Neuro Pre-midterm Flashcards
(313 cards)
1
Q
Above the midbrain, define the terms: Rostral, Caudal, Dorsal & Ventral
A
Anterior/Rostral; Posterior/Caudal
2
Q
Below the midbrain, define the terms: Rostral, Caudal, Dorsal & Ventral
A
Anterior/Ventral; Posterior/Dorsal
3
Q
What is the official boundary between the CNS & PNS?
A
Redlich-Obersteiner’s Zone
4
Q
Where can nerves regenerate: CNS or PNS?
A
PNS
5
Q
What are the 5 major components of the brain?
A
- Telencephelon
- Diencephelon
- Mesencephalon
- Metencephalon
- Myencephalon
(Myelon = S/C)
6
Q
Telencephalon
A
Lateral ventricles, cerebrun, cortex (gray + white matter)
7
Q
Differentiate between gray/white matter in the brain and spinal cord.
A
Brain: White inside
S/C: Gray inside
8
Q
Diencephalon
A
3rd ventricle, thalamus & hypothalamus
9
Q
Metencephalon
A
Midbrain
10
Q
Metencephalon
A
Pons + Cerebellum
11
Q
Myencephalon
A
Medulla
12
Q
What are the 6 cerebral lobes?
A
Frontal, Temporal, Parietal, Occipital, Limbic & Insular
13
Q
What are the 6 layers of the cerebral cortex (outside in)?
A
- Molecular layer
- External granular layer
- External pyramidal layer (small pyr)
- Internal granular layer
- Internal pyramidal (ganglionic or large pyr)
- Multiform/Polymorphus
14
Q
Where are Betz cells found?
A
Layer 4 of the cerebrum / lumbar spinal motor neurons
15
Q
Thalamic input arrives at what level of the cerebrum?
A
4
16
Q
Corticospinal/bulbar output leaves from which cerebrum layer?
A
5
17
Q
The efferent layers of the cerebrum are:
A
3 & 5 (2 and 6)
18
Q
The cerebellum is responsible for
A
Motor function; posture, balance, smooth muscle coordination
19
Q
The pons has 2 parts:
A
Dorsal: sensory (respiratory, taste, sleep/wake)
Ventral: motor
20
Q
The 3 types of white matter:
A
Projection
Commisural
Association
21
Q
What are basal ganglia?
A
Groups of neurons deep within white matter associated with initiation/organization of movement
22
Q
What is the difference between T1 & T2?
A
T1 differentiates between white/gray matter
T2 shows white water (CSF) – ventricles are white
23
Q
Differentiate between epidural, subdural, and sub-arachnoid hemorrhage.
A
Epidural: Football
Subdural: Crescent
Sub-arachnoid: Follows granulations
24
Q
Bone Morphogenic Protein (BMP)
A
Suppresses neural differentiation; promotes epidermal tissue growth
25
Homeobox (HOX) genes
60 AA's that recognize and bind specific DNA sequences; coordinate expression of genes (A-P axis)
26
Retinoic acid
Source: Hensen's node
| * Activates transcription of HOX genes; established gradient along length of embryo
27
Sonic hedgehog protein
Synthesized by notochord and floor plate; induces floor plate cells and motoneurons of the ventral spinal cord
28
EMX & OTX mutations
EMX: Schizencephaly
OTX: Epilepsy
29
Where do you find younger neurons on radial glia?
Younger neurons migrate further than older ones
30
What are radial glial cells?
Contact ventral and pial surface; neurons move along the scaffolding
31
Describe Cajal-Retzius/Reeler gene
Reelin tells neurons to stop migrating!
32
What types of cells provide an exception to the principle that radial glial cells provide migration/guidance? Name the condition.
GnRh cells
| Kallmann's Syndrome: no smell / no sexual development
33
What is leukemia inhibit factor?
Peptide released by the heart which can change phenotype; underscoring the principle that a neuron's environment influences its commitment to function
34
Describe the role of PMP-22
This protein myelinates peripheral neurons
| * Protein normally broken down in absence of axons
35
What is Laminin?
Promotes axonal outgrowth; found surrounding neurons and satellite cells
36
What is netrin?
A diffusable substance released by the floor plate; attracts axons to the developing spinal cord
37
What are the primary divisions of the primitive CNS?
Prosencephalon; Mesencephalon; Rhombencephalon
38
What is the objective of a graded potential?
