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Chapter: Nervous System
| 1. | Regarding muscle spindles: |
| A. | are composed of extrafusal fibres |
| B. | receive δ efferents |
| C. | all subtypes send afferents via “flower spray” ended 1a nerves |
| D. | nuclear chain fibres show dynamic response |
| E. | afferent discharge decreased with muscle stretch |
| Answer» B. receive δ efferents | |
discuss
| 2. | Regarding the dorsal column: |
| A. | carries ipsilateral pain and temperature |
| B. | ascends to the nuclei gracillis and ????? |
| C. | receives efferents from contralateral stimuli |
| D. | sacral efferents lie laterally |
| E. | runs anteriorly in the cord |
| Answer» B. ascends to the nuclei gracillis and ????? | |
discuss
| 3. | Temperature sensation: |
| A. | respond to compartitive temp gradient ??? skin |
| B. | cold receptors predominate |
| C. | warm receptors respond 30° - 100° |
| D. | afferents carried via the dorsal column |
| E. | warm and cold afferents carried via Ad fibre |
| Answer» B. cold receptors predominate | |
discuss
| 4. | Regarding visual receptors: |
| A. | rods predominate in the jovea |
| B. | rhodopsin is the primary pigment of rods |
| C. | lie anterior (superficial) to their neural pathway |
| D. | colour blindness is an autosomal recessive gene |
| E. | supplied by retinal vessels |
| Answer» B. rhodopsin is the primary pigment of rods | |
discuss
| 5. | Regarding sound and hearing: |
| A. | high pitched sounds are detected at the apex of the cochlear |
| B. | Harr cells are bathed in endolymph |
| C. | defected by hair cells found within the tectorium membrane |
| D. | 95% of afferent neurones → outer ??? cells |
| E. | supplied by retinal vessels |
| Answer» E. supplied by retinal vessels | |
discuss
| 6. | Regarding noradrenergic stimulation: |
| A. | miosis occurs |
| B. | increases blood flow to the skin |
| C. | increases thresholds in the reticular formation |
| D. | causes erection in males |
| E. | elevates free fatty acid levels |
| Answer» D. causes erection in males | |
discuss
| 7. | Regarding cholinergic stimulation: |
| A. | causes amylase secretion from salivary glands |
| B. | decreases secretion from pancreatic ????? |
| C. | relaxes the gallbladder |
| D. | has no effect on renal arterioles |
| E. | relaxes bronchial smooth muscle |
| Answer» D. has no effect on renal arterioles | |
discuss
| 8. | The emotional component to pain is due to activation of: |
| A. | post central gyrus |
| B. | sylvian fissure |
| C. | hippocampus |
| D. | cingulated cortex |
| E. | calcavine fissure |
| Answer» A. post central gyrus | |
discuss
| 9. | The chemical agent that initiates impulses in pain fibres is: |
| A. | ATP |
| B. | substance P |
| C. | Ca2+ |
| D. | H+ |
| E. | K+ |
| Answer» B. substance P | |
discuss
| 10. | Regarding thermoceptors: |
| A. | there are more warm receptors than cold receptors |
| B. | cold receptors respond to 10-38°C |
| C. | afferents for cold receptors are C fibres only |
| D. | afferents found in the ventral spinothalamic tract |
| E. | respond to the temperature gradient across the skin |
| Answer» C. afferents for cold receptors are C fibres only | |
discuss
| 11. | Regarding body temperature: |
| A. | humans are poikilothermic |
| B. | oral temperature is usually higher than rectal temperature |
| C. | it is usually lowest at 6am |
| D. | children have more precise temperature regulation |
| E. | emotion has no effect on core temperature |
| Answer» E. emotion has no effect on core temperature | |
discuss
| 12. | Regarding the hypothalamus: |
| A. | it has neural connections with the anterior pituitary gland |
| B. | it integrates the vomiting reflex |
| C. | the anterior hypothalamus responds to cold |
| D. | it controls circadian rhythms via the supraoptic nuclei |
| E. | it has osmoreceptors in the anterior hypothalamus to stimulate thirst and vasopressin release |
| Answer» B. it integrates the vomiting reflex | |
discuss
| 13. | Regarding the vomiting reflex, which is INCORRECT? |
| A. | it is integrated by the medilla |
| B. | breath is held in expiration |
| C. | the glottis closes |
| D. | it involves salivation |
| E. | there are afferents from vestibular nuclei |
| Answer» B. breath is held in expiration | |
discuss
| 14. | Herring bodies are: |
| A. | nuclei of the hypothalamus |
| B. | secretory granules in the posterior pituitary |
| C. | circumventricular organs |
| D. | neurons connecting vestibular nuclei with the vomiting centre |
| E. | vesicles containing ACTH, TSH, GH, FSH, CH and PRL |
| Answer» C. circumventricular organs | |
discuss
| 15. | The neurotransmitter secreted by primary afferent fibres for severe pain is: |
