

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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