Neurology Flashcards
1
Q
The notochord induces the overlying ___ to differentiate into ___ and form ___.
A
Ectoderm; neuroectoderm; neural plate
2
Q
The neural plate gives rise to the ___ and ___.
A
Neural tube; neural crest cells
3
Q
List the three primary vesicles of the developing brain.
A
- Forebrain (prosencephalon)
- Midbrain (mesencephalon)
- Hindbrain (rhombencephalon)
4
Q
List the five secondary vesicles of the developing brain and their origins.
A
- Telencephalon (forebrain)
- Diencephalon (forebrain)
- Mesencephalon (midbrain)
- Metencephalon (hindbrain)
- Myelencephalon (hindbrain)
5
Q
What are the adult derivatives of the telencephalon?
A
Cerebral hemispheres and lateral ventricles
6
Q
What are the adult derivatives of the diencephalon?
A
Thalamus, hypothalamus, and third ventricle
7
Q
What are the adult derivatives of the mesencephalon?
A
Midbrain and aqueduct
8
Q
What are the adult derivatives of the metencephalon?
A
Pons and cerebellum, upper part of the fourth ventricle
9
Q
What are the adult derivatives of the myelencephalon?
A
Medulla, lower part of the 4th ventricle
10
Q
Explain motor innervation to the tongue.
A
CN X to palatoglossus (elevates posterior tongue during swallowing)
CN XII to hyoglossus (retracts and depresses tongue), genioglossus (protrudes tongue), and styloglossus (draws sides of tongue upward to create a trough for swallowing)
11
Q
Where is RER not present in neurons and thus not seen on Nissle staining?
A
RER is not present in the axon
12
Q
What is Wallerian degeneration?
A
Caused by injury to an axon; degeneration of axon distal to the site of injury and axonal retraction proximally; allows for potential regeneration of the axon if in the PNS
Involves chromatolysis
13
Q
Function of astrocytes?
A
Physical support, repair, extracellular K+ buffer, removal of excess neurotransmitter, component of BBB, glycogen fuel reserve buffer; reactive gliosis in response to neural injury
14
Q
Astrocyte staining marker?
A
GFAP
15
Q
What happens to HIV-infected microglia?
A
They fuse to form multinucleated giant cells in the CNS
16
Q
Function of myelin?
A
Increases conduction velocity of signals transmitted down axons; wraps and insulates axons
17
Q
How does myelin increase conduction velocity?
A
Decreases membrane capacitance by decreasing stored charge and increases resistance by decreasing charge leakage; increases the space constant and decreases the time constant to increase the conduction velocity
18
Q
What synthesizes myelin?
A
Oligodendrocytes in the CNS, Schwann cells in the PNS
19
Q
How do oligodendrocytes appear histologically?
A
Fried egg appearance
20
Q
In what neural pathologies are oligodendrocytes injured?
A
MS, PML, leukodystrophies
21
Q
List the 5 sensory receptors in the nervous system.
A
- Free nerve endings
- Meissner corpuscles
- Pacinian corpuscles
- Merkel discs
- Ruffini corpuscles
22
Q
Which type of sensory neuron fiber is found in free nerve endings?
A
C - slow, unmyelinated fibers
A(delta) - fast, myelinated fibers
23
Q
Which type of sensory neuron fiber is found in Meissner corpuscles?
A
Large, myelinated fibers; adapt quickly
24
Q
Which type of sensory neuron fiber is found in Pacinian corpuscles?
A
Large, myelinated fibers; adapt quickly
25
Which type of sensory neuron fiber is found in Merkel discs?
Large, myelinated fibers; adapt slowly
26
Which type of sensory neuron fiber is found in Ruffini corpuscles?
Dendritic endings with capsule; adapt slowly
27
Where are free nerve endings located and what senses do they carry?
All skin, epidermis, some viscera; pain and temperature
28
Where are Meissner corpuscles located and what senses do they carry?
Glabrous (hairless) skin; dynamic, fine/light touch, position sense
29
Where are Pacinian corpuscles located and what senses do they carry?
Deeps kin layers, ligaments, joints; vibration and pressure
30
Where are Merkel discs located and what senses do they carry?
Finger tips, superficial skin (basal layer of the epidermis); pressure, deep static touch (eg, shapes, edges), position sense
31
Where are Ruffini corpuscles located and what senses do they carry?
Finger tips, joints; pressure, slippage of objects along surface of skin, joint angle change
32
Describe the structure of peripheral nerves.
