Anatomy/Neuropathology Flashcards
1
Q
What is the path of the direct light reflex?
A
retinal ganglion cells → optic nerve → optic tract → brachium of superior colliculus → pretectal area → posterior commissure → both oculomotor nuclei → Edinger–Westphal subnucleus → ciliary ganglion → pupillary sphincter muscle
2
Q
What is the function of RiMLF? Location? input and output?
A
located above the oculomotor nucleus in the MLF at the junction of the midbrain/diencephalon. It is the main center for vertical eye movements (especially downward). It reacts to vestibular and visual stimulation:
Input: superior vestibular nucleus and PPRF.
Output: mainly to the oculomotor complex (inferior rectus portion).
3
Q
What are the functions of the periaqueductal gray?
A
Central analgesia, vocalization, control of reproductive behavior, aggressive behavior, and upward gaze
4
Q
Location, input, and output of the interpeduncular nucleus:
A
Located just dorsal to the interpeduncular fossa.
Input: habenular nucleus via fasciculus retroflexus.
Output: diffuse cholinergic fibers to various parts of the CNS.
5
Q
What is the organization of the crus cerebri?
A
Crus cerebri:
Corticospinal and corticobulbar tracts: middle two-thirds of the crus cerebri (lower extremities located laterally).
Corticopontine tracts: extreme medial and lateral ends of crus cerebri (frontopontine medially and parieto-temporo-occipitopontine located laterally).
6
Q
what are the outputs of the pontine reticular formation?
A
Pontine reticular formation:
Sends crossed reticulospinal fibers (muscle tone) → spinal cord LMN.
Fibers to central tegmental tract (wakefulness) → thalamic intralaminar nuclei (for arousal).
7
Q
Function of the locus ceruleus and location:
A
Locus ceruleus:
Pigmented (melanin).
Neurotransmitter: NE (primarily excitatory but some receptors inhibitory) with wide projections.
Function: controls cortical activation and paradoxical (rapid eye movement) sleep.
located in the pons
8
Q
What is secreted by the Raphe nucleus and its location? inhibitory or excitatory? effect?
A
Raphe nucleus in the lower pons/medulla—inhibits via 5-HT; mostly influences the thalamus (for sleep and restful functions), but also the cortex (for sleep) and spinal cord (to decrease pain).
9
Q
What are the projections of the substantia nigra and their effects?
A
projects inhibitory fibers that release DA to the caudate and putamen. However, note that DA is excitatory in the hypothalamus and limbic system
10
Q
What is secreted by Gigantocellular layer of the reticular activating system and what are the projections? Where is it located?
A
in the pons/midbrain—stimulates via ACh; neurons relay one branch to the cortex and one branch to the reticulospinal tract.
11
Q
What are the skin receptors (6), their location, sensation, receptive field, and type of fiber used?
A
12
Q
What is ferrugination?
A
occurs when dead neurons become encrusted with Fe2+ and Ca2+ salts
13
Q
What is central chromatolysis? What are the cellular changes? Syndromes when this phenomenom is seen?
A
occurs after an injury to an axon near the cell body. The Nissl substance disappears, the nucleus becomes eccentric, and the cell body enlarges. It is seen in the anterior horn cells with anterior nerve root compression and Guillain–Barré syndrome. The cells may progress to death or recover.
14
Q
What are the three most common bugs that cause meningitis? What is the common age groups and respective treatment?
A
three most common causes of meningitis (i.e., H. influenzae, S. pneumoniae, and Neisseria meningitidis) all normally colonize the nasopharynx
neonate: GBS, e. coli, and listeria
4-12 weeks: s. pneumo
3mo to 3y: h. flu. tx- cephalosporins. in children adding steroids decreases risk of deafness
children to young adults: n. meningitides. tx- penicillin or chloramphenicol
elderly: s. pneumo. Risk is increased with trauma (it is the normal flora of the mastoid, ear, sinus, and nose), infection, and sickle cell disease. tx- penicillin
15
Q
What is the organism that causes whipple disease? clinical symptoms, histology and treatment?