Drive potential towards the axon hillock to threshold at which point an action potential can be generated
39
Rods/Cones convert photons into receptor potential?
Rods
Night vision: increase cGMP, Na-channels open
Day vision: decreased cGMP, hyperpolarization (decreased glutamate)
40
Olfactory epithelium are bipolar sensory neurons. How do they function with respect to G proteins?
Increase cAMP with increasing odor stimulus
41
What is spasticity?
Increased muscle tone; hyperexcited muscles with increase in voltage-gated Na-channels open
42
How do you differentiate between the functions of neurons and glia?
Neurons: action potentials
Glia: Ca-dependent signaling with gap junctions; no action potentials
43
What are the 3 layers of the cerebellum?
Molecular, Purkinje, Granular
44
Bipolar neurons
Interneurons
45
Pseudounipolar neurons
CNS PNS
46
What is special about herpes, polio, rabies, paravirus with respect to neurons?
They use retrograde transport up axons to reach the soma
47
What are the different types of glial cells?
Micro: macrophages
Macro: astrocytes, oligodendrocytes, ependymal, radial glia, perivascular astrocyes, tanycytes (PNS: satellite, Schwann, enteric)
48
T/F Neurons regenerate in the CNS
False
49
Who re-myelinates in the PNS?
Schwann cells
50
What is Wallerian degeneration?
Following injury, degeneration distral to the axonal damage
51
What is the difference between retrograde and anterograde transport?
Retrograde: Dyenin -- axon--> soma
Anterograde: Kinesin -- soma --> axon
52
What are the 3 elements of cytoskeleton important for transport in a neuron?
1. Microfilaments
2. Intermediate filaments
3. Microtubules
53
What are the 4 classes of sensory receptors?
Mechano, thermo, chemo, photo - receptors
54
What are the 6 sensory systems?
Somatosensory, visual, vestibular, auditory, olfactory, gustatory
55
What are the 4 attributes that characterize a sensory stimulus?
Modality
Intensity
Duration
Location
56
Differentiate between slow and rapidly adapting receptors.
Slow -- good for physiologic montioring; constantly depolarized
Fast -- more sensitive to change
57
All neurons of the somatosensory system are..
Pseudounipolar neurons
58
The 5 modalities of somatosensory system:
1. Touch, Proprioception, Vibration
| 2. Pain, Temperature
59
What are the 4 somatosensory fibers?
Fastest: 1-alpha, 2-beta, 3-delta, 4-C :Slowest
60
C2
Back of head
61
C6
Thumb
62
C7
Middle finger
63
C8
Little finger
64
T4
Nipple line
65
T10
Umbilicus
66
L1
groin
67
L5
Big toe
68
S1
Little toe
69
What are the 2 somatosensory pathways?
1. Dorsal-column medical leminiscus touch/vibration/proprioception
2. Anterolateral pain/temp
70
Describe the routes to the brain for the somatosensory pathways
1. D-C/M-L -- medial to lateral (leg, trunk, arm)
Leg goes to gracile fasiculus; arm goes to cuneate fasiculus in medulla
2. Anterolateral (spinothalamic); dorsal horn --> cross anterior white commissure --> ALS fiber tract to thalamus (Leg-lateral, arm-medial)
71
Describe Lissauer's tract
Collaterals of Anterolateral system can ascend 1 or 2 levels in the dorsolateral fasiculus
72
Describe the sensory aspect of Brown-Sequard Syndrome
See notes
73
What is syringomyelia?
Pathologic enlargement of central canal of S/C
* Interrupts pain/temperature fibers that cross the anterior white commissure
Bilateral pain/temperature loss @ and below lesion;
Note Lissaeur contribution
74
What is shingles/herpes zoster?
Following an attack of the chickenpox, the herpes virus may become latent in dorsal root ganglion cells (or trigeminal ganglion cells). Reactivation of the virus produces painful skin irritations in the dermatomal area innervated by the related ganglion
75
Describe the 3 neuron chain for DRG & trigeminal ganglia touch, proprioception, and vibration
See notes
76
What are the 3 features of the primary somatosensory cortex?
1. Somatotopic map
2. Organization in columns
3. Input to layer 4
77
With respect to 2 point discrimination, a higher resolution means...
Greater density of mechanoreceptors, small receptive fields, larger cortical area involved +/- lateral inhibition
78
How do we examine touch, vibration, proprioception? Basic and Complex
Touch w/ pain; vibration, proprioception - finger
79
What is the first somatosensation lost with peripheral neuropathies?