| A. | glutamate |
| B. | acetylcholine |
| C. | substance P |
| D. | opioid peptides |
| E. | noradrenaline |
| Answer» D. opioid peptides | |
discuss
| 16. | Regarding rods and cones: |
| A. | Na+ channels are closed in the dark |
| B. | light striking the outer segments results in a depolarising receptor potential |
| C. | the receptor potentials are all-or-nothing |
| D. | rhodopsin is a serpentine receptor |
| E. | acetylcholine is released from the synaptic terminal |
| Answer» C. the receptor potentials are all-or-nothing | |
discuss
| 17. | The visual cortex is situated at the: |
| A. | parieto-occipital sulcus |
| B. | cuneus |
| C. | calcanine fissure |
| D. | lateral geniculate body |
| E. | angular gyrus |
| Answer» D. lateral geniculate body | |
discuss
| 18. | In the visual pathway: |
| A. | the lateral geniculate bodies are made up of t layers |
| B. | fibres for reflex pupillary constriction leave the optic nerve at the optic chiasm |
| C. | pituitary tumours can cause hom*onymous hemianopia |
| D. | macular sparing may or may not occur with lesions in the geniculocalcanine tract |
| E. | binasal visual field fibres decussate at the opticchiasm |
| Answer» D. macular sparing may or may not occur with lesions in the geniculocalcanine tract | |
discuss
| 19. | When a normal innervated skeletal muscle is stretched, the initial response is contraction, but with increasing stretch, the muscle suddenly relaxes because: |
| A. | with strong stretch, the efferent discharge is decreased |
| B. | with strong stretch, the discharge from the annulospiral endings of afferent nerve fibres is inhibited |
| C. | with strong stretch, there is decreased activity in the afferent nerve fibres from the Golgi tendon organs |
| D. | with strong stretch, there is increased activity in the afferent nerve fibres from the Golgi tendon organs |
| E. | because of reciprocal innervation, there is increased discharge in the afferent nerve fibres from the antagonists to the stretched muscle |
| Answer» E. because of reciprocal innervation, there is increased discharge in the afferent nerve fibres from the antagonists to the stretched muscle | |
discuss
| 20. | In a polysynaptic reflex, which of the following happen when the strength of the adequate stimulus is increased? |
| A. | the amplitude of the motor response is increased |
| B. | the motor response spreads to include other muscles and even other limbs |
| C. | there is increased inhibition of stretch reflexes |
| D. | the duration of the motor response increases |
| E. | all of the above are true |
| Answer» A. the amplitude of the motor response is increased | |
discuss
| 21. | A tumour causing external compression to the anterior cervical spinal cord would beexpected to: |
| A. | impair pressure and pain sensation mostly from sacral and lumbar areas |
| B. | impair fine touch and vibration mostly from sacral and lumbar areas |
| C. | impair pain only from cervical areas |
| D. | impair vibration sense only from cervical areas |
| E. | impair joint position from sacral areas only |
| Answer» D. impair vibration sense only from cervical areas | |
discuss
| 22. | Which of the following need to be intact for normal stereognosis: |
| A. | dorsal columns |
| B. | parietal lobe |
| C. | pressure pathways |
| D. | all of the above |
| E. | none of the above |
| Answer» B. parietal lobe | |
discuss
| 23. | Bitemporal hemianopia is most likely to be caused by a lesion at the: |
| A. | optic nerve |
| B. | optic chiasm |
| C. | optic tract |
| D. | optic radiation |
| E. | visual cortex |
| Answer» D. optic radiation | |
discuss
See Also
[Solved] Nervous System MCQ [Free PDF] - Objective Question Answer for Nervous System Quiz - Download Now![Solved] Peripheral and Autonomic Nervous System MCQ [Free PDF] - Objective Question Answer for Peripheral and Autonomic Nervous System Quiz - Download Now![Solved] Nervous system MCQ [Free PDF] - Objective Question Answer for Nervous system Quiz - Download Now!Central Nervous System (CNS) Solved MCQs with PDF Download| 24. | Regarding temperature regulation, which is NOT true? |
| A. | the anterior hypothalamus contains temperature sensitive cells |
| B. | shivering is activated by the posterior hypothalamus |
| C. | the anterior hypothalamus controls mechanisms activated by heat |
| D. | horripilation acts to increase heat production |
| E. | fever is produced by the action of cytokines on the hypothalmus |
| Answer» E. fever is produced by the action of cytokines on the hypothalmus | |
discuss
| 25. | When a visual stimulus falls on a given point in the retina for a long time: |
| A. | the image becomes more clearly focused |