A
Whipple disease: It is a chronic multisystem disease caused by Tropheryma whippelii. It is characterized by weight loss, abdominal pain, diarrhea, lymphadenopathy, arthralgia, and Alzheimer’s disease-like neurologic symptoms (10%). Pathologic examination demonstrates foamy macrophages with PAS-positive granules. These are degenerating bacilli. Treatment is with tetracycline.
16
Q
Sarcoid causes non caseating granulomas in what CNS location? What enzyme is elevated in blood? treatment?
A
hypothalamus
ACE
steroids
17
Q
What is Meningovascular syphilis (lues), when does it occur, CNS manifestations?
A
occurs after 7 years and is characterized by subacute or chronic meningitis with perivascular lymphocytes, Heubner arteritis with intimal proliferation and vessel obliteration, and multiple ischemic strokes in the basal ganglia and MCA territory
18
Q
deletions in chromosome 9p in tumors means a loss of?
A
cdkn2a/p16/ARF
19
Q
What is the most frequent bug found in brain abscesses?
A
microaerophillic and anaerobic streptococcus
20
Q
What are the clinical signs of arsenic poisoning? treatment?
A
mees transverse white lines on fingernails, malaise, hyperpigmentation on the palms and soles
BAL
21
Q
What are the clinical signs of lead poisoning? treatment?
A
children: encephalopathy
adults: anemia and demyelinating polyneuropathy. urine excretion of coproporphyrin
BAL, penicillamine, EDTA
22
Q
What are the clinical signs of mercury poisoning? treatment?
A
mad hatter, cerebellar signs, renal tubular necrosis
penicillamine is the treatment. Do not use BAL as it increased brain levels
23
Q
Where are neurofibrillary tangles and plaques found? stain? composition?
A
both intracytoplasmic
both use silver stain
plaques compsed of beta/A4 protein
tangles are immunoreactive to tau protein
24
Q
Herpes infection of the geniculate ganglion (Ramsay Hunt syndrome) symptoms:
A
This may cause dysfunction of CN VII with altered sensation of taste, facial weakness, and vesicular eruptions on the pinna and in the external auditory canal.
25
PML appearance in the brain on imaging and histology?
bilateral, asymmetric, subcortical, spares the cortex, and usually starts in the posterior centrum semiovale. There is minimal cellular infiltration, central destruction of oligodendrocytes, demyelination, and peripheral swollen irregular oligodendrocytes with ground-glass nuclei and intranuclear inclusions of “stick-and-ball” viral particles. CSF is normal
26
prions cause CJD and manifest as:
myoclonus, pyramidal, and extrapyramidal degeneration, dementia, ataxia, and visual deterioration
27
What are the symptoms of prion caused Gerstmann–Sträussler syndrome and inheritance?
ataxia, dysarthria, hyporeflexia, and cognitive decline, without myoclonus. Transmission is both autosomal dominant and sporadic, and Kuru plaques are seen in the cerebellum
28
What are the symptoms of prion induced Fatal familial insomnia and the pathology?
Fatal familial insomnia: Symptoms are sleep disturbance, agitation, mild cognitive changes, and dysautonomia; characterized by thalamic atrophy.
29
Rasmussen chronic encephalitis may be caused by:
CMV infection or antibodies to glutamate receptors
30
Pseudolaminar cortical necrosis: cause, affected cortical layers?
It is caused by generalized hypoxia, not focal. The middle cortical layers are affected (layers 3, 5, and 6), and there is frequent gyriform hemorrhage.
31
Causes, symptoms, and affected nuclei of the stroke syndrome Millard–Gubler syndrome:
From a lesion in the pons. Findings are facial and abducens palsies with contralateral hemiplegia. It is caused by ischemia or tumor and involves CNs VI, VII, and the corticospinal tract.
32
Causes, symptoms, and affected nuclei of the stroke syndrome Benedikt’s syndrome:
From a lesion in the tegmentum of the midbrain caused by ischemia, hemorrhage, TB, or tumor. Findings are oculomotor palsy with contralateral hemiplegia and cerebellar ataxia and tremor. It involves CN III, the red nucleus, corticospinal tract, and brachium conjunctivum.