1. Endoneurium - inner layer that invests single nerve fiber layers
2. Perineurium - surrounds a fascicle of nerve fibers; blood-nerve permeability barrier
3. Epineurium - dense connective tissue that surrounds the entire nerve (fascicles and blood vessels)
33
What is chromatolysis?
The reaction of neuronal cell bodies to axonal injury; changes reflect increased protein synthesis in an effort to repair the damaged axon
34
Describe the appearance of chromatolysis on H&E.
Round cellular swelling, displacement of the nucleus to the periphery, dispersion of Nissl substance throughout the cytoplasm
35
List the 5 major neurotransmitters affected in diseases like anxiety, depression, schizophrenia, Alzheimer disease, Huntington disease, Parkinson disease.
1. ACh
2. Dopamine
3. GABA
4. NE
5. 5-HT
36
Where is ACh synthesized?
Basal nucleus of Meynert
37
Where is dopamine synthesized?
Ventral tegmentum, SNc
38
Where is GABA synthesized?
Nucleus accumbens
39
Where is NE synthesized?
Locus ceruleus
40
Where is 5-HT synthesized?
Raphe nucleus
41
What neurotransmitters change in anxiety?
Decreased GABA, 5-HT
| Increased NE
42
What neurotransmitters change in depression?
Decreased dopamine, NE, 5-HT
43
What neurotransmitters change in schizophrenia?
Increased dopamine
44
What neurotransmitters change in Huntington disease?
Decreased ACh, GABA
| Increased dopamine
45
What neurotransmitters change in Parkinson disease?
Increased ACh
| Decreased dopamine, 5-HT
46
Which diseases involve affected ACh?
Decreased - Alzheimer disease and Huntington disease
| Increased - Parkinson disease
47
Which diseases involve affected dopamine?
Decreased - depression, Parkinson disease
| Increased - schizophrenia, Huntington disease
48
What diseases involve affected GABA?
Decreased - anxiety, Huntington disease
49
What diseases involve affected NE?
Increased - anxiety
| Decreased - depression
50
What diseases involve affected 5-HT?
Decreased - anxiety, depression, Parkinson disease
51
Compare the embryologic origin of the meningeal layers.
Dura - mesoderm
| Arachnoid and pia - neural crest
52
Where does CSF flow?
Subarachnoid space (between arcahnoid and pia)
53
What structures form the BBB?
1. Tight junctions (transmembrane claudins and occludins that associate with actin filaments) between nonfenestrated capillary endothelial cells
2. Basement membrane
3. Astrocyte foot processes
54
What can cross the BBB?
1. Glucose and amino acids - carrier-mediated transport (slow)
2. Nonpolar/lipid-soluble substances - diffusion (rapid)
55
Which specialized brain structures have fenestrated capillaries and no BBB?
1. Area postrema - medulla (vomiting after chemo)
2. OVLT, aka organum vasculosum lamina terminalis (osmotic sensing)
3. Neurohypophysis (allows neurosecretory products to enter circulation)
56
What causes vasogenic edema?
Destruction of endothelial cell tight junctions by infarction and/or neoplasm
57
What is the purpose of the hypothalmus?
```
Maintain homeostasis via regulation of:
Thirst and water balance
Adenohypophysis (AP)
Neurohypophysis (PP)
Hunger
ANS
Temperature
Sexual urges
TAN HATS
```
58
List the 6 major components of the hypothalamus.
1. Lateral area
2. Ventromedial area
3. Anterior hypothalamus
4. Posterior hypothalamus
5. Suprachiasmatic nucleus
6. Supraoptic and paraventricular nuclei
59
What does the lateral area control?
Hunger (destruction -> anorexia, failure to thrive in infants)
Stimulated by ghrelin, inhibited by leptin
"If you zap your lateral area, you shrink laterally"
60
What does the ventromedial area control?
Satiety (destruction -> hyperphagia)
Stimulated by leptin
"If you zap your ventromedial area, you grow ventrally and medially"
61
What does the anterior hypothalamus control?
Cooling, parasympathetic
| "Anterior nucleus = cooling -> A/C"
62
What does the posterior hypothalamus control?
Heating, sympathetic
63
What does the suprachiasmatic nucleus control?
Circadian rhythm
| "You need sleep to be charismatic"
64
What do the suproptic and paraventricular nuclei control?
