Exam III Written Questions Flashcards
A 79-year-old woman is admitted to the emergency room after she was found unconscious in her apartment. After she regained consciousness, a neurologic examination indicated that she suffered a stroke with paralysis of the right arm and leg as well as loss of speech.
The most likely region affected by the stroke that could account for limb paralysis is:
a. Prefrontal cortex
b. Precentral gyrus
c. Postcentral gyrus
d. Superior temporal gyrus
e. Parietal lobe
b. Precentral gyrus
The primary motor cortex is located in the precentral gyrus, which is organized somatotopically. The functions of the upper and lower limbs are represented in different regions along the precentral gyrus. The postcentral gyrus represents a primary somesthetic receiving area for pain, temperature, pressure, kinesthetic, and tactile impulses from the periphery. Although the superior frontal gyrus contains certain groups of neurons (the supplementary and premotor motor areas) that also con- tribute to motor functions, it is not a primary motor area. The superior parietal lobule is associated with sensory discrimina- tion processes and with the programming of signals to the pre- motor cortex. The posterior parietal cortex represents a region of sensorimotor integration and the organization of complex response patterns.
A 79-year-old woman is admitted to the emergency room after she was found unconscious in her apartment. After she regained consciousness, a neurologic examination indicated that she suffered a stroke with paralysis of the right arm and leg as well as loss of speech.
The loss of speech in this patient was due mainly to damage of the:
a. Superior frontal cortex
b. Inferior temporal gyrus
c. Inferior frontal gyrus
d. Occipital cortex
e. Medial aspect of parietal cortex
c. Inferior frontal gyrus
The posterior aspect of the inferior frontal gyrus contains a region called “Broca’s motor speech” area. Lesions affecting this region produce motor aphasia, which is characterized by a loss of ability to express thoughts in a meaningful manner. The superior aspect of the frontal cortex is associated with move- ments of the lower limbs, the inferior temporal gyrus is associ- ated with perceptual functions, the occipital cortex is associated with vision, and the medial aspect of the parietal lobe is associ- ated with somatosensory functions involving the leg.
During routine surgery for appendicitis, a clot is released from the lung of a 75-year-old man, causing the patient to remain unconscious for a period of 1 week. Upon regain- ing consciousness, the patient finds that he is unable to maintain his balance and, further, displays tremors while at- tempting to produce a purposeful movement. In addition, the patient’s movements are not smooth but jerky and lack coordination. The region affected most likely include the:
a. Spinal cord
b. Medulla
c. Pons
d. Midbrain
e. Cerebellum
e. Cerebellum
Although the spinal cord, medulla, pons, and midbrain play important roles in motor functions, the primary functions of the cerebellum include regulation of motor functions. Damage to parts of this structure causes a loss of balance, loss of coordination of movements, and tremors. Unlike the cerebel- lum, none of the other regions has a direct role in the regula- tion of these processes.
A magnetic resonance image scan taken of a 60-year-old woman revealed the presence of a tumor on the base of the brain that was situated just anterior to the pituitary and that impinged upon the adjoining neural tissue. A likely deficit resulting from this tumor includes:
a. Loss of movement of upper limbs
b. Speech impairment
c. Difficulties in breathing
d. Changes in emotionality
e. Loss of ability to experience pain
d. Changes in emotionality
The optic nerve enters the brain at the level of the far anterior hypothalamus. Tumors of this region of the base of the brain commonly affect the hypothalamus, which plays an impor- tant role in the regulation of emotional behavior and auto- nomic functions. Such tumors would also likely affect visual functions. Movements of the limbs are affected by lesions of the internal capsule or precentral gyrus; speech impair- ment is affected by damage to the inferior frontal or superior temporal gyrus; breathing is affected by the lower brainstem; and pain is affected by parts of the brainstem, thalamus, and postcentral gyrus.
A 45-year-old man complained about having recurring head- aches over a period of weeks. Subsequent tests revealed the presence of a tumor along the lateral wall of the anterior horn of the lateral ventricle, which did not produce hydrocephalus. One region that would be directly affected by the tumor is the:
a. Caudate nucleus
b. Putamen
c. Globus pallidus
d. Hippocampus
e. Cingulate gyrus
a. Caudate nucleus
The head of the caudate nucleus is located adjacent to the lateral aspect of the anterior horn of the lateral ventricle. Therefore, a tumor in this region would include the head of the caudate nucleus. The putamen and globus pallidus lie lateral to the caudate nucleus at a position away from the lateral ventricle, the hippocampus lies adjacent to the infe- rior horn of the lateral ventricle, and the cingulate gyrus lies above the corpus callosum in a position not in proximity to the lateral ventricle.
A two day old female infant presents with a small pigmented area at the midline on her lower back. Close examination reveals a small tuft of delicate hairs associated with a small cutaneous dimple. Which of the following most closely signifies with this defect?