33
Causes, symptoms, and affected nuclei of the stroke syndrome Weber’s syndrome:
From a lesion in the midbrain caused by vascular occlusion, tumor, or aneurysm. Findings are oculomotor palsy with crossed hemiplegia. It involves CN III and the corticospinal tract.
34
What does Ciliary muscle contraction cause? innervation? effect on eyes refractive power?
—causes the eyeball to become narrower and thus decreases tension on the lens, allowing it to become more spherical. When the ciliary muscle relaxes, the lens is pulled flat. The ciliary muscle is innervated by parasympathetic nerves and serves to increase the eye’s refractive power for accommodation to focus on closer objects.
35
What is the neurotransmitter to the rods and cones? neurotransmitter for amacrine cells? inhibitory or excitatory?
The neurotransmitter of rods and cones is glutamate. Amacrine cells have at least eight types of neurotransmitters; all of them are inhibitory.
36
Parasympathetic innervation of the eye:
Edinger–Westphal nucleus, transmitting via the third nerve → ciliary ganglion behind the eye → short ciliary nerves → ciliary muscle (for accommodation) and iris sphincter (for miosis)
37
Sympathetic innervations of the eye:
T1 level → sympathetic chain → superior cervical ganglion, up along the carotid artery to the small vessels, and then as the long and short ciliary nerves to the eye’s radial iris fibers (for mydriasis), to Müller’s muscle of the eyelid and weakly to the ciliary muscle
38
“What allows for the voluntary retention of urine once a full bladder has induced an increase in bladder parasympathetic tone?
Activation of S2–S4 a-motor neurons causing contraction of the external urethral sphincter striated muscle fibers
39
“This toxin inhibits RNA translation”
Diphtheria toxin
40
“What substance releases factor VIII from von Willebrand factor?”
Thrombin
41
The utricle will respond to stopping at a stop sign or jumping rope?
Stop sign.
Both the utricle and saccule respond to changes in linear acceleration with the utricle being oriented horizontally and the saccule vertically. Deceleration in a motor vehicle traveling straight or a head tilt downward each causes anterior displacement of the otoliths in the macula of the utricle and excites hair cells that respond to movement in that direction. In contrast, the act of jump roping mainly would be sensed by action in the saccule. (A, D) Both of these activities cause a shift of endolymph in the semicircular canals that is detected in the ampulla of each canal. The “ampullae respond to angular acceleration. (B, E) The vestibular system only responds to changes in acceleration and will adapt with no or constant motion in the same direction.
42
A patient with pituitary adenoma presents with arrythmias and airway obstruction. What is the hormone?
“Excess growth hormone in adults results in arthropathy, paresthesias, polyneuropathy, cardiomyopathy, arrhythmias, upper airway obstruction due to palatal/pharyngeal tissue overgrowth, increased risk for malignancies and colon polyps, and diabetes.
43
What are the major proinflammatory cytokines? Anti inflammatory?
“major proinflammatory cytokines are the interleukins (IL) IL-1, IL-6, IL-8, TNF-α (tumor necrosis factor-alpha), and IFN-γ (interferongamma). These produce fever, tissue destruction, and inflammation. The major anti-inflammatory cytokines include IL-4, IL-6, IL-10, IL-11, and IL-13. Of note, IL-6 can be anti- or proinflammatory depending on how it is used in a signaling cascade
44
“What is a miniature end-plate potential?”
“Response of the postsynaptic terminal caused by the release of a single vesicle into the synaptic cleft
45
When do T-type calcium channels open during the action potential?
“Between the resting and threshold potentials
Found initially in cardiac smooth muscle cells, T-type calcium channels are unique voltage-gated calcium channels that open at around −55 mV, which is slightly higher than the resting potential in cardiac cells of −60 mV. T-type calcium channels open to allow a large calcium flux into the cell to aid in the depolarization required to reach the triggering threshold for an action potential.”