| B. | there is adaptation in the visual cortex |
| C. | the discharge rate in the bipolar cells increases |
| D. | the pupils constrict |
| E. | the image fades and disappears |
| Answer» A. the image becomes more clearly focused | |
discuss
| 26. | Which of the following affect visual activity? |
| A. | cataracts |
| B. | vitamin A deficiency |
| C. | astigmatism |
| D. | contrast between stimulus and background |
| E. | all of the above |
| Answer» E. all of the above | |
discuss
| 27. | The ‘tympanic reflex’: |
| A. | is activated by foreign bodies in the external auditory canal |
| B. | results in vertigo |
| C. | is activated by high-pitched sounds only |
| D. | results in the decreased transmission of sound |
| E. | none of the above |
| Answer» D. results in the decreased transmission of sound | |
discuss
| 28. | Regarding pain transmission, which is NOT true? |
| A. | ‘fast pain’ fibres are Aδ fibres |
| B. | ‘slow pain’ fibres are C fibres |
| C. | substance P is the central transmitter |
| D. | all impulses pass through the central horn |
| E. | pain sensation results from over-stimulation of other sensory modalities |
| Answer» E. pain sensation results from over-stimulation of other sensory modalities | |
discuss
| 29. | Which is NOT a part of the basal ganglia? |
| A. | caudate nucleus |
| B. | cuneate nucleus |
| C. | substantia nigra |
| D. | putamen |
| E. | globus pallidum |
| Answer» B. cuneate nucleus | |
discuss
| 30. | With regard to pain pathways, all the following are true EXCEPT: |
| A. | peripheral afferents are transmitted along A (delta) and C fibres |
| B. | an intact cerebral cortex is necessary for pain sensation |
| C. | the synaptic transmitter released by primary afferent fibres subserving pain is substance P |
| D. | afferent fibres subserving pain sensation from viscera reach the CNS by both sympathetic and parasympathetic pathways |
| E. | the sensory organs for pain are marked nerve endings |
| Answer» B. an intact cerebral cortex is necessary for pain sensation | |
discuss
| 31. | Cerebellar disease in humans causes all of the following EXCEPT: |
| A. | dysmetria |
| B. | scanning speech |
| C. | lead pipe rigidity |
| D. | rebound phenomenon |
| E. | dysdiadockokinesia |
| Answer» C. lead pipe rigidity | |
discuss
| 32. | The righting reflex is pronounced after sectioning of the neural axis above whichlevel: |
| A. | spinal cord |
| B. | medulla |
| C. | mid-brain |
| D. | subcortical nuclei |
| E. | all above intact but decerebellate |
| Answer» C. mid-brain | |
discuss
| 33. | Regarding muscle spindles, which is NOT true? |
| A. | they contain nuclear bag and nuclear chain fibres |
| B. | they receive a motor supply via Aγ fibres |
| C. | they discharge more upon stretching of the muscle |
| D. | they are responsible for the inverse stretch reflex |
| E. | they relay information to the cord via Ia fibres |
| Answer» D. they are responsible for the inverse stretch reflex | |
discuss
| 34. | The action potential of a neuron (influx): |
| A. | is initiated by efflux of Na+ |
| B. | is terminated by efflux of K+ |
| C. | declines in amplitude as it moves along the axon |
| D. | results in transient reversal of the concentration (?electrical) gradient of Na+ across the cell membrane |
| E. | is not associated with any net movement of Na+ of K+ across the cell membrane |
| Answer» E. is not associated with any net movement of Na+ of K+ across the cell membrane | |
discuss
| 35. | The functions of tropomyosin in skeletal muscle include: |
| A. | releasing Ca2+ after an action potential |
| B. | sliding on actin to produce shortening |
| C. | binding to myosin during contraction |
| D. | acting as a “relaxing protein” at rest by covering up the sites where myosin binds to actin |
| E. | generating ATP which passes to the contractile mechanism |
| Answer» D. acting as a “relaxing protein” at rest by covering up the sites where myosin binds to actin | |
discuss
| 36. | Regarding the autonomic nervous system: |
| A. | it does not have a reflex arch like the somatic nervous system |
| B. | it has dopamine as the main transmitter |
| C. | it has cholinergic division which increases activity of the intestinal musculature and increases gastric excretion |
| D. | neurotransmitter noradrenaline is metabolised by pseudocholinesterase |
| E. | it is not onvolved with visceral sensation (?involved) |
| Answer» C. it has cholinergic division which increases activity of the intestinal musculature and increases gastric excretion | |
discuss
| 37. | Which of the following does NOT act via an intracellular receptor? |
| A. | atrial natriuretic peptide |
| B. | cortisol |
| C. | thyroxine |
| D. | aldosterone |
