DR.
MOHAMED ELSHERIF
PHYSIOLOGY MCQS
Sensory Nervous System
Choose the correct answer:
❶ The central nervous system is connected with the peripheral NS by all the following types of
nerve fibers, except:
A. postganglionic autonomic fibers.
B. preganglionic autonomic fibers.
C. somatic motor fibers.
D. autonomic sensory fibers.
❷ Regarding inhibitory synaptic transmission mechanism, all statements are correct EXCEPT:
A. are always postsynaptic.
B. may depolarize the presynaptic membrane.
C. may involve a postsynaptic increase in Cl- conductance.
D. tends to decrease the frequency of action potentials in the post synaptic nerve.
❸ Regarding presynaptic inhibition:
A. the postsynaptic neurone membrane is hyperpolarized.
B. there is a decrease in the release of chemical transmitters from the presynaptic
neurone.
C. there is increased Ca2+ influx into the presynaptic neurone.
D. there is closure of K+ channels of the presynaptic neurone.
❹ The release of neurotransmitter at a chemical synapse in the central nervous system is
dependent upon which of the following?
A. synthesis of acetylcholinesterase.
B. hyperpolarization of the synaptic terminal.
C. opening of ligand-gated ion calcium channels.
D. influx of calcium into the presynaptic terminal.
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PHYSIOLOGY MCQS
❺ The excitatory or inhibitory action of a neurotransmitter is determined by which of the
following?
A. function of its postsynaptic receptor.
B. molecular composition.
C. shape of the synaptic vesicle in which it is contained.
D. distance between the pre- and post-synaptic membranes.
❻ Regarding synapses:
A. presynaptic knobs contain vesicles which have t-snare in their membranes.
B. V-snare of the vesicles has high affinity to t-snare in the active zone of the
presynaptic membrane.
C. Ca2+ voltage gated channels of the pre-synaptic knob open during
repolarization.
D. synaptic cleft contain high concentration of K+.
❼ Excitatory postsynaptic potential:
A. cannot be summated.
B. is a state of local depolarization.
C. is due to opening of voltage gated Na+ channels.
D. is due to opening of chemical gated K+ channels.
❽ Grand post-synaptic potential, may cause the postsynaptic membrane to:
A. be more excitable if EPSP > IPSP.
B. be less excitable if IPSP > EPSP.
C. reach firing if there is summation of EPSPs.
D. all of the above.
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PHYSIOLOGY MCQS
❾ Presynaptic inhibition is characterized by:
A. decreased Cl- influx into presynaptic terminals.
B. hyperpolarization of presynaptic terminals.
C. increased Ca2+ influx into post-synaptic neuron.
D. a 3rd neuron secreting serotonin.
❿ Synaptic transmission is terminated by which of the following?
A. block of postsynaptic receptors.
B. elevation of Ca++ in presynaptic knobs.
C. reuptake of neurotransmitters by postsynaptic neurons.
D. degradation of neurotransmitters by specific enzymes.
⓫ Regarding synapses:
A. synaptic cleft contain high K+ concentration.
B. Ca++ voltage gated channels of the presynaptic knobs open during repolarization.
C. extracellular Ca++ concentration equals that of intracellular.
D. presynaptic knobs contain vesicles with V-Snare proteins in their membranes.
⓬ Excitatory postsynaptic potential:
A. shows reversal of polarity.
B. obeys all or none rule.
C. cannot be propagated.
D. cannot be summated.
⓭ The excitatory postsynaptic potential (EPSP) is:
A. produced as a result of release of GABA.
B. a state of partial depolarization.
C. due to increased permeability to Cl- in the postsynaptic membrane.
D. unable to undergo summation.
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PHYSIOLOGY MCQS
⓮ lonotropic receptors:
A. act by changing levels of intracellular CAMP.
B. are ligand gated ion channels.
C. act by increasing intracellular IP3.
D. are voltage gated ion channels.
⓯ The inhibitory postsynaptic potential (IPSP) is:
A. produced as a result of release of acetyl choline.
B. involved in the gate theory of pain control.
C. a state of hyperpolarization.
D. due to increased Na+ permeability in the postsynaptic membrane.
⓰ IPSP differs from EPSP in:
A. being of short duration.
B. being unable to summate.
C. moving the postsynaptic membrane potential away from threshold.
D. being propagated at same rate as action potential.
⓱ Presynaptic inhibition:
A. produced as a result of release of GABA.
B. leads to decreased release of neurotransmitter.
C. is involved in the gate theory of pain control.
D. all of the above.
⓲ Excitatory presynaptic potential:
A. needs excitatory 3rd neuron.
B. needs inhibitory 3rd neuron.
C. leads to hyperpolarization of presynaptic membrane.
D. directly excites the postsynaptic membrane.
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PHYSIOLOGY MCQS
⓳ Temporal summation:
A. occurs by rapid repetitive stimuli originating from one presynaptic neuron.
B. occurs by rapid repetitive stimuli originating from many presynaptic neurons.
C. occurs by multiple stimuli originating from one presynaptic neuron.
D. occurs by multiple stimuli originating from many presynaptic neurons.
⓴ Synaptic transmission is stimulated by:
A. hypercalcemia. B. alkalosis. C. acidosis. D. botulism.
21 Synaptic depression may result from all of the following EXCEPT:
⓭
A. botulin. B. hypoxia. C. acidosis. D. strychnine.
⓭
22 Tetanus toxin leads to:
A. spastic paralysis due to inhibition of acetyl choline release.
B. convulsions due to competitive inhibition with inhibitory transmitters.
C. flaccid paralysis due to inhibition of GABA release.
D. spastic paralysis due to inhibition of GABA release.
23 Habituation of synapses:
⓭
A. is due to decrease release of neurotransmitters from the presynaptic neuron.
B. is due to nocious stimuli.
C. is due to increase Ca2+ influx in presynaptic neuron.
D. a & c are correct.
24 Post-tetanic potentiation is due to:
⓭
A. rapid active Ca2+ pump out of the presynaptic neuron.
B. repetitive stimulation of the presynaptic neuron not to the extent to produce
fatigue.
C. is due to nocious stimuli.
D. repetitive benign stimuli at intervals.
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PHYSIOLOGY MCQS
25 Habituation is:
⓭
A. persistent decrease in synaptic strength after weak intensity stimuli.
B. continuous discharge from postsynaptic neuron after brief tetanizing stimuli.
C. gradual loss of response to repeated benign neutral stimuli.
D. augmented response to repeated benign neutral stimuli.
26 Habituation of synapses:
⓭
A. is due to excess release of neurotransmitters from the presynaptic neuron.
B. is due to noxious stimuli.
C. is due to increase Ca2+ influx in presynaptic neurone.
D. is due to a gradual decrease of response of the postsynaptic membrane due to
inactivation of calcium channels in presynaptic neurons.
27 Sensitization of synapses:
⓭
A. is due to decreased release of neurotransmitter from presynaptic neuron.
B. causes hyperpolarization of postsynaptic neuron.
C. is explained by presynaptic facilitation.
D. is due to accumulation of Ca++ in presynaptic knob.
28 Divergence:
⓭
A. helps amplification of the signal.
B. means that several input fibres supply a single neuron.
C. helps the process of summation.
D. explains the process of occlusion.
29 Regarding the excitation field:
⓭
A. neurons in the periphery receive large number of knobs.
B. are of the discharge zone is in the periphery.
C. neurons in the centre receive large number of knobs.
D. neurons in the periphery are inhibited.
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PHYSIOLOGY MCQS
30 Renshaw cell:
⓭
A. is activated by glycine.
B. shows the phenomenon of negative feedback inhibition.
C. is present in dorsal horn of the spinal cord.
D. are excitatory neurons.
31 Occlusion:
⓭
A. occurs due to overlap of facilitation zones of two adjacent neuronal pools.
B. occurs due to overlap of discharge zones of two adjacent neuronal pools.
C. increases the combined effect of two adjacent neurons when stimulated
simultaneously.