46
How do class 3 cardiac antiarrhythmics (potassium channel blockers) affect action potentials and conduction velocity?
Prolong action potential duration and maintain normal conduction velocity
By blocking only potassium channels (notably the inward rectifier channels), hyperpolarization (returning to a negative resting potential) is inhibited, and cardiac cells remain depolarized longer. This prolongs the action potential and the refractory period. Conduction velocity is unaffected, as there is no prevention of the opening of subsequent sodium channels and depolarizing the adjacent membrane segments
47
how does caffeine exert its effects?
“Phosphodiesterase inhibition
By inhibiting phosphodiesterase, cAMP degradation is reduced. All of the actions of caffeine serve to upregulate the nervous system in a stimulatory manner. (A) Caffeine competitively inhibits glycine receptors. (C) Caffeine competitively inhibits adenosine receptors.”
48
What molecules are needed to activate the ligand-gated component of NMDA receptors?
“Two molecules of either glutamate or aspartate and two molecules of either glycine or serine need to bind to an NMDA receptor in order to activate it.”
49
What is the mechanism of action of bisphosphonates?
“Inhibition of osteoclasts
Bisphosphonates bind to calcium and are taken up by osteoclasts. Bisphosphonates then induce apoptosis of these bone-reabsorbing cells. ”
50
Where does GABA bind on the GABAa receptor? where do benzos bind?
between the alpha and beta subunits
benzos between the alpha and gamma
51
What are the first cleavage products of proopiomelanocortin?
“ACTH, β-lipotrophin, and γ-MSH”
52
Pursuit movements definition a d brainstem area involved?
keep the eyes fixed on a moving object. Even if the visual cortex is destroyed, the superior colliculus (with visuotopic representation) turns the head toward a visual disturbance by medial longitudinal fasciculus (MLF) input.
53
What happens during testing of the H-reflex in electrophysiological studies when stimulation is increased to a supramaximal level?
“ The H-wave disappears
The H-wave is the electrophysiological equivalent of the stretch reflex and represents the muscle’s electrical response to a square wave stimulus to the skin that first propagates in the antidromic direction (away from the muscle) to the cell bodies. The reflex arc continues with an electrical signal sent in the orthodromic direction (toward the muscle) to elicit a response. This response is the H-wave. As stimulation amplitude increases, the H-wave diminishes and disappears with supramaximal stimulation. It is most useful for evaluating the Ia sensory afferents. (B, D) The M-wave is the orthodromic response recorded in the muscle to electrical stimulation of the skin overlying the muscle. It bypasses the reflex arc and increases with increasing stimulation amplitude. (E) The F-wave increases with increases in amplitude but not to the extent seen in the M-wave. The F-wave is the result of alpha-fiber stimulation and is useful to evaluate proximal (near the spinal cord) nerve conduction velocities”
The Hoffmann reflex, or H-reflex, was described by stimulating type Ia afferent sensory fibers at various intensities. At low intensity, the type Ia fibers result in a monosynaptic reflex arc with the efferent α motor, which results in activation of a motor unit recorded as an H-reflex. At higher intensities, there is direct activation of the α motor neuron terminus and motor unit (M-wave) which precedes the H-reflex wave that arises from orthodromic propagation. At even higher stimulus intensities, an antidromic wave through the motor neuron results in cancellation of the orthodromic H-reflex wave; and accordingly, only a large M-wave is detected. Non-contractile muscle spindle fibers are innervated by Ia sensory afferents conveying information of stretch and velocity, which excite efferent α motor neurons in the ventral horn
54
What is the substrate for nitric oxide synthetase?
arginine
55
what is the approximate resting membrane potential of a neuron, and conductance of what ion is most responsible for determining this potential?
-65 mV
potassium
56
Secretion of what proteins from the notochord establishes the ventral pole of the dorsal-ventral axis in the developing nervous system?
sonic hedgehog proteins
57
Where is a lesion that causes alexia without agraphia located?
The lesion is located in the left visual cortex and the splenium of corpus callosum which disconnects the right visual cortex from the left angular gyrus. The vessel supplying this territory will be the left posterior cerebral artery.
