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1. Regarding the role of the basal ganglia in motor control
a) Disorders of the basal ganglia produce a marked loss of both sensation and motor control.
b) Parkinsonism is caused by neuronal degeneration within the substantia nigra.
c) The globus pallidus projects directly to the cerebral cortex.
d) Acetylcholine is the predominant neurotransmitter of the substantia nigra.
(b) Parkinsonism is caused by neuronal degeneration within the substantia nigra.
Feedback: The basal ganglia are involved in motor control via their influence on the motor cortex. The globus pallidus projects to the cerebral cortex via the thalamus. The principal neurotransmitter of the substantia nigra is dopamine.
2. Regarding the role of the cerebellum
a) Purkinje neurons lie in the deep cerebellar nuclei.
b) The cerebellum has a direct efferent projection to the motor cortex.
c) Hemiballismus is a sign of cerebellar damage.
d) The cerebellar hemispheres control and receive inputs from ipsilateral muscles.
(d) The cerebellar hemispheres control and receive inputs from ipsilateral muscles.
Feedback: Purkinje cells lie in the cerebellar cortex. There is no direct efferent projection from the cerebellum to the motor cortex although a number of indirect pathways exist. Hemiballismus is a sign of damage to the basal ganglia.
3. Concerning the motor cortex
a) The motor areas of the cortex are situated in the postcentral gyrus.
b) Following a cerebral hemorrhage affecting the precentral gyrus of the right hemisphere, the patient feels no sensation on the left side of their body.
c) The corticospinal tract provides the only connection between the motor cortical areas and the spinal cord.
d) Motor areas of the cortex receive somatosensory input via the thalamus.
(d) Motor areas of the cortex receive somatosensory input via the thalamus.
Feedback: The precentral gyrus of the right cerebral hemisphere contains the motor areas that control the muscles of the left (contralateral) side of the body. The affected individual would therefore experience a loss of movement on the left side. In addition to the corticospinal tract, descending extrapyramidal pathways connect the motor cortex with the spinal cord.
4. Regarding the descending motor pathways
a) The axons of the corticospinal tract mainly synapse directly with motor neurons in the spinal cord.
b) The rubrospinal tract exerts its major influence on the muscles of the extremities.
c) The reticulospinal tracts are largely decussated (crossed).
d) Damage to the pyramidal tract results in a loss of fine control of the muscles on the same side of the body.
(b) The rubrospinal tract exerts its major influence on the muscles of the extremities.
Feedback: Most corticospinal neurons make contact with spinal interneurons. The rubrospinal neurons mainly influence the muscles of the extremities. The neurons of the reticulospinal tracts are largely uncrossed. The pyramidal tract is crossed and provides fine control of muscles on the opposite side of the body
5. Regarding the control of speech
a) In left-handed people the faculty of speech is mainly located in the right hemisphere.
b) Individuals affected by Broca’s aphasia are able to speak only with great difficulty.
c) An individual with Broca’s aphasia will have paralysis of the lips and tongue
d) Wernicke’s aphasia results from damage to the frontal speech area
(b) Individuals affected by Broca’s aphasia are able to speak only with great difficulty.
Feedback: Speech is controlled from the left hemisphere in the majority of left handed people. In Broca’s aphasia speech is slow, halting and telegraphic in quality but affected individuals do not have paralysis of the lips and tongue. Wernicke’s aphasia (receptive aphasia) is the result of lesions to the left temporal lobe adjacent to the primary auditory cortex.
6. Regarding the functions of the cerebral hemispheres
a) The parietal lobes are involved in pain perception.
b) Damage to the parietal lobes is associated with paralysis of the muscles on the contralateral side of the body.
c) Damage to the temporal lobes can lead to a failure of object recognition.
d) The parietal lobe on the right side of the brain plays a significant role in the comprehension of speech.
(d) The parietal lobe on the right side of the brain plays a significant role in the comprehension of speech.
