2011 module exam Flashcards
In the above figure, the line on the top represents bone conduction ([-) while the line at the bottom represents air conduction (X-). Where would you expect the pathology to be?
a. Middle ear
b. Inner hair cells
c. Outer hair cells
d. Cochlear nerve
a. Middle ear
[The above figure represents conductive hearing loss, where bone conduction is better than air conduction. This is due to the fact that intensity needed for bone conduction is lower than the intensity needed for air conduction. Intensity is represented by the vertical line and frequency the horizontal line. The only choice where a pathology would cause conductive hearing loss is a]
1- Blockage of the anterior spinal artery leads to:
loss of pain and temperature on both sides
Which of the following when lesioned causes Spastic paralysis of the distal muscles on the right?
Damage to the right lateral corticospinal tract
Loss of reflex turning of the head in response to visual stimuli is because of a lesion in:
tectospinal tract
Which of the following receptors is responsible for detection of vibrations?
Pacinian
What is the “labeled-line” theory?
Each receptor is connected to a specific area of the cortex
What is a fast adapting receptor?
Meissner’s
What recognizes various modalities of sensation (or conveys more than one type of signal)?
Free nerve endings
What happens in the reciprocal excitation in golgi tendon reflex?
Activation of Ib afferents and excitation of antagonist muscles
Which of the following is recruited in the adaptive response in the withdrawal reflex elicited by high intensity pain for response amplification?
Propriospinal fibers
[These are the fibers that activate several spinal cord segments with increasing pain intensity in the flexor withdrawal reflex]
Which of the following nuclei is an origin of some of the fibers in the medial leminiscus?
Gracile nucleus (nucleus gracilis)
Which tract conveys information about right leg position?
Right fasiculus gracilus (gracile fasiculus)
How do fast adapting receptors operate?
By detecting the stimulus at the beginning and the end
Through which of these structures does the corticospinal tract pass?
Basilar part of the pons
Which of the following nuclei projects preganglionic parasympathetic fibers to the otic ganglion?
Inferior salivatory nucleus
Which parasympathetic nucleus is associated with the facial nerve?
Superior salivatory nucleus
In which of these nuclei would you find pseudounipolar neurons?
Mesencephalic nucleus of the trigeminal nerve
What carries sensation of pain and temperature from the face?
Spinal nucleus of the trigeminal nerve
A patient has a droopy left upper eyelid. On examination, you find that his left pupil is more constricted than his right pupil. What is the condition?
Horner’s syndrome
[It is a classical triad of ptosis(droopy upper eyelid), miosis (pupillary constriction), and anhidrosis (no sweating) due to disruption of the sympathetic innervation to the face]
What is true regarding lipid metabolism in the brain?
a. Oxidation of very long chain fatty acids in peroxisomes
b. Synthesis of linolenic acid
a. Oxidation of very long chain fatty acids in peroxisomes
myelin has components which aren’t present in any other membrane in the body. To which family do they belong?
protein
What would decreased production of glycosphingolipids lead to?
hypomyelination
Which of the following proteins is mutated in neurofibromatosis 2, which is characterized by the development of schwannomas?
Merlin
In myasthenia gravis there’s discontinuity between the nerve terminal and the muscle. What’s the mechanism that mediates that?
Blocking antibodies
A 35-year-old man on chemotherapy for leukemia develops limb weakness, unsteady gait, and diplopia. He then exhibited memory problems and died a few months later. Autopsy shows softened, granular appearance of the white matter. What is the diagnosis?
Progressive multifocal leukoencephalopathy (PML)
Which condition is characterized by galactocerebroside-β- galactosidase deficiency?
Krabbe’s disease
A 52-year-old man on diuretics with a sodium of 118 mmol/L. What is the condition?
Central pontine myelinosis
Which artery when blocked causes damage to the primary somatosensory cortex?
Middle cerebral artery
In which cortex would you find the large pyramidal cells?
a. Primary motor cortex
b. Premotor cortex
a. Primary motor cortex
The anterior commissure connects which parts of the brain?
The temporal lobes
Which reflex would be altered if the posterior commissure is affected?
Light
neurons from the Ventral posterolateral nucleus (VPL) and the ventral posteromedial nucleus (VPM) go to which of the following parts of the cortex?
Postcentral gyrus [the primary somatosensory cortex]
What is supplied by the posterior cerebral artery?
Primary visual cortex
Damage to the superior temporal gyrus would affect:
Wernicke’s area
What nuclear medicine method is used to asses cerebral perfusion?
Tc-99m HMPAO SPECT
What is used to evaluate the risk of stroke in cerebral ischemia?