| E. | retinoic acid |
| Answer» E. retinoic acid | |
discuss
| 38. | Steps involved in skeletal muscle contraction include all of the following EXCEPT: |
| A. | binding of acetylcholine to nicotinic receptors |
| B. | increased Na+ and K+ conductance in end plate membrane |
| C. | spread of depolarisation along T tubules |
| D. | binding of calcium to troponin T, with uncovering of its actin-myosin binding site |
| E. | CTP (cytidine triphosphate) |
| Answer» E. CTP (cytidine triphosphate) | |
discuss
| 39. | Regarding the resting membrane potential in peripheral nerves: |
| A. | membrane permeability of potassium ions via K+ leak channels produces the resting potential |
| B. | a decrease in extracellular Ca2+ decreases excitability |
| C. | decreasing external Na+ concentration lowers the resting membrane potential |
| D. | changing the external Na+ concentration has no effect on the action potential |
| E. | decreasing the external K+ concentration increases the resting membrane potential |
| Answer» A. membrane permeability of potassium ions via K+ leak channels produces the resting potential | |
discuss
| 40. | Regarding excitation-contraction coupling in skeletal muscle, which statement isINCORRECT? |
| A. | calcium ions bind to troponin T |
| B. | troponin I – tropomyosin complex constitutes a “relaxing protein” |
| C. | each cycle of attachment and detachment shortens muscle length by about 1% |
| D. | ATP is the immediate source of energy |
| E. | globular head of myosin – II possesses actin binding site |
| Answer» A. calcium ions bind to troponin T | |
discuss
| 41. | Microglia: |
| A. | are involved with myelin production |
| B. | are scavenger cells |
| C. | are performed in the brain |
| D. | are important in GABA uptake |
| E. | induce capillaries to form tight junctions and thus the blood brain barrier |
| Answer» B. are scavenger cells | |
discuss
| 42. | The action potential: |
| A. | is always monophasic |
| B. | has an absolute refractory period lasting to the start of the after depolarisation |
| C. | has a relative refractory period lasting until repolarisation is complete |
| D. | requires opening of voltage gated Na+ channels |
| E. | results in ↓ K+ conductance |
| Answer» D. requires opening of voltage gated Na+ channels | |
discuss
| 43. | Which of the following nerve fibre types is MOST sensitive to hypoxia? |
| A. | A-alpha |
| B. | A-beta |
| C. | A-delta |
| D. | B |
| E. | C |
| Answer» D. B | |
discuss
| 44. | Regarding smooth muscle contractility, which statement is INCORRECT? |
| A. | increased by acetylcholine |
| B. | decreased by activation of phospholipase C |
| C. | increased by cold |
| D. | decreased by cAMP |
| E. | increased by stretch |
| Answer» B. decreased by activation of phospholipase C | |
discuss
| 45. | Regarding smooth muscle, which statement is INCORRECT? |
| A. | multi-unit smooth muscle is present in the jejunum |
| B. | may exhibit pacemaker potentials |
| C. | mechanical response is much slower than striated muscle |
| D. | the membrane potential is unstable |
| E. | functions as a syncytium in viscera |
| Answer» A. multi-unit smooth muscle is present in the jejunum | |
discuss
| 46. | A sarcomere: |
| A. | contains two separate halves of an A-band and an I-band |
| B. | is the space between two A-bands |
| C. | is between two Z-lines |
| D. | has the T-system of the sarcotubular system at sarcomere junctions |
| E. | contracts when the troponin molecule binds to the myosin head |
| Answer» C. is between two Z-lines | |
discuss
| 47. | Type I muscle fibres: |
| A. | have fast glycolytic rates |
| B. | have low oxidative capacity |
| C. | are more commonly found in muscle that performs explosive work |
| D. | do not have a very high glycolytic capacity |
| E. | are not abundant in endurance athletes |
| Answer» D. do not have a very high glycolytic capacity | |
discuss
| 48. | Regarding cardiac muscle, which statement is INCORRECT? |
| A. | resting membrane potential is about -90mV |
| B. | energy source at rest is mainly fat |
| C. | mechanical response lasts about twice as long as electrical response |
| D. | tetanus cannot occur |
| E. | it has an all-or-nothing contractile response |
| Answer» C. mechanical response lasts about twice as long as electrical response | |
discuss
| 49. | Regarding denervation: |
| A. | it causes skeletal muscle hypertrophy |
| B. | does not lead to fibrillation |
| C. | causes hyposensitivity to acetylcholine in skeletal muscle |
| D. | smooth muscle is able to contract if it occurs in vivo |
| E. | causes fasciculations |
| Answer» D. smooth muscle is able to contract if it occurs in vivo | |
discuss
