerves: Optic (CN II) function? type? mnemonic?
Sight. S ensory; "S ay" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
74
Which cranial nerve is this? (Function, type, mnemonic) Sight. S ensory; "S ay" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Optic (CN II)
75
Cranial nerves: Oculomotor (CN III) function? type? mnemonic?
Eye movement (SR, IR, MR, IO), pupillary constriction, accommodation, eyelid opening (levator palpebrae) M otor; "M oney" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
76
Which cranial nerve is this? (Function, type, mnemonic) Eye movement (SR, IR, MR, IO), pupillary constriction, accommodation, eyelid opening (levator palpebrae) M otor; "M oney" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Oculomotor (CN III)
77
Cranial nerves: Trochlear (CN IV) function? type? mnemonic?
Eye movement (SO) M otor; "M oney" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
78
Which cranial nerve is this? (Function, type, mnemonic) Eye movement (SO) M otor; "M oney" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Trochlear (CN IV)
79
Cranial nerves: Trigeminal (CN V) function? type? mnemonic?
Mastication, facial sensation. B oth, "B ut" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
80
Which cranial nerve is this? (Function, type, mnemonic) Mastication, facial sensation.
B oth, "B ut" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."] Trigeminal (CN V)
81
Cranial nerves: Abducens (CN VI) function? type? mnemonic?
Eye movement (LR) M otor; "M y" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
82
Which cranial nerve is this? (Function, type, mnemonic) Eye movement (LR) M otor; "M y" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Abducens (CN VI)
83
Cranial nerves: Facial (CN VII) function? type? mnemonic?
Facial movement, taste from anterior 2/3rds of tongue, lacrimation, salivation (submandibular and sublingual glands), eyelid closing (orbicularis oculi), stapedius muscle in ear B oth; "B rother" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
84
Which cranial nerve is this? (Function, type, mnemonic) Facial movement, taste from anterior 2/3rds of tongue, lacrimation, salivation (submandibular and sublingual glands), eyelid closing (orbicularis oculi), stapedius muscle in ear B oth; "B rother" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Facial (CN VII)
85
Cranial nerves: Vestibulocochlear (CN VIII) function? type? mnemonic?
Hearing, balance. S ensory; "S ays" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
86
Which cranial nerve is this? (Function, type, mnemonic) Hearing, balance. S ensory; "S ays" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Vestibulocochlear (CN VIII)
87
Cranial nerves: Glossopharyngeal (CN IX) function? type? mnemonic?
Taste from posterior 1/3rd of tongue, swallowing, salivation (parotid gland), monitoring carotid body and sinus chemo- and baroreceptors, and stylopharyngeus (elevates pharynx, larynx) B oth; "B ig" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
88
Which cranial nerve is this? (Function, type, mnemonic) Taste from posterior 1/3rd of tongue, swallowing, salivation (parotid gland), monitoring carotid body and sinus chemo- and baroreceptors, and stylopharyngeus (elevates pharynx, larynx) B oth; "B ig" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Glossopharyngeal (CN IX)
89
Cranial nerves: Vagus (CN X) function? type? mnemonic?
Taste from epiglottic region, swallowing, palate elevation, talking, coughing, thoracoabdominal viscera, monitoring aortic arch chemo- and baroreceptors. B oth; "B rains" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
90
Which cranial nerve is this? (Function, type, mnemonic) Taste from epiglottic region, swallowing, palate elevation, talking, coughing, thoracoabdominal viscera, monitoring aortic arch chemo- and baroreceptors. B oth; "B rains" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Vagus (CN X)
91
Cranial nerves: Accessory (CN XI) function? type? mnemonic?
Head turning, shoulder shrugging M otor; "M atter" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
92
Which cranial nerve is this? (Function, type, mnemonic) Head turning, shoulder shrugging M otor; "M atter" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Accessory (CN XI)
93
Cranial nerves: Hypoglossal (CN XII) function? type? mnemonic?
Tongue movement M otor; "M ore" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
94
Which cranial nerve is this? (Function, type, mnemonic) Tongue movement M otor; "M ore" [Mnemonic for type of information carried by CN's: "Some Say Marry Money, But My Brother Says Big Brains Matter Most."]
Hypoglossal (CN XII)
95
Cranial nerve nuclei: Where are they located, generally?