Vibration
80
What is stereogenesis and graphesthesia?
Stereo: place a stereo in hand, ask what it is
Graph: draw a number or letter in the palm
81
What is tapes dorsalis?
Destruction of DRG (loss of touch, proprioception) in syphillis
82
What is characteristic of phantom limbs?
Rearrangement of cortical neurons
83
Describe the 2 types of pain
1. Nociceptive (stimulus driven)
| 2. Neuropathic (more complex/ abberent processing)
84
Describe the spinal and trigeminal pain pathways (First, second, third order neurons and tracts)
First order neuron: substantia gelatinosa of dorsal horn
Second order neuron: crosses midline (ant white commissure) and ascends through ALS tract to synapse at VPL in thalamus
Third order neuron: travels through posterior I/C and corona radiata to synapse in somatosensory cortex
85
Differentiate between hyperalgesia and allodynia
Hyperalgesia: enhanced senstion of pain in area around injury
Allodynia: Previously painful stimuli become painful
86
What is the optic fundus?
Back portion of the interior of the eyeball
87
Describe the layout of the eyeball
Cornea (sclera), a/p chambers, iris, lens; retina is innermost layer, after sclera and choriod
88
Differentiate between constriction and dilation (pupil)
Constriction - para - contract ciliary muscle, relax suspensory ligaments
89
Differentiate between myopia, hyperopia & emmetropia
Myopia: near sightedness; requires biconcave lens; eye is too long/refractive power is too strong
90
What is the condition called for loss of refractive capability with age?
Presbyopia
91
The lens has a higher/lower refractive power for near vision?
Higher
92
What part of the eye is responsible for the greatest refractive power?
Cornea
93
Light generally causes what type of reaction in photoreceptors?
Hyperpolarization (activation of cGMP phsphodiesterase)
94
Describe the wavelength of Red, Green, Blue
Red: longest wavelength
Blue: shortest wavelength
95
What are the 5 cell types in the retina?
1. Photoreceptors
2. Bipolar
3. Ganglion
(Horizontal & amacrine)
96
Describe the difference between ON and OFF cells.
ON cells stimulated by light, leads to depolarization, release of INHIBITORY glutamate (metabotropic)
OFF cells stimulated by darkness, leads to depolarization, release of EXCITATORY glutamate (ionotropic)
97
Which vitamin is responsible for night blindness?
Vitamin A
98
What is the objective of horizontal cells?
Inhibits the pathway in the adjacent retinal cells
99
Retinitis pigmentosa
Characterized by night blindness and tunnel vision; degeneration of rods
100
Differentiate between the 2 major types of color-blindness.
R-G most common (X-recessive)
Protanopia: L cone (red cone absent)
Deuteranopia: M cone (green cone absent)
101
Rods have more/less convergence than cones
More
102
Which is the active version of the visual pigment retinal: cis or trans
Trans
103
T/F monochromatic blue light depolarizes all 3 types of cones
True
104
Who is more sensitive to light: rods or cones
Rods
105
What is the posterior boundary of the frontal lobe?
Central sulcus
106
How do you differentiate between a subarachnoid hemorrhage and an epidural hemorrhage?
SA: meningeal irritation
Epi: lucid interval
107
What are the 2 types of brain herniation?
Uncal: upper
Tonsillar: lower (bottom of pons)
108
What blood vessels supply the medulla?
AICA, PICA, ASA
109
What blood vessels supplies the pons?
Basilar artery (pontine branches)
110
What blood vessels supply the midbrain?
Posterior cerebral and superior cerebellar
| * Oculomotor nucleus
111
Where is the EW nucleus located?
Midbrain
112
What is aphasia?
Inability to speak
113
What is anisocoria?
Pupils different sizes
114
What reflex is associated with the flocculonodular lobe of the cerebellum?
Vestibulooccular -- focus eye on a point while moving head
115
Biceps reflex
C5, 6
116
Triceps reflex
C7, 8
117
Abdo reflex (above/below umbilicus)
8,9,10; 10,11,12
118
Knee jerk reflex
L 2, 3, 4
119
Ankle reflex
S1
120
Define obtunded
Lower than full mental capacity
121
Where are aneurysms more likely to occur?
At junctions of vessels (Lg --> Small)
122
What is the chief symptom of a SA hemorrhage?
Thunderclap headache
123
Where is there no choriod plexus?