| 50. | Which of the following nerve fibre types is MOST sensitive to pressure? |
| A. | A-beta |
| B. | A-gamma |
| C. | A-delta |
| D. | B |
| E. | C |
| Answer» A. A-beta | |
discuss
| 51. | Regarding decerebration: |
| A. | decerebration produces spinal shock |
| B. | decerebrate rigidity is spasticity due to diffuse facilitation of stretch reflex |
| C. | there is increased rate of discharge in the α afferent neurons |
| D. | spasticity produced by decerebration is more marked in flexor muscles |
| E. | most commonly produces upper limb flexion and lower limb extension |
| Answer» B. decerebrate rigidity is spasticity due to diffuse facilitation of stretch reflex | |
discuss
| 52. | Which of the following nerve fibre types has the LARGEST diameter? |
| A. | C |
| B. | A-alpha |
| C. | B |
| D. | A-gamma |
| E. | A-beta |
| Answer» B. A-alpha | |
discuss
| 53. | The following are NOT energy sources of muscle: |
| A. | phosphorylcreatine |
| B. | fatty acids |
| C. | glucose |
| D. | glycogen |
| E. | creatine |
| Answer» E. creatine | |
discuss
| 54. | Regarding sensory organ stimulation, which statement is INCORRECT? |
| A. | adaptation occurs over the temperature range 20-40°C |
| B. | pain is sensed by naked nerve endings |
| C. | pacinian corpuscles are rapidly adapting touch-pressure receptors |
| D. | naked nerve endings can detect all four cutaneous sensory modalities |
| E. | any given nerve ending can signal more than one sensory modality |
| Answer» E. any given nerve ending can signal more than one sensory modality | |
discuss
| 55. | Regarding neurotransmitters, which of the following is INCORRECT? |
| A. | glutamate is excitatory |
| B. | GABA is inhibitory at presynaptic neurons |
| C. | glycine is excitatory at postsynaptic neurons |
| D. | GHB (gamma hydroxybutyrate) is inhibitory |
| E. | aspartate is excitatory |
| Answer» C. glycine is excitatory at postsynaptic neurons | |
discuss
| 56. | The stretch reflex: |
| A. | is classically initiated by tapping on the quadriceps muscle |
| B. | is initiated by stretch of the muscle |
| C. | involves impulses being conducted from the muscle spindle to the motor cortex |
| D. | involves extrafusal fibres stimulating annulospiral and flowerspray sensory fibres |
| E. | involves gamma afferents of leksell |
| Answer» B. is initiated by stretch of the muscle | |
discuss
| 57. | Which of the following is NOT present in smooth muscle cells? |
| A. | actin |
| B. | myosin-II |
| C. | tropomyosin |
| D. | almodulin |
| E. | troponin |
| Answer» E. troponin | |
discuss
| 58. | Regarding the structure of cardiac muscle, which statement is INCORRECT? |
| A. | T-system lies at Z-lines |
| B. | functions as a syncytium due to the presence of tight junctions |
| C. | intercalated discs occur at Z-lines |
| D. | contains large numbers of elongated mitochondria |
| E. | thin filaments include troponin T, C and I |
| Answer» B. functions as a syncytium due to the presence of tight junctions | |
discuss
| 59. | Regarding the cardiac muscle action potential, which statement is INCORRECT? |
| A. | sodium ions enter via “fast” channels in phase 0 |
| B. | chloride ions may enter cell during phase 1 |
| C. | sodium ions enter via “slow” channels in phase 2 |
| D. | relative refractory period ends in phase 3 |
| E. | class I anti-arrhythmics reduce the slope of phase 4 |
| Answer» A. sodium ions enter via “fast” channels in phase 0 | |
discuss
| 60. | Which of the following nerve fibre types represents the efferent limb of the musclespindle reflex arc? |
| A. | A-alpha |
| B. | A-beta |
| C. | A-gamma |
| D. | A-delta |
| E. | B |
| Answer» C. A-gamma | |
discuss
| 61. | Regarding neuromuscular transmission, which statement is INCORRECT? |
| A. | smooth muscle cells possess synapses en passant |
| B. | about 10 times as much acetylcholine as is required is released at skeletal muscle neuromuscular junctions |
| C. | antibodies can develop to calcium channels in nerve endings at neuromuscular junctions |
| D. | more than one nerve fibre ends on each end-plate in skeletal muscle |
| E. | acetylcholine is released by exocytosis |
| Answer» D. more than one nerve fibre ends on each end-plate in skeletal muscle | |
discuss
| 62. | Regarding the structure of skeletal muscle, which statement is INCORRECT? |
| A. | thick filaments consist of myosin |
| B. | actin forms a double helix |
| C. | thin filaments include tropomyosin |
| D. | troponin-I inhibits interaction between actin and myosin |
| E. | T-system lies at Z-lines |
| Answer» E. T-system lies at Z-lines | |
discuss
| 63. | Which of the following nerve fibre types has the fastest conduction velocity? |
| A. | B |
| B. | A-delta |
| C. | A-beta |