58
Which of the following nuclei has cholinergic output and neocortical visual perception function?
nucleus basalis is the primary nucleus secreting acetylcholine to various areas of the cerebral cortex, including the lateral geniculate nucleus where it plays a role in neocortical visual perception. The lateral geniculate nucleus has acetylcholine receptors that are also influential in this pathway, but does not have cholinergic output
59
Which of the following language deficits is most often encountered acutely after damage to the dominant supplementary motor area?
Supplementary Motor area aphasia, occuring after unilatleral damage to the dominant hemisphere, generatlly manifests as reduced spontaneous speech, with intact repetition, naming, and comprehension. Akinetic mutism generally occurs only with bilateral SMA damage.
60
What is winters formula?
Predicts PaCO2 in metabolic acidosis
Predicted PaCO2=1.5x[HCO3-]+8
61
Pathology shows blood-filled cavernous spaces separated by fibrous septa surrounded by fibroblasts, histiocytes, and multi-nucleated giant cells, but not endothelium. Which of the following is the most likely diagnosis?
imaging shows an aneurysmal bone cyst. On imaging these are sharply defined, expansile osteolytic lesions, with thin sclerotic margins. The occurrence of a concomitant fibrous dysplasia and aneurysmal bone cysts in calvarium is exceedingly rare, but there is a report that a secondary form of aneurysmal bone cysts may arise from a disruption in the osseous circulation caused by a primary lesion
62
autosomal dominant inherited disorder that has been reported in association with heterozygous mutations in the RASA1 gene, which encodes the protein RASp21?
Capillary malformation-arteriovenous malformation (CM-AVM) syndrome is characterized by the presence of multiple small capillary malformations mostly localized on the face and limbs
63
polymicrogyria and schizencephaly are Disorders of:
cortical organization
64
hemimegalencephaly, cortical tubers, and focal cortical dysplasia are Disorders of:
cellular proliferation
65
Lissencephaly and subcortical band heterotopia comprise a spectrum of malformations of cortical development caused by:
Lissencephaly and subcortical band heterotopia comprise a spectrum of malformations of cortical development caused by insufficient neuronal migration
66
What is skew deviation? Occurs during eye exam. Its a sign of damage to what CNS location?
Skew deviation is an abnormality of ocular motility in which the eyes move in opposite directions as the patient looks upward. This is a sign of brainstem or cerebellar infarction, causing aberrant prenuclear vestibular input into the oculomotor nuclei.
67
Staghorn vasculature is associated with which tumor?
hemangiopericytoma
68
Pheochromocytoma are associated with which tumor syndromes?
Pheochromocytoma are associated with MEN-2 syndrome and glomus jugularae tumors and VHL
69
What medication classes can cause a tremor?
Medication classes most likely to cause tremor include beta-agonists (e.g., bronchodilators such as salmeterol), selective serotonin reuptake inhibitors, and tricyclic antidepressants.
70
What enzyme promotes the conversion of 5-hydroxy-trytophan to serotonin?
Aromatic amino acid decarboxylase using vitamin B6 as a cofactor
71
What role do L-type voltage-dependent calcium channels play in muscle contraction?
Respond to depolarization and activate calcium channels on the sarcoplasmic reticulum
72
How does parathyroid hormone increase the serum calcium level? What does calcitonin do?
Inhibits osteoblasts
calcitonin is secreted by the thyroid gland and inhibits serum levels of calcium
73
What makes an action potential propagate in only one direction once it has been initiated?
The absolute refractory period
“The absolute refractory period is determined by the inability of voltage-gated sodium channels to open for a period of time once they have opened and closed during an action potential. Without a large sodium flux from outside to inside the axon, there can be no depolarization and thus no subsequent action potential. The action potential thus must propagate in an anterograde fashion to a portion of the axon where the sodium channels have not been activated and closed recently. ”
74
What is hexamethonium? how would it affect post synaptic parasympathetic neurons?