D. is continued output discharge after stoppage of stimulation of input.
32 Lateral inhibition:
⓭
A. helps sharpening of sensation.
B. needs only inhibitory neurons.
C. occurs by inhibition of a central neuron and exciting the surrounding neurons.
D. occurs by one type of chemical transmitter.
33 Neuropeptides:
⓭
A. are synthesized in the presynaptic knobs.
B. are synthesized in the soma of the neuron.
C. consist of small molecules.
D. are rapidly acting.
34 All the following transmitters are neuropeptides except:
⓭
A. neuropeptide Y.
B. somatostatin.
C. dopamine.
D. enkephalin.
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PHYSIOLOGY MCQS
35 Receptor potential:
⓭
A. is actively conducted to the 1st node of Ranvier.
B. has a duration shorter than that of the action potential.
C. amplitude is proportional to the intensity of the stimulus.
D. is due to specific increase of the membrane permeability to Na+ ions.
36 Tonic receptors include all of the following, Except:
⓭
A. touch receptors.
B. nociceptors.
C. barorecptors.
D. muscle spindles.
37 As regards the Properties of the receptor potential:
⓭
A. it is actively conducted to the 1st node of Ranvier.
B. its duration is 0.5 msec.
C. it is accompanied by absolute refractory period.
D. it does not obey the all or non rule.
38 Receptor potential initiated by an adequate stimulus:
⓭
A. develops always at it full magnitudes.
B. undergoes temporal summation only.
C. undergoes spatial summation only.
D. could initiate an action potential.
39 Slowly adapting receptors include all the following types, Except:
⓭
A. proprioceptors.
B. lung stretch receptors.
C. nociceptors.
D. touch receptors.
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PHYSIOLOGY MCQS
40 Detection of the stimulus modality depends upon:
⓭
A. the location of the receptors in the body.
B. the magnitude of the stimulus.
C. the anatomical connections between the receptors and specific sensory areas in
the cerebral cortex.
D. the magnitude of the receptor potential.
41 Sensory receptors:
⓭
A. produce all or none - receptor potential.
B. typically respond to a broad range of stimuli.
C. code for stimulus strength by changes in receptor potential amplitude.
D. code for stimulus strength by frequency of the receptor potential.
42 The lateral spinothalamic tract is characterized by all of the following, EXCEPT:
⓭
A. carries fibres which terminate in the thalamus.
B. contains mainly the second-order neurones.
C. carries fibres that carry information on temperature and pain.
D. contains nerve fibres from receptors on the ipsilateral side of the body.
43 The following sensations are transmitted in the dorsal column of the spinal cord, EXCEPT:
⓭
A. temperature.
B. vibration.
C. proprioception.
D. joint position.
44 Tactile receptors include the following receptors:
⓭
A. krause receptors.
B. hair follicle receptors.
C. hair cell receptors.
D. muscle spindle.
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PHYSIOLOGY MCQS
45 Fine touch is:
⓭
A. detected by slowly adapting touch receptors.
B. transmitted by the ventral spinothalamic tract.
C. tested by piece of cotton.
D. not involved in feeling the texture of touched objects.
46 A more developed two-point tactile discrimination:
⓭
A. indicates a greater threshold distance for feeling of two points of touch applied
simultaneously.
B. is seen in the proximal regions of the limbs compared with the distal regions.
C. is inversely related to the size of the receptive fields of the stimulated sensory
units.
D. depends upon the type of the involved touch receptor.
47 Proprioceptive sensations include all the following, EXCEPT:
⓭
A. position sense. B. equilibrium sense.
C. movement sense.
D. vibration sense.
48 Proprioceptors include all the following types of receptors, EXCEPT:
⓭
A. muscle receptors.
B. pressure receptors.
C. vestibular receptors.
D. joint receptors.
49 Proprioceptive sensations are transmitted by all the following pathways, except:
⓭
A. spinothalamic tracts.
B. spinocerebellar tract.
C. gracile tract.
D. cuneate tract.
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PHYSIOLOGY MCQS
50 Proprioceptive sensations include all the following, except:
⓭
A. static position sense.
B. afferent neurons of Aβ fibers.
C. rate of movement.
D. afferent neurons of Aα fibers.
51 Vibration sense:
⓭
A. is sensed by free nerve endings.
B. depends on past cortical experience.
C. is carried on dorsal column.
D. is carried on spinothalamic tract.
52 Pain produced by tissue damage is due to release of:
⓭
A. excess norepinephrine.
B. ATP.
C. bradykinins.
D. b & c are correct.
53 Individuals complaining of severe pain have difficulty in sleeping due to:
⓭
A. neurotransmitters released in the pain pathway diffuse into the neighboring cells
and block the sleep circuits.
B. neurotransmitters released in the pain pathway diffuse into neighboring neurons
and raise the excitability of the brain.
C. ascending pain pathway excites the reticular formation involved in the
maintenance of waking state.
D. the somatic sensory cortex for pain perception block the sleep circuits.
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PHYSIOLOGY MCQS
54 Dull aching pain is:
⓭
A. carried along type A delta fibres.
B. mediated via type C fibres.
C. rapidly felt.
D. sensed by encapsulated nerve endings.
55 The analgesia system includes:
⓭
A. raphe magnus nucleus in the post horn of the spinal cord.
B. the periaquiductal area in the mid-brain.
C. the sensory area I.
D. supra-optic nuclei of the hypothalamus.
56 Action potentials recorded after stimulation of thermal receptors show that:
⓭
A. the maximal rate of discharge of action potentials in the cold nerve fibers is at
25°c.