Synthesis of ADH and oxytocin
65
Circadian rhythm controls nocturnal release of what 4 hormones?
ACTH, Prl, melatonin, NE (Suprachiasmatic nucleus -> NE -> pineal gland -> melatonin)
66
What drugs are associated with decreased REM sleep and delta wave sleep?
Alcohol, benzodiazepines, barbiturates (NE also decreases REM sleep)
67
List the sleep stages in order and the % of total sleep time in young adults.
1. Awake (eyes open)
2. Awake (eyes closed)
3. Non-REM sleep (N1 - 5%, N2 - 45%, N3 - 25%)
4. REM sleep (25%)
68
Describe the sleep stage and the associated EEG waveform - awake (eyes open and eyes closed).
Alert, active mental concentration
Eyes open - beta (highest frequency, lowest amplitude)
Eyes closed - alpha
69
Describe the sleep stage and the associated EEG waveform - N1.
Light sleep; theta
70
Describe the sleep stage and the associated EEG waveform - N2.
Deeper sleep; when bruxism (teeth grinding) occurs; sleep spindles and K complexes
71
Describe the sleep stage and the associated EEG waveform - N3.
Deepest non-REM sleep (slow-wave sleep); when sleepwalking, night terrors, and bedwetting occur; delta (lowest frequency, highest amplitude)
72
Describe the sleep stage and the associated EEG waveform - REM.
Loss of motor tone, increased brain O2 use, increased and variable pulse and BP lead to increased ACh; when dreaming, nightmares, and penile/clitoral tumescence occur; may serve memory processing function
Depression increases total REM sleep but decreases REM latency
Extraocular movements duo to activity of PPRF
Occurs every 90 minutes, and duration increases throughout the night
Beta
73
List the EEG waveforms in order from awake to REM sleep.
```
Beta
Alpha
Theta
Sleep spindles and K complexes
Delta
Beta
```
At night, BATS Drink Blood
74
What is the role of the thalamus?
Major relay for all ascending sensory information except olfaction
75
List the nuclei of the thalamus.
1. Ventral postero-lateral nucleus
2. Ventral postero-medial nucleus
3. Lateral geniculate nucleus
4. Medial geniculate nucleus
5. Ventral lateral nucleus
76
What is the input, information carried, and destination of the VPL nucleus?
Input - STT and dorsal columns/medial lemniscus
Senses - Vibration, Pain, Pressure, Proprioception, Light touch, temperature (VPPPL)
Destination - primary somatosensory cortex
77
What is the input, information carried, and destination of the VPM nucleus?
Input - trigeminal and gustatory pathway
Senses - face sensation, taste
Destination - primary somatosensory cortex
"Makeup goes on the face"
78
What is the input, information carried, and destination of the lateral geniculate nucleus?
Input - CN II
Senses - vision
Destination - calcarine sulcus
Lateral = Light
79
What is the input, information carried, and destination of the medial geniculate nucleus?
Input - superior olive and inferior colliculus of tectum
Senses - hearing
Destination - auditory cortex of temporal lobe
Medial = Music
80
What is the input, information carried, and destination of the the ventral lateral nucleus?
Input - basal ganglia, cerebellum
Senses - motor
Destination - motor cortex
81
What are the components of the limbic system?
Hippocampus, mammillary bodies, anterior thalamic nuclei, cingulate gyrus, entorhinal cortex (collection of neural structures involved in emotion, long-term memory, olfaction, behavior modulation, ANS function) -> Feeding, Fleeing, Fighting, Feeling, Sex
82
List the 4 dopaminergic pathways.
1. Mesocortical
2. Mesolimbic
3. Nigrostriatal
4. Tuberoinfundibular
83
What happens with decreased activity of the mesocortical pathway?
Negative symptoms (eg, anergic, apathy, lack of spontaneity)
84
What happens with increased activity of the mesolimbic pathway?
Positive symptoms (eg, delusions, hallucinations)
85
What happens with decreased activity of the nigrostriatal pathway?
Extrapyramidal symptoms (eg, dystonia, akathisia, parkinsonism, tardive dyskinesia)
86
What is the major dopaminergic pathway in the brain?
Nigrostriatal pathway
87
What happens with decreased activity of the tuberoinfundibular pathway?
Increased prolactin -> decreased libido, sexual dysfunction, galactorrhea, gynecomastia (in men)
88
What is the function of the cerebellum?
Modulates movement; aids in coordination and balance
89
What are the inputs to the cerebellum?