A. Rachischisis
B. Encephalocele
C. Spina bifida aperta
D. Spina bifida cystica
E. Spina bifida occulta
E. Spina bifida occulta
A stillborn infant was noted to have a grossly abnormal skull and cerebrum. The parietal bones, most of the occipital bones, and most of the frontal bones above the orbits were absent. A malformed remnant of the cerebrum, with few recognizable structures, was exposed at the site of the skull defect. The most likely explanation for this malformation was:
A. defective formation or migration of neural crest cells
B. failure of closure of the rostral neuropore
C. failure of closure of the caudal neuropore
D. blockage of the cerebral aqueduct
E. increased proliferation or migration of CNS neurocytes
B. failure of closure of the rostral neuropore
A 7 year old boy is brought to the pediatrician by his mother, who complains that the boy has had progressive difficulty seeing/reading the assignments posted on the board by the teacher. Examination reveals a boy who is noticeably small for his age, has partial vision loss in both eyes peripherally, but otherwise appears healthy. MRI of the brain reveals a craniopharyngioma – Rathke’s pouch tumor – which is an aberrant outpocketing of the stomodeum. Which one of the following is most directly involved in the developmental defect seen in this boy?
A. Adenohypophysis
B. Neurohypophysis
C. Optic chiasm
D. Hypothalamus
E. Thalamus
A. Adenohypophysis
A child is born with a large mass on the forehead, a partially cleft nose, and ocular hypertelorism (widely spaced orbits). CT and MRI reveal a defect in the frontal bone and a mass containing fluid, portions of the frontal lobe, and a cavity that is continuous with the anterior horn of the right lateral ventricle. Which of the following best describes this type of mass?
A. Meningocele
B. Meningoencephalocele
C. Meningohydroencephalocele
D. Meningomyelocele
E. Microencephaly
C. Meningohydroencephalocele
A 59-year-old man is evaluated for lower limb ataxia and bladder dysfunction. Physical examination demonstrates small irregular pupils that constrict with accommodation but not in response to light. A VDRL test is positive. A CT scan of the spinal cord would most likely demonstrate atrophy of which of the following structures?
(A) Dorsal column
(B) Dorsal horn
(C) Lateral column
(D) Ventral column
(E) Ventral horn
(A) Dorsal column
A 66 year old anatomy professor with a beard wakes up one morning and finds that he cannot feel the lower left side of his body and right face. He calls to his wife but she cannot understand what he is saying. What may be the cause?
A. Left MCA stroke
B. ALS
C. Diabetic neuropathy
D. Right medullary stroke
E. Thoracic syringomyelia
D. Right medullary stroke
Which one of the following events is elicited by the mechanical displacement of the cochlear hair cell stereocilia towards the kinocilium?
A. There is an influx of K+ (potassium) through the membranes of the cilia, which is followed by an influx of Ca2+ (calcium) through the voltage-gated Ca2+ channels.
B. The hair cells on which the cilia are located are hyperpolarized.
C. Efflux of Ca2+ (calcium) through the voltage-gated channels located in the hair cell membrane occurs.
D. An inhibitory transmitter (probably gamma aminobutyric acid) is released by the hair cell.
E. There is an influx of Na+ (sodium) through the membranes of the cilia, the hair cell is depolarized, and an action potential is elicited in the afferent nerve terminal.
A. There is an influx of K+ (potassium) through the membranes of the cilia, which is followed by an influx of Ca2+ (calcium) through the voltage-gated Ca2+ channels.
A 47-year-old woman was admitted to a local hospital after complaining of a gradual loss of hearing in one ear over time. In addition, the patient also reported some unsteadiness in balance that developed after the initial hearing loss. A magnetic resonance imaging (MRI) scan and a thorough neurological examination further revealed a facial palsy and a loss of corneal reflex on the side of the face ipsilateral to the hearing loss. The most likely cause of this disorder as revealed by the MRI and clinical evaluations was:
A. A tumor in the region extending from the external to the middle ear
B. An acoustic neuroma of the cerebellopontine angle affecting cranial nerve VIII
C. A vascular occlusion affecting the medial two thirds of the basilar pons
D. A tumor affecting the midline region of the cerebellar cortex
E. A vascular lesion involving the medial longitudinal fasciculus and adjoining regions of the dorsal pons
B. An acoustic neuroma of the cerebellopontine angle affecting cranial nerve VIII
A 27-year-old man who had been in good health reported to his primary physician that he had episodes of dizziness. Over time, the dizziness tended to decrease, but the patient began to experience tinnitus and hearing loss, and both of these symptoms became progressively worse. A neurological examination revealed no other signs of neurological dysfunctions. The patient was treated with anticholinergics with some degree of success. The most likely basis of the disorder in this patient is:
A. A lesion of the medial longitudinal fasciculus
B. A tumor of the cerebellum
C. A tumor impinging on CN VIII and CN VII at the cerebellopontine angle
D. An abnormal volume of endolymph of the inner ear
E. A lesion of the dorsolateral pons affecting the lateral lemniscus
D. An abnormal volume of endolymph of the inner ear
A virus invades the stria vascularis cells of the left inner ear, resulting in a significant increase in the concentration of potassium in the endolymph. Which one of the following would you expect to happen?
A. The outer hair cells hyperpolarize, causing a high pitched “ringing” in the ears.
B. The patient complains of muffled sounds due to smaller receptor potentials in the inner hair cells.
C. The hair cells in the left ampulae depolarize to a greater extent than those on the right, and the patient complains of vertigo/dizziness.
D. The otoconia hyperpolarize, and the patient feels “light-headed.”
C. The hair cells in the left ampulae depolarize to a greater extent than those on the right, and the patient complains of vertigo/dizziness.