| D. | A-gamma |
| E. | C |
| Answer» C. A-beta | |
discuss
| 64. | Regarding the nerve fibre action potential, which statement is INCORRECT? |
| A. | does not involve calcium ions |
| B. | after-depolarisation commences when repolarisation is 70% complete |
| C. | total number of ions involved is minute compared to the total number present |
| D. | spike potential peaks at sodium equilibrium potential |
| E. | firing level (threshold) is at about -55mV |
| Answer» D. spike potential peaks at sodium equilibrium potential | |
discuss
| 65. | Which of the following nerve fibre types is MOST sensitive to local anaestheticblockade? |
| A. | A-alpha |
| B. | A-gamma |
| C. | A-delta |
| D. | B |
| E. | C |
| Answer» E. C | |
discuss
| 66. | Regarding neurotoxins, which statement is INCORRECT? |
| A. | tetrodotoxin is a sodium channel blocker |
| B. | tetraethylammonium is a potassium channel blocker |
| C. | tetanospasmin interferes with GABA release |
| D. | botulinum toxin blocks release of acetylcholine |
| E. | latrotoxin causes explosive release of acetylcholine |
| Answer» C. tetanospasmin interferes with GABA release | |
discuss
| 67. | Regarding conduction of nerve impulses, which statement is INCORRECT? |
| A. | it is an active, self-propagating process |
| B. | salutatory conduction occurs in unmyelinated neurons |
| C. | axons can conduct impulses in either direction |
| D. | conduction velocity is proportional to nerve fibre diameter |
| E. | “current sink” occurs in neuronal cell membrane ahead of impulse |
| Answer» B. salutatory conduction occurs in unmyelinated neurons | |
discuss
| 68. | B nerve fibres transmit impulses of which modality? |
| A. | proprioception |
| B. | preganglionic autonomic |
| C. | temperature |
| D. | postganglionic sympathetic |
| E. | somatic motor |
| Answer» B. preganglionic autonomic | |
discuss
| 69. | Regarding nerve fibres, which statement is INCORRECT? |
| A. | resting membrane potential is about -90mV |
| B. | action potentials are generated at the initial segment in spinal motor neurons |
| C. | myelin produces up to 50 times faster conduction of impulses |
| D. | membrane is more permeable to potassium than sodium at rest |
| E. | sodium channels are highly concentrated at the nodes of ranvier |
| Answer» A. resting membrane potential is about -90mV | |
discuss
| 70. | Regarding skeletal muscle, which statement is INCORRECT? |
| A. | resting membrane potential is about -90mV |
| B. | resting length is the length at which active tension in the muscle is maximal |
| C. | total glycogen stored is about 0.4kg |
| D. | energy source at rest is mainly glucose |
| E. | resting heat production is due to basal metabolic processes |
| Answer» D. energy source at rest is mainly glucose | |
discuss
| 71. | Which of the following nerve fibre types has the LEAST myelin? |
| A. | A-alpha |
| B. | A-beta |
| C. | A-gamma |
| D. | B |
| E. | C |
| Answer» E. C | |
discuss
| 72. | A-alpha nerve fibres transmit impulses of which modality? |
| A. | proprioception |
| B. | pain |
| C. | pressure |
| D. | touch |
| E. | motor to muscle spindles |
| Answer» A. proprioception | |
discuss
| 73. | Unmyelinated neurons: |
| A. | do not have Schwann cells associated with them |
| B. | display salutatory conduction |
| C. | constitute most of the cell population in the human central nervous system |
| D. | do not occur in humans |
| E. | none of the above are true |
| Answer» E. none of the above are true | |
discuss
| 74. | In skeletal muscle: |
| A. | thick filaments which are made up of myosin and tropomyosin are lined up to form A bands |
| B. | the dark A band has a light H band in its centre which in turn has an M line in its middle |
| C. | think filaments are made up of actin, tropomyosin and troponin and form the H band |
| D. | Z lines are connected to the thick filaments |
| E. | during contraction, the width of the A band reduces |
| Answer» C. think filaments are made up of actin, tropomyosin and troponin and form the H band | |
discuss
| 75. | Dorsal root (type C) fibres: |
| A. | conduct proprioception |
| B. | are amongst the largest of the nerve fibres |
| C. | are the fibres most susceptible to hypoxia |
| D. | administration of lignocaine suppresses transmission in C fibres before affecting A fibres |
| E. | are myelinated |
| Answer» D. administration of lignocaine suppresses transmission in C fibres before affecting A fibres | |
discuss
| 76. | Saltatory conduction: |
| A. | only occurs in myelinated neurons |
| B. | is slower than non-saltatory conduction |
| C. | is unaffected by local anaesthetics |
| D. | does not occur with anti-dromic conduction |