A/P lateral ventricle; cerebral aqueduct
124
Differentiate between the gracile and cuneate nuclei
Gracile: medial; legs
Cuneate: lateral; arms
125
Where is the lamina terminalis?
Anterior to the 3rd ventricle
126
What is located at the inferior horn of the lateral ventricle?
Hippocampus
127
Where is area posterma and with what is it associated?
Medulla; nausea/vomiting
128
Which artery supplies the acoustic meatus?
Labyrinth (branch of AICA)
129
The lenticulostriate artery is a branch of...
MCA
130
Which vessels are closest to the optic chiasm?
Posterior cerebral; ACA/MCA
131
Where is the OVLT?
Lamina terminalis
132
Where would an uncal herniation occur?
Tentorial notch; between brain stem and tentorial cerebelli
133
What is the embryologic significance of the lamina terminalis?
It is where the rostral neuropore closes
134
Differentiate between Broca's and Wernicke's aphasia.
Broca's: problem with actual motor movement of speech
| Wernicke's: Gibberish
135
The frontal lobe has X sulci and Y gyri
```
2 sulci
3 gyri (superior, middle, inferior)
```
136
The parietal lobe has X gyri
2; superior & inferior
137
The temporal lobe is similar to the X lobe because of the same number of gyri/sulci
Frontal
138
Where is the olfactory cortex?
Near uncus (near the parahippocampal gyrus)
139
Who is faster: ionotropic or metabotropic?
Ionotropic
140
What is the difference between small molecule and neuropeptide NT's?
Small molecule: catecholamines, glutamate, etc.
Neuropeptide: endorphorins, substance P
Neuropeptides synthesized in RER/Golgi
141
Differentiate between quantum, quantum content, quantum size
Quantum: a single vesicle
Quantum size: how many NT/vesicle
Quantum content: # of quanta released per vesicle
142
Benzodiazapines work at which recetpors?
GABA
143
Differentiate between first and second pain.
First pain: A-delta
| Second pain: C fibers
144
Through what structure do fibers in the ALS cross over?
Anterior white commissure
145
What substances and NT’s activate nociceptors?
Bradykinin, histamine, K
146
Opiods mimic the action of what NT or substance
Enkephalin
147
Serotonergic neurons come from... (descending pain)
Periaquductal grey, nucleus raphe magnus
148
Descending pain fibers travel through...
Lateral/Anterior funiculi
149
With respect to the gate theory, large myelinated fibers carrying touch activate inhibitory neurons where...
Dorsal horn of S/C (First/Second neurons)
150
Which structure is mainly responsible for the refractive power of the eye? Cornea or lens
Cornea
151
During far vision is the ciliary muscle relaxed or contracted?
Relaxed [ciliary muscle is a circular muscle that surrounds the lens. When it is relaxed the diameter of the circular structure is large resulting in the zonule fibers tightening & flattening the disk. This minimizes the lens’ refractive power.]
152
What is presbyopia?
Loss of lens elasticity
153
What color does the optic disk have normally and when there is increased ICP?
Pink normally & white when ICP is increased
154
These types of cells are the persistent forms of radial glia [aid neuron migration during development] in the retina:
Muller cells
155
OFF center ganglionic cells receive excitatory/inhibitory input from off center bipolar cells
Excitatory input from OFF center bipolar cells
156
Type of receptor on ON & OFF center bipolar cells
ON: glutamate - metabotropic
OFF: AMPA (ionotropic)
157
Glutamate Ca2+ channel receptor
NMDA
158
What part of thalamus receives input from retinal ganglion cells?
Lateral geniculate nucleus
159
What is the name of the chromophore in the visual pigment molecule?
Retinal
160
Are able to detect low intensity light: Rods or Cones
Rods
161
Fingers have the highest density of which of the following when compared to the rest of the body?
Merkle's discs
162
What remains in tact with tabes dorsalis?
Pain & temperature (Lose touch, vibration, proprioception)
163
What is vasogenic edema?
Occurs due to the failure of tight junctions and astrocyte processes which normally maintain an adequate blood-brain barrier.
164
What is cytotoxic edema?
In this type of edema the BBB remains intact. This edema is due to failure of ATP-dependent ion transport (sodium and calcium pumps). As a result there is cellular retention of sodium and water
165
MS shows the following elevated in CSF
IgG
166
What are the chief molecules lower in CSF vs. plasma
K, Ca, protein, glucose, pH
167
When is the measurement of ICP by lumbar puncture inaccurate?