Located in tegmentum portion of brainstem (btw dorsal and ventral portions). Lateral nuclei = sensory M edial nuclei = M otor
96
Cranial nerve nuclei located in the midbrain
Nuclei of CN III and IV
97
Cranial nerve nuclei located in the pons
Nuclei of CN V (mid pons), VI, VII, and VIII (lower pons)
98
Cranial nerve nuclei located in the medulla
Nuclei of CN IX, X, XI, and XII
99
Which cranial nerves are involved in corneal reflex and lacrimation? (both afferent and efferent)
Corneal reflex: Afferent (V1 ophthalmic - levator palpebrae); Efferent: VII (temporal branch; orbicularis oculi)
Lacrimation: V1 (loss of reflex does not preclude emotional tears); Efferent: VII
100
Afferent = V-1 Efferent = VII What CN reflex is this?
Corneal OR Lacrimation (use the same nerves)
101
CN reflexes: Jaw jerk Afferent? Efferent?
Afferent = V-3 (sensory - muscle spindle from masseter) Efferent = V-3 (motor - masseter)
102
Afferent = V-3 (sensory) Efferent = V-3 (motor) What CN reflex is this?
Jaw jerk
103
CN reflexes: Pupillary Afferent? Efferent?
Afferent = II Efferent = III
104
Afferent = II Efferent = III What CN reflex is this?
Pupillary
105
CN reflexes: Gag Afferent? Efferent?
Afferent = IX Efferent = IX and X
106
Afferent = IX Efferent = IX and X What CN reflex is this?
Gag
107
Vagal nuclei: Nucleus Solitarious
Visceral S ensory information (e.g., taste, baroreceptors, gut distension) CN VII, IX, X ("S olitarius = viS ceral S ensory")
108
Vagal nuclei: Nucleus ambiguous
M otor innervation of pharynx, larynx, and upper esophagus (e.g., swallowing, palate elevation) CN's IX, X, XI ("aM biguous = M otor")
109
Vagal nuclei: Dorsal motor nucleus
Sends autonomic (parasympathetic) fibers to heart, lungs, and upper GI.
110
Cranial nerve and vessel pathways: What exits via the cribiform plate?
CN I
111
Cranial nerve and vessel pathways: What exits via the middle cranial fossa?
CN II-VI, thru the sphenoid bone: 1.) Optic canal : CN II, ophthalmic artery, central retinal vein 2.) S uperior orbital fissure : CN III, IV, V-1, VI, ophthalmic vein 3.) Foramen R otundum : CN V-2 4.) Foramen O vale : CN V-3 5.) Foramen spinosum : middle meningeal artery ("Divisions of CN-V exit owing to S tanding R oom O nly")
112
Cranial nerve and vessel pathways: What exits via the Posterior cranial fossa?
CN VII-XII, thru the temporal and occipital bone: 1.) Internal auditory meatus : CN VII, VIII 2.) Jugular foramen : CN IX, X, XI, jugular vein 3.) Hypoglossal canal : CN XII 4.) Foramen magnum : Spinal roots of CN XI, brain stem, vertebral arteries
113
What/where is the cavernous sinus? What is the route of blood thru it?
A collection of venous sinuses on either side of the pituitary. Blood from eye and superficial cortex -\> Cavernous sinus -\>Internal jugular vein
114
What nerves pass through the cavernous sinus?
CN II, IV, V-1, V-2, VI, and postganglionic sympathetic fibers en route to the orbit all pass thru the cavernous sinus. Only CN VI is "free-floating". Cavernous portion of internal carotid artery is also here.
115
What is cavernous sinus syndrome?
Nerves that control extraocular muscles (plus V-1 and V-2) pass thru the cavernous sinus. Therefore, cavernous sinus syndrome (e.g., due to mass effect): ophthalmoplegia, ophthalmic and maxillary sensory loss.
116
CN XII lesion (LMN) What is the defect?
Tongue deviates toward the side of the lesion ("lick your wounds") due to weakened tongue muscles on the affected side
117
CN V motor lesion. What is the defect?
Jaw deviates toward the side of lesion due to unopposed force from opposite pterygoid muscle
118
CN X lesion. What is the defect?
Uvula deviates away from side of lesion. weak side collapses and uvula points away.
119
CN XI lesion. What is the defect?
Weakness turning head to contralateral side of lesion (SCM). Shoulder droop on side of lesion (trapezius).
120
Facial lesions: UMN lesion
Lesion of motor cortex or connection btw cortex and facial nucleus. Contralateral paralysis of lower face only, since upper face recives bilateral UMN innervation.
121
Facial lesions: LMN lesion
Ipsilateral paralysis of upper and lower face.
122
Facial lesions: Bell's palsy
Complete destruction of the facial nucleus itself or its branchial efferent fibers (facial nerve proper). Peripheral ipsilateral facial paralysis w/ inability to close eye on involved side. Can occur idiopathically; gradual recovery in most cases.
123
In what dz's/disorders is Bell's palsy seen as a complication?