| E. | is directly proportional in rate to the size of the action potential |
| Answer» A. only occurs in myelinated neurons | |
discuss
| 77. | A motor unit is made up of: |
| A. | a flexor muscle and an extensor muscle |
| B. | a single skeletal muscle and all the motor neurons that supply it |
| C. | a single motor neuron and all the muscle fibres it innervates |
| D. | a large bundle of muscle fibres |
| E. | all the motor neurons in which responses are observed after maximal stimulation |
| Answer» C. a single motor neuron and all the muscle fibres it innervates | |
discuss
| 78. | The role of calcium in excitation/contraction couple in skeletal muscle is: |
| A. | by binding troponin C it uncovers the binding site of actin to interact with the myosin head |
| B. | by binding troponin I, it uncovers the binding site of actin to interact with the myosin head |
| C. | by binding to tropomyosin, it allows troponic to bind to myosin |
| D. | by binding to troponin C, it allows the myosin head to disengage resulting in relaxation |
| E. | it causes depolarisation to spread along the tubules |
| Answer» A. by binding troponin C it uncovers the binding site of actin to interact with the myosin head | |
discuss
| 79. | A decrease in extracellular K+: |
| A. | makes the resting membrane more negative in nerve cells |
| B. | causes a similar effect in nerve cells as a decrease in extracellular Na+ |
| C. | has little effect in nerve cell membrane potential |
| D. | may decrease nerve cell action potential size |
| E. | cause a similar effect in nerve cells as an increase in extracellular Ca++ |
| Answer» E. cause a similar effect in nerve cells as an increase in extracellular Ca++ | |
discuss
| 80. | Tetanic contraction of skeletal muscle: |
| A. | occurs because of the short refractory period of skeletal muscle |
| B. | is due to increased calcium available for binding to troponin C |
| C. | enables a tension development of approximately four times that of individual twitch contraction |
| D. | occurs only with isometric contractions |
| E. | has the same mechanism of that of cardiac muscle |
| Answer» C. enables a tension development of approximately four times that of individual twitch contraction | |
discuss
| 81. | With respect to nerve fibre types: |
| A. | the speed on conduction is inversely proportional to the diameter of the fibre |
| B. | C fibres are more susceptible to local anaesthetics than A fibres |
| C. | Aδ fibres are concerned primarily with somatic motor function |
| D. | pain may be relayed by all fibre types |
| E. | Aδ fibres are efferent only |
| Answer» B. C fibres are more susceptible to local anaesthetics than A fibres | |
discuss
| 82. | In visceral smooth muscle: |
| A. | Ca2+ for contraction is released from sarcoplasmic reticulum |
| B. | membrane potential has a resting value of -90mV |
| C. | the excitation contraction coupling time is rapid (<10ms) |
| D. | muscle contracts when stretched in absence of innervation |
| E. | binding of acetylcholine to nicotine receptors increases Ca2+ influx |
| Answer» D. muscle contracts when stretched in absence of innervation | |
discuss
| 83. | Inhibitory post synaptic potentials involve: |
| A. | localised increase in membrane permeability to Na+ |
| B. | localised decrease in membrane permeability to Cl- |
| C. | localised increase in membrane permeability to PO4 |
| D. | localised increase in membrane permeability to Cl- |
| E. | localised decrease in membrane permeability to K+ |
| Answer» D. localised increase in membrane permeability to Cl- | |
discuss
| 84. | In skeletal muscle relaxation: |
| A. | there is a spread of depolarisation along T tubules |
| B. | Ca2+ is released from troponin |
| C. | there is increase Na+ and K+ conduction in the end plate membranes |
| D. | a resting membrane potential of -65mV is finally reached |
| E. | Mg2+ has a crucial role |
| Answer» B. Ca2+ is released from troponin | |
discuss
| 85. | Regarding synapses: |
| A. | the synaptic cleft is 30-50mm wide |
| B. | transmitters are released from synaptic knobs secondary to Na+ triggers |
| C. | the amount of transmitter released is proportionate to Ca2+ efflux |
| D. | acetylcholine is present in granulated vesicles in synaptic knob |
| E. | the EPSP is caused by Na+ influx |
| Answer» E. the EPSP is caused by Na+ influx | |
discuss
| 86. | Which of the following is inhibitory neurotransmitter? |
| A. | gallamine |
| B. | acetylcholine |
| C. | glutamate |
| D. | glycine |
| E. | aspartate |
| Answer» D. glycine | |
discuss
| 87. | Which of the following nerves is NOT of fibre type A? |
| A. | proprioception |
| B. | touch |
| C. | motor to muscle spindles |
| D. | somatic motor |