Feedback: The parietal lobes play no specific role in the perception of pain. Pain perception is associated with the SII region of the cortex and with the frontal lobes. Damage to the parietal lobes may result in apraxia, an inability to perform a specific motor task, but there is no paralysis of the skeletal muscles. Damage to the temporal lobes may cause loss of memory. Damage to the parietal lobes is associated with agnosia (failure of object recognition). The parietal lobes play an important role in the interpretation of speech, particularly its emotional content.
7. Which of the following statements about the nervous system are true? [Select all that apply]
a) Each cerebral hemisphere is divided into two lobes.
b) Each spinal segment gives rise to four spinal nerves.
c) The dorsal root ganglia contain the cell bodies of the primary sensory neurons
d) The white and grey matter of the spinal cord is arranged in the same way as that of the cerebral hemispheres.
e) Grey matter contains the cell bodies and dendrites of neurons
(c) The dorsal root ganglia contain the cell bodies of the primary sensory neurons
(e) Grey matter contains the cell bodies and dendrites of neurons.
Feedback: Each cerebral hemisphere is divided into four lobes: the frontal, parietal, occipital and temporal lobes. Each spinal segment gives rise to four spinal roots (two dorsal and two ventral roots) but the dorsal and ventral roots fuse to form the spinal nerves. Therefore each segment gives rise to a pair of spinal nerves. In the cerebral hemispheres the grey matter lies on the outside with the white matter beneath. In the spinal cord the grey matter forms the central butterfly shaped region and is surrounded by white matter.
8. Which of the following statements about the central nervous system (CNS) are correct? ]Select all that apply]
a) The capillaries of the brain are covered by the end feet of oligodendrocytes
b) The extracellular fluid surrounding nerve cells is insulated from changes in the composition of the plasma.
c) The cerebrospinal fluid (CSF) is an ultrafiltrate of plasma
d) The CSF is secreted by the choroid plexuses of the cerebral ventricles
(b) The extracellular fluid surrounding nerve cells is insulated from changes in the composition of the plasma.
(d) The CSF is secreted by the choroid plexuses of the cerebral ventricles
Feedback: The end feet of the astrocytes form part of the blood brain barrier that isolates the extracellular fluid around the neurons from changes in the composition of the blood. The CSF is not an ultrafiltrate of plasma but is secreted by the choroid plexus.
9. Which of the following statements about the central nervous system (CNS) is correct?
a) White matter contains many nerve cell bodies
b) The myelin sheaths are formed by Schwann cells
c) There are twelve pairs of cranial nerves
(c) There are twelve pairs of cranial nerves
Feedback: In the CNS the majority of nerve cell bodies are found in the grey matter. The myelin sheath of CNS axons is formed by oligodendrocytes.
10. Intracranial pressure tends to rise when
A. Cerebral venous pressure rises.
B. Forced expiration is made against a closed glottis.
C. There is a bout of coughing.
D. Cerebral blood flow increases.
E. Arterial PCO2 falls below normal.
11. Characteristic features of cerebellar disease include loss of
A. Muscle tone
B. Muscle strength
C. Conscious muscle-joint sense
D. Ability to make precise muscle movements
E. Ability to fix the gaze steadily on an object
12. Signs of brainstem death include
B. Loss of pupillary reaction to light
C. Loss of tendon jerks in the arms and legs
D. Loss of respiratory response to CO2 in the absence of hypoxia.
E. Nystagmus in response to cold water in the external auditory canal
13. Delta (δ) wave activity in the electroencephalogram
A. Is low in frequency and amplitude.
B. Suggests that the patient is alert and concentrating.
C. When unilateral suggests a brain abnormality.
D. Is a feature of petit mal epilepsy.
E. Is more common in children than in adults while they are awake.
14. Increased intracranial pressure may cause
A. Cranial enlargement in children
B. Squinting and loss of smell sensation in children.
C. Cupping of the optic disc
D. An increase in cerebral blood flow
E. Arterial hypertension
15. In the cerebral cortex
A. Neuronal connections are innate and immutable.
B. Language and non-language skills are represented in different hemispheres.
C. The areas concerned with emotional behavior are concentrated in the frontal lobes.
D. The cortical area devoted to sensation in the hand is larger than that for the trunk.
E. Stimulation of the motor cortex causes contractions of individual muscles on the opposite side of the body.