McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Biology .
Chapters
| 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 | |
| 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 | |
| 53. |
The following are NOT energy sources of muscle: |
| A. | phosphorylcreatine |
| B. | fatty acids |
| C. | glucose |
| D. | glycogen |
| E. | creatine |
| Answer» E. creatine | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 60. |
Which of the following nerve fibre types represents the efferent limb of the muscle spindle reflex arc? |
| A. | A-alpha |
| B. | A-beta |
| C. | A-gamma |
| D. | A-delta |
| E. | B |
| Answer» C. A-gamma | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 65. |
Which of the following nerve fibre types is MOST sensitive to local anaesthetic blockade? |
| A. | A-alpha |
| B. | A-gamma |
| C. | A-delta |
| D. | B |
| E. | C |
| Answer» E. C | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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++ | |
| 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 | |
| 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 | |
| 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 | |
| 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- | |
| 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 | |
| 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 | |
| 86. |
Which of the following is inhibitory neurotransmitter? |
| A. | gallamine |
| B. | acetylcholine |
| C. | glutamate |
| D. | glycine |
| E. | aspartate |
| Answer» D. glycine | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
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