Tc-99m HMPAO SPECT with acetazolamide
What percentage of stroke patients will be dependent on others for daily activities?
More than 50%
Which neurotransmitter causes neuronal toxicity during ischemia?
L-glutamate
A 60-year-old man with uncontrolled hypertension presents with loss of consciousness. After waking up he can’t speak and has paralysis of the right leg. Which of the following is the most likely cause?
a. Basal ganglia hemorrhage
b. Middle cerebral artery embolus
c. Central pontine myelinosis
a. Basal ganglia hemorrhage
c. Central pontine myelinosis
[a is the correct answer because an intraparanchymal hemorrhage would increase the intracranial pressure and produce a mass effect, leading to herniation of the cingulate gyrus (a subfalcine/cingulate herniation). This herniation would compress the anterior cerebral artery leading to leg weakness.
MCA embolus would not cause leg weakness, and the history and presentation is not that of central pontine myelinosis]
A 37-year-old female was sitting at her desk when she experienced a severe headache. Her CSF shows red blood cells without pleocytosis. What could be the cause?
Ruptured berry aneurysm
A 55-year-old male had his mean arterial pressure drop to 40 mmHg due to heart failure. What would be a consequence of this drop on the hemodynamics of the brain?
a. Reduced cerebral blood volume
b. Increased intracranial pressure
b. Increased intracranial pressure
[Dr. Zoran confirmed this]
Which of the following is responsible for regulating cerebral blood flow under normal conditions?
Neuronal release of glutamate
Which of the following increases Cerebral blood flow in normal conditions?
Glutamate release
Which of the following produces minimal change in CBF?
Increased O2 in the interstitial fluid
Which of the following decreases cerebral blood flow?
1- Release of arachidonic acid by astrocytes
2- Increased pH of interstitial fluid
1- Release of arachidonic acid by astrocytes
2- Increased pH of interstitial fluid
[Dr. Zoran counted BOTH as correct]
Cerebral blood flow was reduced to 20 ml/min/100g for 90 minutes and then was restored to the normal value of 50 ml/min/100g. What would be the consequence?
Transient impaired function with full recovery
[this is the concept of the penumbra]
What will be the defect when a person has bilateral injury to the posterior lateral partietal cortex?
Unable to reach for objects
A patient has a lesion in the occipital association cortex. What will be observed?
He can name objects but he can’t draw them
When there is a defect in perception of shape, color, and texture, what part of the association cortex is affected?
Temporal association cortex
A lesion in the parietal association cortex would result in:
the patient neglecting his left side
An 83-year-old suffered from a stroke immediately after a hip fracture. What might be the cause?
Fat embolism [long bone fracture=fat embolism]
Which party of the brain when lesioned would affect the working memory?
Anterior association area (prefrontal cortex)
Fibers carrying information from the posterior spinocerebellar tract giving information about limb movement go to which part of the cerebellar cortex?
Intermediate
Which part of the cerebellum when damaged would cause nystagmus?
Flocculonodular lobe
Damage to the cerebellum causes:
a. incoordination of movement because they cannot perceive their
limb position
b. unable to control movement although the patient is totally aware of the abnormality
b. unable to control movement although the patient is totally aware of the abnormality
Where do we find neuromelanin pigmented neurons?
Substantia nigra
Substantia nigra
Which of the following cells has the same lineage as monocytes?
Microglia
In an epidemiological study, you investigate a screening test for iron deficiency anemia has a pretest probability is 10%. However, you encounter a patient who has a Pre-test probability of 90%. What will be the effect on the test parameters?
Sensitivity and specificity: Same
PPV: increase
NPV: decrease
Sensitivity and specificity: Same
PPV: increase
NPV: decrease
What’s a general characteristic of CAG expansion repeats?
They are transcribed and translated
What is true of the CGG repeats in fragile X syndrome?
They occur in the promoter region of the gene
Entacapone is a Levodopa optimizer given with it to enhance its CNS concentration. What is its mechanism of action?
Inhibition of catechol-o-methyl-transferase
What mediates the go-stop pattern of the cerebellum?
a. Inhibitory influence from the purkinje cells
b. Because both mossy and climbing fibers are excitatory
a. Inhibitory influence from the purkinje cells
[b is not correct. It was a mistake in the 2009 tafree’3. We asked Dr. Pavlik and he confirmed the first choice]
The cerebellar learning of fast skilled movements is based on changes in the cerebellar cortex excitation by induced by stimulation of climbing fibers. What is this mechanism?
Long-term depression
What is the characteristic of the output of the cerebellum?
Go-stop character