Ventricular obstruction
168
What type of cell allows communication between extracellular fluid in the CNS & CSF?
Group 2 ependymal
169
What are the three functions of astrocytes?
Buffering, lactate --> neurons, remove NT's
170
What type of cell makes up the choroid plexuses?
Group I ependymal
171
What type of cell lines the spinal canal & extrachoroidal portions of the ventricles?
Group 2 ependymal
172
Cerebral perfusion pressure is equal to
MAP - ICP
173
Dandy-Walker syndrome (congenital hydrocephalus) is due to
Failure of Luschka/Magendie to develop
174
Features Horner's syndrome
(lesion of sympa) Anhydrosis, ptosis, miosis, and enopthalamos
175
Which sympathetic activities are governed by M receptors?
Eccrine sweat, renal vasculature, smooth muscle of skeletal muscle
176
Which neurotransmitters are amines?
ACh, serotonin, dopamine, E/NE, histamine
177
Which neurotransmitter can be broken down by COMTs, MAO's
COMT: NE/Epi/Dopamine
MAO: NE/Epi/Dopamine/Serotonin
178
What 2 neurotransmitters are released by nociceptors in the substantia gelatinosa?
Glutamate, Substance P
179
Which neurotransmitters are amines?
ACh, serotonin, dopamine, E/NE, histamine
180
Which neurotransmitter can be broken down by COMTs, MAO's
COMT: NE/Epi/Dopamine
MAO: NE/Epi/Dopamine/Serotonin
181
What 2 neurotransmitters are released by nociceptors in the substantia gelatinosa?
Glutamate, Substance P
182
Which neurotransmitter antagonist is often used to treat psychosis?
Dopamine
183
Tricyclics prevent the uptake of which 2 neurotransmitters?
NE, Serotonin
184
Which dopaminergic receptor types are excitatory?
D1/D5
185
What rate limiting enzyme in the formation for catecholamines?
DOPA dc
186
Glutamate Ca2+ channel
NMDA
187
Metabotropic receptor of primary inhibitory NT in CNS
GABA-b
188
Activity enhanced by benzodiazepines
GABA-a
189
What parasympathetic system receptor agonist is used in the treatment of glaucoma that works by facilitating fluid drainage in the eye through the canal of Schlemm?
Pilocarpine
190
Which neurotransmitter is synthesized in vesicles?
NE
191
There are 2 neurotransmitters that are not rapidly removed from synaptic cleft
ACh, NO
192
Who can block glutamate channels?
Mg
193
Which is the inhibitory neurotransmitter of the S/C?
Glycine
194
Why does hypocalcemia result in tetany?
Since extracellular Ca2+ helps screen negative charges fixed to the outer surface when it is reduced there are more negative charges distributed along the outer membrane and the Voltage across the membrane is reduced. The excitable cell is more easily excited because the new threshold is closer to the resting potential.
195
Aminoglycoside antibiotics
Calcium channel blockers
196
Bungaratoxin
Nm anagonist
197
Omega-conotoxin
Ca channel blocker
198
Tetanus
Prevents the inhibitory reflex -- results in hyperflexia
199
Which of the options associates with syntaxin during docking?
Synaptobrevin
200
Which neurotransmitters are located in small dense core vesicles?
NE
201
Which of the options are v-Snares?
Syntaptobrevin, synaptotagmin
202
Which of the options are t-Snares?
Neurexin, Syntaxin
203
Which of the options is responsible for trafficking and targeting vesicles to the exocytosis site?
RAB
204
Which of the options associates with neurexin during docking?
Synaptotagmin
205
Which of the options is thought to be involved in the formation of the fusion pore?
Synaptophysin
206
Which of the options is involved in the retrieval of cell membrane to reform vesicles?
Clathrin
207
The filling of vesicles with neurotransmitters is generally dependant on establishing a higher concentration of what ion within the vesicle?
H+
208
By what transport system is choline brought back into the synaptic terminal?
Na-cotransport
209
Binds irreversibly to actin in cholinergic nerve endings blocking ACh release?
Beta-bungaratoxin
210
Irreversible antagonist of nAChR’s on muscles
Alpha-bungaratoxin
211
Plant alkaloid that blocks glycine receptors in the CNS?
Strychine
212
Bacterial toxin that enters inhibitory interneurons acting on motor neurons and prevents the normal release inhibitory transmitter by breaking down synaptobrevin?
Tetanus
213
Bacterial toxin that causes demyelination of motor and sensory neurons?