“Hexamethonium is an antagonist of nicotinic acetylcholine receptors and thus is a ganglionic blocker in the autonomic nervous system. It binds to the nicotinic acetylcholine receptors but not in the binding site for acetylcholine. Hexamethonium has no effect on the postsynaptic muscarinic acetylcholine receptors.”
75
Steroid enter the cells by what type of transport?
simple diffusion
76
What i the result of light falling upon the photoreceptor cells of the retina?
“As in the auditory and vestibular systems, the stimulus (light) induces hyperpolarization of the retinal cells, which is due to the closure of sodium channels and reduction of the inward sodium flux of sodium in the case of phototransduction.”
77
Vitamin K is required for synthesis of which clotting cascade factors?
“prothrombin (factor II), factor VII, factor IX, factor X, protein C, protein S, and protein Z”
78
What is the mechanism of action of HCTZ?
inhibition of the sodium-chloride cotransporters in the distal tubules
79
What are the major characteristics associated with protein molecules that prevent them from being filtered into the bowman capsule in the renal glomerulus?
Low oncotic pressure and positive charge
“The basement membrane and podocytic epithelium in the glomerulus have a positive charge and thus resist passage of negatively charged molecules. In addition, the effective pore size in the glomerular wall is about 8 nm, preventing passage of most proteins and other large molecules.”
80
What causes scalloping of the vertebral bodies?
Intradural tumors or lesions that increasw pressure
Other causes of vertebral body scalloping can include uncontrolled communicating hydrocephalus, connective tissue disorders (e.g., Marfan’s), dural ectasia, NF1, and achondroplasia.
81
The nucleus accumbens is most associated with which of the following functions?
The nucleus accumbens is thought to play a critical role in learning and motivation. It has rich connectivity with midbrain dopaminergic neurons and prefrontal and limbic areas that may help reinforce certain decisions. Many animal studies have implicated the ventral striatum (nucleus accumbens and olfactory tubercle) in the processing of reward information. In humans, fMRI studies have demonstrated that the ventral striatum is sensitive to a wide array of reward features. It exhibits signal changes in response to monetary reward and loss even if no physical money is given to an individual and only abstract remuneration occurs.
82
What makes up the ventrobasal complex?
VPL, VPM, and the posterior thalamic nucleus
83
Seizure focus for vertiginous sensations?
Foci in the superoposterior temporal lobe near the junction with the parietal lobe
84
How does excess zinc affect copper levels
Inhibits absorption and leads to copper deficiency
85
Which ion is responsible for blocking the ion pore at the NMDA glutamate receptor at resting membrane potential
Magnesium
86
what is the intermediolateral nucleus?
serves the thoracic spinal cord for outgoing sympathetic signal
87
what is the nucleus of clark
conveys info to related unconscious proprioception in thoracic spine
88
spinal trigeminal fibers carry what type of sensory?
pain and touch from the face
89
Which mechanisms is most likely to explain the antinociceptive effects of cannabinoids
Binding to pre-synaptic membrane receptors to decrease excitability
90
Which of the following channels opens in response to GABAB receptor activation?
Potassium
91
Projection axons in the olfactory tract originate in which of the following cells?
Mitral cells of the olfactory bulb
Bipolar primary olfactory neurons originate in the olfactory cells within the olfactory epithelium, and project to secord order neurons in the olfactory bulb called mitral cells. Axons from mitral cells leave the olfactory bulb through the olfactory tract located under the frontal lobe to the primary olfactory cortex (piriform cortex), which is located on the inferior surface of the temporal lobe. The entorhinal cortex is an area of the brain's allocortex, located in the medial temporal lobe, whose functions include being a widespread network hub for memory, navigation, and the perception of time.