B. action potentials recorded in warm nerve fibers between 10 -35°c.
C. action potentials are recorded in cold pain fibers at 0 °c.
D. the maximum rate of discharge from warm pain and cold pain fibers occurs at 40°c.
57 Pain receptors are:
⓭
A. quick to adapt to a constant stimulus.
B. more easily stimulated in injured tissue.
C. similar to structure of Pacinian corpuscles.
D. stimulated in the gut wall by cutting stimuli.
58 Fast pain differs from slow pain in:
⓭
A. being transmitted in the dorsal column pathway.
B. evoking a reflex spasm of the muscles.
C. having a sharp quality.
D. arising from encapsulated pain receptors.
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PHYSIOLOGY MCQS
59 Cutaneous pain is:
⓭
A. sharp in character.
B. transmitted by A-gamma sensory fibers.
C. always followed by hyperalgesia.
D. transmitted along ventral spinocerebellar tracts.
60 Cutaneous pain is:
⓭
A. only sharp in character.
B. transmitted by Aδ sensory fibers.
C. always followed by hyperalgesia.
D. transmitted along ventral spinocerebellar tracts.
61 Intermittent Claudications evoke:
⓭
A. visceral pain.
B. deep pain.
C. cutaneous hyperalgesia.
D. colicky pain.
62 Visceral pain signals are:
⓭
A. transmitted along sensory fibers that travel mainly with autonomic nerves in
abdomen and thorax.
B. not stimulated by ischemia in visceral organs.
C. transmitted only by the myelinated type A delta sensory fibers.
D. typically well localized.
63 Visceral pain:
⓭
A. is more common than the other types of pain.
B. arises only from wall of the visceral organs.
C. is often well localized.
D. evokes depressor autonomic reactions.
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PHYSIOLOGY MCQS
64 Visceral pain is usually felt:
⓭
A. deeply in the diseased viscera.
B. in deep tissues close to the diseased viscera.
C. in skin areas that just overlie the diseased viscera.
D. in skin areas which has the same dorsal root as the diseased viscera.
65 Transmitters in pain control system include all the following, EXCEPT:
⓭
A. serotonin.
B. acetylcholine.
C. enkephalin.
D. beta endorphin.
66 Intracranial headache could result from injurious stimuli on EXCEPT:
⓭
A. the dura lining the brain.
B. the brain tissue.
C. wall of the big intracranial veins.
D. middle meningeal artery.
67 Extracranial headache may be produced by:
⓭
A. sinusitis.
B. errors of refraction.
C. sustained contraction of the neck muscles.
D. all of the above.
68 All of the following are cause of intracranial headache, EXCEPT:
⓭
A. alcohol intoxication.
B. inflammation of nasal sinuses.
C. brain tumors.
D. dilatation of the cerebral arteries.
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PHYSIOLOGY MCQS
69 An inter-neuron in which region uses Enkephalin to inhibit pain transmission:
⓭
A. post - central gyrus.
B. raphe magnus nucleus.
C. dorsal horn of spinal cord.
D. periaqueductal gray area.
70 A patient had destruction of somatic sensory area l on the left side will show:
⓭
A. total lack of pain sensation on the same side.
B. total lack of temperature sensation of the same side.
C. inability to identify objects put in the right hand.
D. inability to identify objects put in the left hand.
71 After anterolateral cordotomy, relief of pain is due to interruption of:
⓭
A. dorsal column.
B. lateral spinothalamic tract.
C. ventral spinothalamic tract.
D. ventral spinocerebellar tract.
72 Astereognosis:
⓭
A. indicates inability to localize the site of touch on the body surface.
B. results from lesions of the somatic sensory area l & associated sensory area.
C. associates parietal lobe neglect.
D. results from loss of crude touch sensation.
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PHYSIOLOGY MCQS
Answer Key
1 A 11 D 21 D 31 B 41 C 51 C 61 B 71 B
2 C 12 C 22 D 32 A 42 D 52 D 62 A 72 B
3 B 13 B 23 A 33 B 43 A 53 C 63 D
4 D 14 B 24 B 34 C 44 B 54 B 64 D
5 A 15 C 25 C 35 C 45 A 55 B 65 B
6 B 16 C 26 D 36 A 46 C 56 A 66 B
7 B 17 D 27 C 37 D 47 B 57 B 67 D
8 D 18 A 28 A 38 D 48 C 58 C 68 B
9 B 19 A 29 C 39 D 49 A 59 A 69 C
10 D 20 B 30 B 40 C 50 B 60 B 70 C
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