A IDS L yme dz H erpes simplex S arcoidosis T umors D iabetes ("**AL** exander gra**H** am **Bell** with **STD**")
124
KLM sounds (kuh, la, mi). Which nerves are involved?
Say it aloud. "Kuh-kuh-kuh" tests palate elevation (CN X - vagus) "La-la-la" tests tongue (CN XII - hypoglossal) "Mi-mi-mi" tests lips (CN VII - facial) ("It would be a K aL aM ity to lose CN X, XII, and VII")
125
Muscles of mastication
3 Muscles close jaw: M asseter, teM poralis, and M edial pterygoid ("M 's M unch") 1 Muscle opens jaw: Lateral pterygoid ("M's Munch. Lateral Lowers" -- [when speaking of pterygoids with respect to jaw motion]) "It takes more muscle to keep your mouth shut." All above are innervated by the trigeminal nerve (V-3)
126
Muscles with glossus
All muscles with the root glossus in their names (except palatoglossus, innervated by vagus nerve) are innervated by the hypoglossal nerve. Palat : vagus nerve Glossus : hypoglossal nerve
127
Muscles with palat
All muscles with the root palat in their names (except tensor veli palatini , innervated by mandibular branch of CN V) are innervated by vagus nerve. Palat : vagus nerve (except TENS or, who was too TENSE )
128
Inner ear as a "series of tubes"
A series of tubes in the temporal bone (bony labrynth) filled with perilymph (Na+ rich, similar to ECF) that includes cochlea, vestibule, and semicircular canals. W/in the bony labyrinth is a 2nd series of tubes (membranous labyrinth) filled w/ endolymph (K+ rich, similar to ICF) that includes cochlear duct (w/in the cochlea), utricle and saccule (w/in the vestibule), and semicircular canals. \*peri = think outside of the cell (Na+), vs. Endo = think inside the cell (K+)
129
Where is the endolymph (of the inner ear) made?
Made by the stria vascularis.
130
What do the utricle and saccule contain? What do they detect?
Contain maculae - detect linear acceleration.
131
What do the semicircular canals contain? What do they detect?
Contain A mpullae, detect A ngular acceleration.
132
Hair cells (of the inner ear): Where are they? What do they do?
Located w/in the organ of Corti. Are the sensory elements in both vestibular apparatus (spatial orientation) and cochlea (hearing).
133
How can you remember where frequencies are sensed along the cochlear membrane?
The cochlear membrane = scuba flipper: narrow/stiff at the base (high frequency), and wide/flexible at the apex (low frequency).
134
Conductive hearing loss
Abnormal rinne test (bone\>air); Weber test localizes to affected ear.
135
Sensorineural hearing loss
Normal Rinne test (air\>bone); Weber localizes to normal ear.
136
Hearing loss in the elderly
High frequency --\< low frequency
137
What are the muscles that make up the iris? What receptors do they have, and what are their effects?
Dilator/radial muscle (alpha1 --\> myd riasis [pupillary d ilation]) Sphincter/circular/constrictor muscle (M3 --\> miosis [pupillary constriction])
138
Where are the ciliary muscles? What receptors do they have, and what effect?
M3 --\> accomodation
139
Where is aqueous humor made? Where is it reabsorbed? [give the whole pathway]
Aqueous humor is made by ciliary process -\> Travels past lens to posterior Chamber -\> Anterior chamber -\> Trabecular meshwork (absorbs aqueous humor -\> Canal of Schlemm (collects aqueous humor from trabecular meshwork)
140
Glaucoma (general pathogenesis)
Impaired flow of aqueous humor -\> Increased intraocular pressure -\> Optic disk atrophy w/ cupping
141
Open angle glaucoma
Obstructed outflow (e.g., canal of Schlemm); associated w/ myopia, advanced age, African-American race. More common, "silent," painless.
142
Closed angle glaucoma
Obstruction of flow btw iris, lens --\> pressure builds up behind iris. Very painful, impaired vision, rock-hard eye, frontal headache. An opthalmologic emergency. Do NOT give epinephrine.
143
Cataract
Painless, bilateral opacification of lens, leading to decrease in vision; glare from headlights. Risk factors: age, smoking, EtOH, sunlight, diabetes (sorbital), trauma, congenital infection, classic galactosemia, galactokinase deficiency, long term steroid use
144
Papilledema
Increased intracranial pressure --\> elevated optic disk with blurred margins, bigger blind spot (can be seen in hydrocephalus)
145
Innervation of the extraocular muscles?
CN VI innervates the L ateral R ectus CN IV innervates the S uperior O blique CN III innervates the R est Thus, the "chemical formula": LR6 SO4 R3
146
What are the 3 actions of the superior oblique?
It abducts, intorts, and depresses.