Contralateral cortex via the middle cerebellar peduncle
| Ipsilateral proprioceptive information via the inferior cerebellar peduncle from the spinal cord
90
What are the outputs of the cerebellum?
Cerebellar cortex -> Purkinje cells -> deep nuclei of the cerebellum -> contralateral cortex via superior cerebellar peduncle (inhibitory)
91
List the deep nuclei of the cerebellum for lateral to medial.
Dentate, Emboliform, Globose, Fastigial
| "Don't Eat Greasy Foods"
92
What happens with lateral lesions of the cerebellum?
Affect voluntary movement of the extremities (limbs); when injured, propensity to fall toward injured (ipsilateral side)
93
What happens with medial lesions of the cerebellum?
Affects midline structures (vermal cortex, fastigial nuclei) and/or the flocculonodular lobe -> truncal ataxia (wide-based cerebellar gait), nystagmus, head tilting; generally result in bilateral motor deficits affecting axial and proximal limb musculature
94
What is the purpose of the basal ganglia?
Important in voluntary movements and making postural adjustments
95
What are the general inputs and outputs of the basal ganglia?
Cortical input, provides negative feedback output to the cortex
96
List the components of the basal ganglia.
1. Caudate
2. Putamen
3. Globus pallidus
4. Subthalamic nucleus
5. Substantia nigra
97
Describe the excitatory pathway of the basal ganglia.
Cortical inputs stimulate the striatum, stimulating the release of GABA, which inhibits GABA release from the GPi, disinhibiting the thalamus via the GPi (increase in motion)
98
Describe the inhibitory pathway of the basal ganglia.
Cortical inputs stimulate the striatum, releasing GABA that disinhibits the subthalamic nucleus via Gpe inhibition, and STN stimulates GPi to inhibtit the thalamus (decreases motion)
99
Describe the role of dopamine in the pathways of the basal ganglia.
Dopamine binds to D1, stimulating the excitatory pathway, and to D2, inhibiting the inhibitory pathway - both increase motion
100
Compare the striatum and the lentiform nucleus.
```
Striatum = putamen (motor) + caudate (cognitive)
Lentiform = putamen + globus pallidus
```
101
List the important regions of the frontal lobe.
1. Prefrontal association area
2. Frontal eye field
3. Broca area
4. Premotor cortex
5. Primary mortor cortex
102
What separates the frontal lobe from the parietal lobe?
Central sulcus
103
List the important regions of the parietal lobe.
1. Primary somatosensory cortex
| 2. Somatosensory assocation cortex
104
What separates the frontal lobe from the temporal lobe?
Sylvian fissure
105
List the important regions of the temporal lobe.
1. Limbic association area
2. Primary auditory cortex
3. Wernicke area
106
List the important regions of the occipital lobe.
1. Primary visual cortex
107
What is the primary modulator of cerebral perfusion?
PCO2 (PO2 modulates perfusion only in severe hypoxia - <50 mmHg)
108
What causes decreased cerebral perfusion pressure (CPP)?
Decreased blood pressure or increased ICP
109
Explain therapeutic hyperventilation.
Decreases PCO2 -> vasoconstriction -> decreased cerebral blood flow -> decreased ICP (can treat acute cerebral edema unresponsive to other interventions)
110
CPP = ?
CPP = MAP - ICP
111
If CPP = 0, what happens?
There is no cerebral perfusion -> brain death
112
List the three cerebral arteries and their cortical distribution.
1. Anterior cerebral artery (anteromedial surface)
2. Middle cerebral artery (lateral surface)
3. Posterior cerebral artery (posterior and inferior surfaces)
113
What are the watershed zones of the cerebral arteries?
Between anterior/middle and posterior/middle
114
What happens with damage (severe hypotension) to the watershed zones of the cerebral arteries?
Upper leg/upper arm weakness, defects in higher-order visual processing
115
The dural venous sinuses are large venous channels that run through the dura. They drain blood from ___ and receive ___ from arachnoid granulations. They empty into the ___.
Cerebral veins; CSF; Internal jugular vein
116
What are the components of the ventricular system?
Lateral ventricles -> 3rd ventricle -> 4th ventricle -> subarachnoid space
117
What connects the ventricles?
Lateral ventricle empties via the R and L interventricular foramina of Monro -> 3rd ventricle
3rd ventricle ->4th ventricle via aqueduct of Sylvius
4th ventricle -> subarachnoid space via foramina of Luschka (lateral) and Foramen of Magendie (medial)
118
Which CN arises dorsally and immediately decussates?