Diptheria
214
Binds to the receptor for the neuropeptide mu-enkephalin activating them?
Morphine
215
For what type of neurotransmitter is diffusion out of the synaptic cleft a SIGNIFICANT mechanism of removal?
Neuropeptides
216
Increasing the length constant result in … quicker/slower decrease in voltage/amplitude as distance increases
Slower
217
Which neurotransmitter is released by excitatory neurons onto motor neurons?
Glutamate
218
Which neurotransmitter is released by motor neurons onto skeletal muscle fibers?
Glycine
219
What is the function of muscle spindles?
Measure muscle length when stretch gated channels open allowing cations [mostly Na+] into the cell depolarizing it
220
In multipolar neurons graded potentials are summed at the ___________________ & when their summation reaches the _________________ an action potential is fired.
Axon hillock; threshold
221
In sensory neurons graded potentials are summed near the ___________________ & when their summation reaches the _________________ an action potential is fired.
Sensory nerve ending; threshold
222
Light shined to the Left superior quadrant ends up in the ________________ ______________ of the retina.
Right inferior
223
The primary visual cortex receives its major blood supply from...
Calcarine branches of posterior cerebral a.
224
LGN has 6 layers. What's the difference?
2/6: M cells (magnocellular/depth + motion)
| 4/6: P cells (parvocellular/form + color)
225
Optic nerve lesion (visual defect & cause)
Optic nerve Monocular blindness Optic neuritis
226
Optic chiasm lesion (visual defect & cause)
Optic chiasm Bitemporal hemianopia Pituitary tumor
227
Optic tract lesion (visual defect & cause)
Optic tract Homonymous hemianopia Temporal tumor
228
Temporal/Parietal radiation (visual defect & cause)
Temporal radiation Homonymous superior quadrant anopia Temporal/occipital tumor
Parietal radiation Homonymous inferior quadrant anopia Parietal/occipital tumor
229
Visual cortex lesion (visual defect & cause)
Visual cortex Homonymous hemianopia Posterior cerebral a. occlusion
230
Describe color agnosia (achromtopsia)
Inability to distinguish color (cortical color blindness)
231
Describe the two columnar organizations of V1, the primary visual cortex
Ocular dominance (Ipsilateral & Contralateral); Orientation (vertical/horizontal)
232
Describe the difference between Magnocellular and Parvocellular neurons.
Magno: depth/motion (dorsal/parietal); Parvo: color/form (ventral/temporal tract)
233
Where in the visual cortex does the macula innervate?
Close to the occipital pole (also gets MCA blood supply; macula sparing)
234
Define gaze, palsy, paresis
Gaze: Coordination of head/eye movements to look into one direction
Palsy/Paralysis: loss of motor function
Paresis: slight/incomplete paralysis
235
Differentiate between the 3 major types of eye movement
Conjugate: Saccadic-normal eye movement from point to point, Vestiboccular, Optokinetic
Non-conjugate: Cross-eyed (convergence/divergence)
Dysconjugate: fucked up eyes
236
Which are the two extraocular eye muscles not controlled by oculomotor nerve?
SO4 (trochlear)
| LR6 (abducens)
237
Where in the cerebrum is the initiation of saccadic eye movements?
Frontal eye field
238
What is the significance of the parieto-occipital eye field?
This is where the dorsal/parietal pathway (motion/3D) ends up; optokinetic eye movement
239
Describe the cortical pathway of saccadic eye movement
Frontal eye field --> pons (cross midline) PPRF --> CN6 activation; CN6 --> cross midline MLF tract --> CN3 activation
240
What is MLF and PPRF?
MLF -- in the midbrain; involved in saccadic eye movments; PPRF -- in the pons; receive signal from the frontal eye field
241
What is diplopia?
Visual fields of both eyes do not match
242
Internuclear opalmoplegia
MLF lesion; Prevents adduction of the one eye on the side of the lesion during attempted lateral gaze
243
PPRF lesion
Conjugate gaze towards the side of the lesion is impaired (left gaze palsy, left lesion)
244
One and one-half syndrome
MLF + PPRF lesions
245
Endolymph has a high concentration of this ion.
K+
246
Depolarization of hair cells is generated by...
Influx of K+ ions
247
Aside from the ion that causes depolarization, resulting inward current of _____ causes release of excitatory transmitter at the base of hair cells.