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CN III damage
Eye looks down and out; ptosis, pupillary dilation, loss of accomodation.
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CN IV damage
Diplopia w/ defective downward gaze
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CN VI damage
Medially directed eye.
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Testing extraocular muscles
To test fxn of each muscle, have the pt look in the following directions: [\*note that the oblique muscles are tested by looking medially and opposite to what you would expect from "superior" and "inferior"] "IOU : to test I nferior O blique, have pt look U p."
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Strabismus vs. Amblyopia
Strabismus is misalignment of eyes. Multiple etiologies. Amblyopia is a reduction of vision from disuse in critical period. May be secondary to strabismus, deprivation, unequal refractive errors.
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What controls pupillary constriction (miosis)
P upillary sphincter muscle (aka circular muscle), P arasympathetic innervation. Innervation -- CN III from Edinger-Westphal nucleus --\> ciliary ganglion.
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What controls pupillary D ilation (myD riasis)?
RaD ial muscle (aka pupillary D ilator muscle), sympathetic. Innervation -- T1 preganglionic sympathetic --\> superior cervical ganglion --\> postganglionic sympathetic --\> long ciliary nerve.
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Pupillary light reflex
Light in either retina sends a signal via CN II to pretectal nuclei (dashed lines, below) in midbrain that activate bilateral Edinger-Westphal nuclei; pupils constrict bilaterally (consensual reflex). Result: illumination of 1 eye results in bilateral pupillary constriction.
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Marcus Gunn pupil
Afferent pupillary defect (e.g., due to optic nerve damage or retinal detachment). Decreased bilateral pupillary constriction when light is shone in affected eye.
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CN III in cross-section
Output to ocular muscles - affected primarily by vascular disease (e.g. diabetes: glucose -\> sorbitol) due to decreased diffusion to interior. Symptoms: ptosis, "down and out" gaze.
Parasympathetic output - affected 1st by compression (e.g. PCOM berry aneurysm, uncal herniation); use pupillary light reflex in assessment, "blown pupil".
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Retinal detachment
Separation of neurosensory layer of retina from pigment epithelium -\> Degeneration of photoreceptors -\> Vision loss May be secondary to trauma, diabetes; flurries
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Age-related macular degeneration (ARMD)
Degeneration of macula (central area of retina). Causes loss of central vision (scotomas). "Dry"/atrophic ARMD is slow, due to fat deposits, and causes gradual decrease in vision "Wet" ARMD is rapid, due to neovascularization.
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Visual field defects: Where is the lesion?
```
#1, below
Right anopia
```
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Visual field defects: Where is the lesion?
#2, below. Bitemporal hemianopia (pituitary denoma, prolactinoma; mass in sella turcica)
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Visual field defects: Where is the lesion?
#3, below; Left homonymous hemianopia.
162
Visual field defects: Where is the lesion?
#4, below. Left upper quadrantic anopia. Right temporal lesion, MCA
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Visual field defects: Where is the lesion?
#5, below; Left lower quadrantic anopia (right parietal lesion, MCA)
164
Visual field defects: Where is the lesion?
#6, below; Left hemianopia w/ macular sparing -\> bilateral projection to occiput
165
Visual field defects: Where is the lesion?
#7, below;Central scotoma (macular degeneration)
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Internuclear ophthalmoplegia (MLF syndrome)
Lesion in the medial longitudinal fasciculus (MLF) --\> medial rectus palsy on attempted lateral gaze. Nystagmus in abducting eye. Convergence normal. Syndrome is seen in many pts w/ multiple sclerosis ("M LF = M S")
When looking left, the left nucleus of CN VI fires, which contracts the lateral rectus and stimulates the contralateral (right) nucleus of CN III via the right MLF to contract the right medial rectus.
167
Renitis. What is it?
Retinal necrosis + edema leading to atrophic scar (seen in Aids patients with CMV)
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What is iritis?
Systemic inflammation (e.g. Reiter's [reactive arthritis])
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How do eye muscles change for near vision?
Ciliary muscle contracts (zonular fibers relax -\> lens relax -\> more convex)
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How do eye muscles change to allow for distant vision?
Ciliary muscle relaxes -\> lens flattens
171
How does aging affect the eye?
Sclerosis and decreased elasticity causes presbyopia (no near vision) due to change in lens shape?
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Retinal artery occlusion. Etiology and Presentation.
Acute, painless monocular loss of vision; pale retina and cherry-red macula (has its own blood supply from choroid artery). Major cause of central retinal artery occlusion is atheroma or embolism.
173
Where is Meyer's loop?
Loops around inferior horn of lateral ventricle; inferior retina
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Where is dorsal optic radiation?
Takes shortest path through internal capsule; superior retina