92
The anatomic basis of the blood-brain barrier is the
Capillary Endothelial Cells, Basement Membrane, Neuroglial Membrane, Glial Podocytes
93
The mass of choroid plexus that protrudes through the lateral aperture of the fourth ventricle (foramen of Luschka) lies
on the posterior surface of the glossopharyngeal and vagus nerves
94
A lesion to the pulvinar nucleus of the thalamus can result in:
neglect syndrome
located in most posterior part of thalamus and is associated with visual pathways
95
What structure is the target for taste afferent fibers?
nucleus tractus solitarius
also receives afferents from chemoreceptors in the aortic and carotid bodies
96
What skin mechanoreceptors detect rapid vibrations and pressure?
pacinian corpuslces
97
The deep petrosal nerve is what type of nerve with what type of function?
sympathetic nerve that unites with the greater superficial petrosal nerve to form the vidian nerve
vidian nerve carries the sympathetics that innervate the pterygopalatine ganglion
98
What leptomemingeal layer is composed only of a single layer?
spinal dura
99
Which structure runs through the petrotympanic fissure?
chorda tympani
100
what is the velum interpositum?
The potential space where the internal cerebral veins run
located in the third ventricle
101
What structure in the medial limbic circuit is the major output of the thalamus? What is papez circuit?
Cingulate gyrus
The papez circuit begins in the hippocampus (subiclulum) --> fornix --> mammillary bodies --> mammillothalamic tract --> anterior thalamic nucleus --> cingulum --> entorhinal cortex --> hippocampus
102
Where is the flocculonodular lobe of the cerbellum located?
anterior to and between the anterior and posterior cerebellar lobes
103
uncinate fasciculus in the cerebellum connects...? What does the juxtarestiform body connect?
uncinate fasciculus in the cerebellum connects the fastigial nuclei to the contralateral vestibular nuclei and travels around the superior cerebellar peduncle, while the juxtarestiform body connects the fastigial nuclei to the ipsilateral vestibular nuclei and travels in the inferior cerebellar peduncle
104
cingulate sulcus separates the...? and the marginal limb seperates the...?
cingulate gyrus from the superior frontal gyrus, while its marginal limb separates the paracentral lobule from the precuneus.
105
The optic vesicles are diverticula of which embryologic division of the brain?
Diencephalon
The diencephalon gives rise to the thalamus, hypothalamus, posterior pituitary, and optic vesicles
106
The organ of Corti responsible for hearing is located on the
basilar membrane
The organ of Corti is composed of hair cells responsible for hearing. These are located on the basilar membrane that separates scala tympani from scala media and their cilia project into the tectorial membrane. Activation of the hair cells stimulates the cochlear nerve endings. The vestibular (Reissner’s) membrane separates scala media from scala vestibuli.
107
Neurotransmitter release from the presynaptic terminal is caused by
Ca++ influx
108
The plateau phase of the cardiac Purkinje cell action potential is caused by
Ca++ influx
109
The endolymph is present in all of the following structures, except
Scala vestibuli
present in:
Membranous labyrinth
Utricle
Saccule
Semicircular canals
110
Sectioning the corpus callosum in a right-handed person can result in all of the following, except
Left constructional apraxia
One of the main risks of corpus callosotomy is disconnection syndrome. Constructional apraxia is inability to perform tasks requiring spatial processing (e.g., copying geometric forms). This is processed in the right hemisphere. Therefore, in disconnection syndrome, the left hand is intact but the right hand is affected. A, C and D are left hemispheric functions, they are normal on the right side of the body and lost on the left side. If different words are presented to each ear simultaneously (dichotically), the left ear signal is suppressed by the stronger contralateral signal.
Left-hand motor apraxia to verbal commands
Left auditory suppression
Anomia for objects in the left visual field
Anomia for objects in the left hand when the eyes are closed
111
The best medical treatment of Paget’s disease of the spine includes
Bisphosphonates
Bisphosphonates like pamidronate as well as calcitonin (salmon-derived) are used to treat severe Paget’s disease. Patients usually have hypercalcemia and hypercalciuria and are prone to kidney stones. Lab work also shows increased serum alkaline phosphatase and urine hydroxyproline. PTH increases serum calcium and is contra indicated.
112
Which of the following best describes bromocriptine’s mechanism of action?
Partial antagonist for the D1 dopamine receptor and selective agonist for the D2 dopamine receptor.
