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Chapter:

100+ Nervous System Solved MCQs

in Physiology

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Biology .

Chapters

Chapter: Nervous System
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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