Ca++
248
Otolith/Semicircular canals; Linear/Angular acceleration
Otolith: Linear
Semicircular: Angular
249
What are the 2 otolith organs?
Utricle and saccule
250
The center of the utricle and saccule is called the...
Striola
251
What is the anatomical difference between the utricle and saccule's hair cells with respect to the striola?
Kinocilum is TOWARDS the striola in utricle; away is saccule
This allows for activation and inactivation simultneously
252
What is embedded in the otolith membrane?
Calcium carbonate crystals
253
Rotation of the head to the left causes excitation/inhibition of semicircular canal labyrinth of left
Excitation; causes the endolymph to move to the right
254
Conjugate eye movements are in the same direction/opposite to head movement.
Opposite
255
T/F Visual input is required for conjugate eye movements in the VOR reflex.
False -- can occur in complete darkness
256
What is nystagmus?
Rhythmically alternating movements of the eye
257
Meniere's disease
Abnormalities of endolymph circulation can lead to significant dilation of endolymph compartments and degeneration of hair cells. The disease affects the vestibular and auditory system and is characterized by recurrent sudden vertigo, tinnitus, sensorineural hearing loss
258
Describe the effect of ETOH on the vestibular system
The spinning bed phenomenon
* interactions of blood alcohol with the endolymph which can cause convection endolymph flows within the semicircular canals
259
What are possible consequences of long-term antibiotics?
Destruction of vestibular hair cells
260
What are the 2 terms for each eye of a bilateral pupillary response?
Direct + Consensual
261
How does the pupil know to constrict if you are only telling the LGN that there is light?
Some fibers innervate the EW pre-tectal nucleus of the midbrain; travel with CN3 & ciliary ganglion --> short ciliary nerves
262
Describe the corneal reflex
Nocioceptors in the cornea --> pons via V1 --> descend through pons/medulla (pain pathway) to CN5 spinal nucleus --> facial nuclei in lower pons
263
Describe the CN involved in the opening and closing of the eyes
Open: 3 (lev palpebrae superioris) & sympa (tarsal)
Close: 7 (orbicularis oculi)
264
Differentiate between conduction and sensorineural hearing loss.
Conduction: outer/middle ear
Sensorineural: cochlea/auditory n.
265
What are the two factors that contribute to sound amplification in the middle ear.
1. Oval window = small; big force
| 2. Ossicles act like a lever system
266
The scala vestibuli and scala tympani are continuous through the ...
Helicotremma
267
What forms the lateral wall of the scala media & what type of ions does it secrete?
Stria vasucalris (actively secretes K ions)
268
Differentiate between where on the basilar membrane high vs. low frequencies are best detected.
High: Oval window (narrow/stiff)
Low: Helicotremma (wide/floppy)
269
What is the name of the concept : where the place (or location) of a nerve cell encodes for a specific stimulus feature?
Place code
270
Except for 3 different types of lesions, there are no lesions that produce unilateral hearing loss. What are they?
1. Damage to ear
2. Damage to CN8
3. Damage to cochlear nuclei
271
A lesion of the inferior colliculus will disrupt one's ability to...
Disrupt ability to localize sound
272
Where is the primary auditory cortex?
Transverse temporal gyrus of Heschl
273
Differentiate between the location of high/low frequencies in the tonotopically organized primary auditory cortex.
Low frequency: lateral (rostral)
| High frequency: medial (caudal)
274
What is the difference between EE & EI columns in the primary auditory cortex?
EE: both ears, summation
EI: one ear, suppression
275
Where in the brain is the "coincidence detection" pathway?
Superior olive (Medial SO)
276
Two sound signals approach the ears. A larger/smaller EPSP is recorded for a sound that reaches both ears simultaneously.
Larger
277
Localization of sound is performed in the __________ region of the brainstem. The two methods of coincidence detection and interaural amplitude differences are located __________________.
Superior olive
* Coincidence detection: medial
* Interaural amplitidue differences (most effective for high frequencies): lateral -- includes inhibitory neurons
278
What is Weber's Test?
Lateralization; tuning fork to the mid-scalp/forehead
*Reaches inner ear directly through bone
Normal Hear in both ears
Conductive loss Sound lateralizes to ipsilateral side (side of disease)
Sensorineural Sound lateralizes to the contralateral side (side of normal hearing)
279
What is Rinne's Test?
