[MCQ] Biology of Neurologic Diseases- Part 1

I. Start the exam by click the “Start” button

See all quizzes of Porphyrias at here:

Biology of Neurologic Diseases- Part 1| Biology of Neurologic Diseases- Part 2|Biology of Neurologic Diseases- Part 3

1 What proportion of 23,000 genes encoded in human genome are
expressed in human nervous system ?
A. ~ one-fourth
B. ~ one-third
C. ~ one-half
D. ~ three-fourth

2 Each mature brain is composed of how many neurons ?
A. 10 million
B. 100 million
C. 10 billion
D. 100 billion
3 Each mature brain is composed of how many synapses ?
A. ~ 1010
B. ~ 1015
C. ~ 1020
D. ~ 1025

4 Which of the following is a monogenic disorder ?
A. Familial Alzheimer’s disease
B. Frontotemporal dementia
C. Parkinson’s disease
D. All of the above

5 Nissl bodies are composed of ?
A. Mitochondria
B. Endoplasmic reticulum
C. Golgi complex
D. Lysosomes
6 Synaptic glomeruli are found in ?
A. Cerebellum
B. Olfactory bulb
C. Lateral geniculate body
D. All of the above
7 What fraction of genes encoded in human genome is expressed in
the nervous system ?
A. One-third
B. One-half
C. Two-third
D. Three-fourth
8 Tone is the resistance of a muscle to ?
A. Active stretch
B. Passive stretch
C. Gravitational stretch
D. Anti-gravity stretch

9 Increased muscle tone is found in ?
A. Spasticity
B. Rigidity
C. Paratonia
D. All of the above
10 Which of the following about ‘Spasticity’ is false ?
A. Velocity-dependent
B. Sudden release at maximum
C. Affects antigravity muscles
D. None of the above

11 Which of the following about ‘Rigidity’ is false ?
A. Present throughout range of motion
B. Affects flexors & extensors equally
C. Occurs with extrapyramidal disorders
D. None of the above

12 Which of the following about ‘Paratonia’ is false ?
A. Also called gegenhalten
B. Increased tone varies irregularly
C. Present throughout range of motion
D. None of the above
13 Which of the following about ‘Paratonia’ is false ?
A. Increased muscle tone
B. Affects flexors & extensors equally
C. Results from disease of frontal lobes
D. None of the above

14 Which of the following about ‘flaccidity’ is false ?
A. Weakness
B. Decreased tone
C. Disorder of motor unit
D. None of the above

15 Which of the following is false about fasciculation ?
A. Visible twitch
B. Palpable twitch
C. Spontaneous discharge of a motor unit
D. None of the above

16 Which of the following is false about upper motor neuron
weakness ?
A. Proximal muscle groups affected more than distal
B. Axial movements spared
C. Affects ability to perform rapid repetitive movements
D. Normal movement rhythmicity is maintained

17 Upper motor neurons have their cell bodies in which layer of
primary motor cortex ?
A. Layer III
B. Layer IV
C. Layer V
D. Layer VI

18 What proportion of pyramidal axons do not decussate and remain
ipsilateral ?
A. 2 to 10 %
B. 5 to 15 %
C. 10 to 30 %
D. 20 to 35 %

19 Pyramidal axons innervate most densely which of the following
lower motor neurons ?
A. Of hand muscles
B. Of foot muscles
C. Of axial muscles
D. Of face muscles

20 Descending ventromedial bulbospinal pathways include ?
A. Tectospinal pathway
B. Vestibulospinal pathway
C. Reticulospinal pathway
D. All of the above

21 All of the following are part of descending ventromedial
bulbospinal pathways except ?
A. Tectospinal pathway
B. Vestibulospinal pathway
C. Reticulospinal pathway
D. Rubrospinal pathway

22 Which of the following is false about lower motor neuron weakness ?
A. Due to loss of  neurons
B. Due to loss of  motor neurons
C. Absent tendon stretch reflex suggests involvement of spindle
afferent fibers
D. Fasciculations signify anterior horn cell disease
Loss of -motor neurons does not cause weakness but decreases muscle tone and attenuates the
stretch reflexes elicited on examination.
23 Which of the following is false about motor neurons ?
A. motor neurons innervate extrafusal muscle fibers
B. motor neurons innervate intrafusal muscle fibers
C.  motor neuron receives direct excitatory input from
corticomotoneurons & primary muscle spindle afferents
D.  motor neurons receive direct excitation from Renshaw cell
interneurons
-motor neurons receive direct inhibition from Renshaw cell interneurons.
24 Which of the following is false about myopathic weakness ?
A. Due to disorders of muscle fibers
B. Due to defect in neuromuscular junctions
C. In EMG, size of each motor unit action potential is reduced
D. Distribution of weakness is distal
Distribution of myopathic weakness is typically proximal. Lower motor neuron weakness is most
profound distally.
25 “Pure motor” hemiparesis of the face, arm, or leg is due to a
lesion in ?
A. Posterior limb of internal capsule
B. Cerebral peduncle
C. Upper pons
D. Any of the above