| E. | dorsal root pain and temperature |
| Answer» E. dorsal root pain and temperature | |
discuss
| 88. | Which nerve fibre is MOST susceptible to local anaesthetics? |
| A. | proprioception |
| B. | touch |
| C. | motor to muscle spindles |
| D. | somatic motor |
| E. | dorsal root pain and temperature |
| Answer» E. dorsal root pain and temperature | |
discuss
| 89. | Which nerves have the biggest diameter and faster conduction velocity? |
| A. | group A alpha |
| B. | group A beta |
| C. | group A gamma |
| D. | group A delta |
| E. | group C |
| Answer» A. group A alpha | |
discuss
| 90. | In excitation-contraction of skeletal muscle, calcium binds to: |
| A. | tropomyosin |
| B. | myosin |
| C. | troponin I |
| D. | troponin C |
| E. | troponin T |
| Answer» D. troponin C | |
discuss
| 91. | Myosin binding sites on actin are normally covered by: |
| A. | troponin I |
| B. | troponin C |
| C. | troponin T |
| D. | tropomyosin |
| E. | ryanodine molecule |
| Answer» D. tropomyosin | |
discuss
| 92. | With regard to skeletal muscle, which is INCORRECT? |
| A. | the terminal cisterns of sarcoplasmic reticulum lie in contact with T tubules |
| B. | the T tubules surround the muscle at its Z lines |
| C. | the Z line lies within the I band |
| D. | the M line is due to a central bulge in each of the thick filaments |
| E. | the area between two adjacent Z lines is called a sarcomere |
| Answer» B. the T tubules surround the muscle at its Z lines | |
discuss
| 93. | Noradrenaline: |
| A. | is the main neurotransmitter of the parasympathetic nervous system |
| B. | acts as sympathetic neuromuscular junctions in skeletal muscle and vascular smooth muscle |
| C. | is secreted by the adrenal medulla |
| D. | causes pupillary constriction |
| E. | reduces blood pressure |
| Answer» C. is secreted by the adrenal medulla | |
discuss
| 94. | Acetylcholine: |
| A. | is a major neurotransmitter in the spinal cord |
| B. | is degraded within the neuromuscular end-plate by dehydration |
| C. | is important in the stimulation of pancreatic function |
| D. | is the neurotransmitter involved in vagal stimulation of the heart |
| E. | is antagonised by neostigmine |
| Answer» C. is important in the stimulation of pancreatic function | |
discuss
| 95. | The functions of tropomyosin in skeletal muscle include: |
| A. | releasing Ca2+ after an action potential |
| B. | sliding on actin to produce shortening |
| C. | binding to myosin during contraction |
| D. | acting as a “releasing protein” at rest by covering up the sites where myosin binds to actin |
| E. | generating ATP which passes to the contractile mechanism |
| Answer» D. acting as a “releasing protein” at rest by covering up the sites where myosin binds to actin | |
discuss
| 96. | Membrane potential: |
| A. | is only found in nervous tissue |
| B. | is not contributed to by the Na+ /K+ pump |
| C. | magnitude does not change from tissue to tissue |
| D. | is negative inside in relation to the outside |
| E. | is mainly caused by leaking Na+ / K+ channels |
| Answer» D. is negative inside in relation to the outside | |
discuss
| 97. | Gamma amino butyric acid: |
| A. | is an excitatory mediator in the brain |
| B. | is formed by decarboxylation of glutamate |
| C. | acts at three different classes of GABA receptors |
| D. | is mostly secreted unchanged in the urine |
| E. | is the main mediator in glutamate |
| Answer» B. is formed by decarboxylation of glutamate | |
discuss
| 98. | Substance P: |
| A. | is a carbohydrate |
| B. | is a polypeptide found in the intestine and nervous tissue |
| C. | is a β II amino acid residue mainly found in the liver |
| D. | is not involved in the neuroendocrine system |
| E. | is a lipid |
| Answer» B. is a polypeptide found in the intestine and nervous tissue | |
discuss
| 99. | Opioid peptides: |
| A. | are not formed from precursors |
| B. | include morphine as an example |
| C. | form the opioid receptors in the brain |
| D. | are mainly found in the brain and gastrointestinal tract |
| E. | are almost always excreted unchanged |
| Answer» D. are mainly found in the brain and gastrointestinal tract | |
discuss
| 100. | Regarding the autonomic nervous system: |
| A. | does not have a reflex arc like somatic nervous system |
| B. | has dopamine as the main transmitter |
| C. | has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion |
| D. | neurotransmitter noradrenaline is metabolised by pseudocholinesterase |
| E. | is not involved with visceral sensation |
| Answer» C. has cholinergic division which increases activity of the intestinal musculature and increases gastric secretion | |
discuss
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