CN IV
119
Describe the arrangement of the CN and the brainstem from the ventral view.
I, II, III, IV - above the pons
V, VI, VII, VIII - in the pons
IX, X, XI, XII - in the medulla
III, IV, VI, XII - medial
120
Describe the arrangement of the brainstem from the dorsal view (cerebellum removed).
```
Inferior to superior:
Medulla
Middle cerebellar peduncles
4th ventricle
Superior cerebellar peduncles
Inferior colliculi
Superior colliculi
Pineal body
```
121
What is the role of the pineal gland?
Secrete melatonin, circadian rhythm
122
What is the purpose of the superior and inferior colliculi?
Superior - conjugate vertical gaze center
| Inferior auditory
123
Where are the cranial nerve nuclei located (generally0?
Tegmentum portion of the brain stem - etween the dorsal and ventral portions
124
Describe the locations of the CN nuclei in the brain stem.
Midbrain - III, IV
Pons - V, VI, VII, VIII
Medulla - IX, X, XII
Spinal cord - XI
Lateral nuclei - sensory (alar plate)
Medial nuclei - motor (basal plate)
125
Where does CN I exit/enter the skull?
Cribriform plate
126
Where does CN II exit/enter the skull?
Optic canal (with the phthalmic artery
127
Where do CN III, IV, V1, and VI exit the skull?
Superior orbital fissure
128
Where does CN V2 exit the skull?
Foramen rotundum
129
Where does CN V3 exit the skull?
Foramen ovale
130
Where does CN V exit the skull?
V1 - superior orbital fissure
V2 - foramen rotundum
V3 - foramen ovale
(Standing Room Only)
131
What exits the skull via the foramen spinosum?
Middle meningeal artery
132
Where do CN VII and VIII exit the skull?
Internal auditory meatus
133
What exits the skull via the jugular foramen?
CN IX, X, XI, and the jugular vein
134
Where does CN XII exit/enter the skull?
Hypoglossal canal
135
What exits the skull via the foramen magnum?
Brainstem
Spinal root of CN XI
Vertebral arteries
136
What is the name and function of CN I?
Olfactory nerve
| Smell
137
What is the only cranial nerve without a thalamic relay to the cortex?
Olfactory
138
What is the name and function of CN II?
Optic
| Sight
139
What is the name and function of CN III?
```
Oculomotor
Eye movements (SR, IR, MR, IO), pupillary constriction (sphincter pupillae: EW nucleus, muscarinic receptors), accommodation, eyelid opening (levator palpebrae)
```
140
What is the name and function of CN IV?
```
Trochlear
Eye movements (SO)
```
141
What is the name and function of CN V?
Trigeminal
Mastication, facial sensation (ophthalmic, maxillary, mandibular division), somatosensation from the anterior 2/3 of the tongue
142
What is the name and function of CN VI?
```
Abducens
Eye movements (LR)
```
143
What is the name and function of CN VII?
Facial
Facial movement, taste from the anterior 2/3 of the tongue, lacrimation, salivation (submandibular and sublingual glands), eyelid closing (orbicularis oculi), auditory volume modulation (stapedius)
144
What is the name and function of CN VIII
Vestibulochochlear
| Hearing, balance
145
What is the name and function of CN IX?
Glossopharyngeal
Taste and sensation from posterior 1/3 of tongue, swallowing, salivation (parotid gland), monitoring the carotid body and sinus chemo- and baroreceptors, and elevation of pharynx/larynx (stylopharyngeus)
146
What is the name and function of CN X?
Vagus
Taste from the supraglottic region, swallowing, soft palate elevation, midline uvula, taking, cough reflex, parasympathetics to the thoracoabdominal viscera, monitoring the aortic arch chemo- and baroreceptors
147
What is the name and function of CN XI?
Accessory
| Head turning, shoulder shrugging (SCM, trapezius)
148
What is the name and function of CN XII?
Hypoglossal
| Tongue movement
149
List the type of innervation carried by each of the cranial nerves.
```
I - Sensory
II - Sensory
III- Motor
IV - MOtor
V - Both
VI - Motor
VII - Both
VIII - Sensory
IX - Both
X - Both
XI - Motor
XII - Motor
"Some Say Marry Money But My Brother Says Big Brains Matter Most"
```