Tests bone/air conduction (air >> bone because of amplification in middle ear)
1. Tuning fork to the mastoid
2. Tuning fork to air (air should be better than bone in normal subjects)
* Conductive hearing loss: bone >> air (decreased sound perception during air)
280
Otosklerosis
Causes conductive hearing loss
* Gradual replacement of normal bone of bony labyrinth and stapes by lamellar new bone. Leads to fusion of stapes with borders of oval window.
281
Vestibular Schwannoma
Causes Sensorinueral hearing loss
Acoustic neuroma; benign tumor of Schwann cells of CN8; compresses the vestibulocochlear nerve of IAM; hearing loss + tinnitus
282
Cochlear implants
Microphone, electronic processor, and array of stimulating electrodes can help restore hearing; adjacent fibers attached to inner hair cells may still be in tact
* Surgical implantation into the cochlea
283
How often are new olfactory sensory cells made?
Every 60 days
284
What is the vomeronasal organ?
Chemoreceptive for pheromones; one study demonstrated that menstrual cycles can be manipulated based on armpit odorless pheromones
285
What is special about the olfactory system?
Information reaches temporal/limbic lobes before relaying in the thalamus
286
What is the mode of communication of the olfactory system?
cAMP
287
Describe the pathway for taste. Does this pathway cross the midline?
Does not cross midline
* Pseudounipolar --> Geniculate/Inferior ganglion --> pontomedullary junction --> Solitary nucleus --> Ipsilateral VPM of thalamus --> primary gustatory cortex (insular lobe/posterior central gyrus)
288
Differentiate cranial nerves of taste.
Ant 2/3: CN7
Pos 1/3: CN9
Way back: CN10
289
Describe the 4 major taste buds and the signaling mechanism.
Salty: Na+ in
Sour: H+ w/ Na or H+ blocks K
Sweet: cAMP
Bitter: PLC--> IP3 --> Ca++
290
Where on the tongue are the taste buds?
Anterior: salty, sour, sweet
Posterior: sour/bitter
291
What is Wallenburg's syndrome?
Wallenberg (Lateral Medullary) Syndrome may arise from occlusion of the posterior inferior cerebellar artery (PICA).
292
What might cause olfactory hallucinations?
Partial epileptic seizures around the region of uncus
293
Differentiate between hypogeusea, ageusea, hyposmia, anosmia.
Hypogeusea: decreased taste (oral pathology)
Ageusea: loss of taste (Wallenburg)
Hyposmia: decreased smell (more common than taste)
Anosmia: Meningioma (loss of smell)
294
4 main types of EEG waves
Beta: highest frequency, frontal active, thinking open eyes
Alpha: awake, closed eyes, occipital
Theta: drowsy
Delta: deep sleep/coma
295
How do you differentiate between different types of EEG waves?
L vs. R
Spikes = bad
Slow waves = bad
296
Differentiate between primary and secondary epilepsy
Primary: genetic
Secondary: symptomatic, partial, focal
297
Small, reactive pupils
Cortex, or diencephalon
298
Fixed, dilated pupils
Pre-tectal, midbbrain
299
Pinpoint pupils
Pons
300
One pupil fixed and dilated
Uncal, fixed, dilated
301
GCS
E: 4 -- spontaneous, verbal, pain, X
V: 5 -- oriented, confused, inapprop, incompre, X
M: 6 -- comands, loc pain, w/draw pain, flex, extend, X
302
Ventral tegmental system
Reward pathway--nucleus accumbens
303
D2 antagonist
Haldol / anti-psychotic
304
What is the relationship b/t Parkinson's and psychosis
Treatment for one can lead to the other
305
Sedatives
ETOH, benzo, barb, opiods
306
Hallucinogens
Ketamine, LSD, angel dust
307
Stimulants
Amphetamine, cocaine, ecstacy, nicotine
308
Withdrawal from a sedative causes...
Stimulation
309
Treating withdrawal
Anti-adrenergic: CNS -- clonidine
Anti-convulsant: diazapam
Anti-psychotic: haldol
310
T/F Opiod detox is life threatening
False; can be treated with methadone
311
Differentiate between transmission and burst EEG
Transmission: normal, high frequency
Burst: deep sleep, coma, low frequency
312
3 Treatments for epilepsy
Block excitation by blocking Na+ channels (phenytoin, carbamazepine)
Increase inhibition: GABA-ergic, benzo's, barbs
Anti-convulsant: Levetiracetam (Keppra)
313
3 characteristics of grand mal seizure
Tonic-grunt/cry, clonic-jerky movements, post-tictal
