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FRCA Physiology > Neuronal physiology > Flashcards

Neuronal physiology Flashcards

1
Q

The Sodium/Potassium ATPase pump:

Is confined to nerve and muscle cells

A

False. It is found in many parts of the body.

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2
Q

The Sodium/Potassium ATPase pump:

Is associated with the removal of 2 sodium and entry of 3 potassium ions into the cell

A

False. The ratio is 3 sodium to 2 potassium.

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3
Q

The Sodium/Potassium ATPase pump:

Requires magnesium for pump activity

A

False. It does not require other ions.

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4
Q

The Sodium/Potassium ATPase pump:

Is the cause of high intracellular potassium compared with sodium

A

True. This maintains the cell homeostasis.

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5
Q

The Sodium/Potassium ATPase pump:

Keeps the osmotic balance within the cell

A

True. Pump failure will lead to sodium entering the cell, followed by water.

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6
Q

The resting membrane potential of a nerve fibre:

Depends upon the electropositive charge in the interior of the nerve

A

False. The interior of the cell is electronegative.

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7
Q

The resting membrane potential of a nerve fibre:

Increases when extracellular potassium concentration decreases

A

False. The resting potential will become more negative as extracellular potassium concentrations drop. The Nernst potential will become more negative with respect to the inside of the nerve.

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8
Q

The resting membrane potential of a nerve fibre:

Is obliterated when local anaesthetic is applied

A

False. Local anaesthetic impairs the passage of ions across the membrane. They don’t alter the RMP itself.

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9
Q

The resting membrane potential of a nerve fibre:

Is dependent on a threshold stimulus of sufficient magnitude

A

False. The RMP is independent of the threshold stimulus.

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10
Q

The resting membrane potential of a nerve fibre:

Is abolished by acetylcholine (Ach)‏

A

False. ACh doesn’t abolish the resting membrane potential.

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11
Q

The action potential:

Is generated by differing ionic concentrations of sodium and potassium

A

True

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12
Q

The action potential:

A negative potential inside the nerve drives potassium ions outside the cell

A

False. The potential itself does not drive potassium ion flux. They move out of the cell due to the concentration gradient set up by the Na/K pump.

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13
Q

The action potential:

Depolarization is caused by the transfer of sodium ions across the membrane

A

True

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14
Q

The action potential:

In the resting state the potential inside the nerve fibre is +85 mV

A

False. The resting potential in a nerve cell is about -70 mV.

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15
Q

The action potential:

At the peak of the action potential the voltage change is 35 mV

A

False. The electrical potential rises by about 105 mV to +35 mV.

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16
Q

Regarding the neuromuscular junction:

An action potential leads to the release of about 125 ACh vesicles

A

True. An action potential leads to the release of about 125 ACh vesicles.

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17
Q

Regarding the neuromuscular junction:

Opening of the ACh channels in the muscle membrane first allows an efflux of K+ ions

A

False. The initial action is influx of sodium.

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18
Q

Regarding the neuromuscular junction:

Acetylcholine binds to the beta subunit of the receptor

A

False. Two ACh molecules bind to the alpha subunits.

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19
Q

Regarding the neuromuscular junction:

Acetylcholinesterase in the synaptic cleft is bound to connective tissue

A

True. Acetylcholinesterase is bound to the basal lamina of connective tissue within the cleft.

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20
Q

Regarding the neuromuscular junction:

A sensation of fatigue is usually due to depletion of acetylcholine stores

A

False. Although NMJ fatigue (and depletion of ACh) can occur, it is rare and only at the extremes of activity.

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21
Q

Fibre types used for nervous system transmission include:

Sensory fibres from muscle tendon Golgi organs of type Aα

A

True

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22
Q

Fibre types used for nervous system transmission include:

Type Aγ fibres with a diameter of 0.25 microns

A

False. Type A fibres are divided into subtypes. Aγ fibres are 3-6 microns in diameter.

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23
Q

Fibre types used for nervous system transmission include:

Unmyelinated C fibres conducting at 1 ms-1

A

True

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24
Q

Fibre types used for nervous system transmission include:

Type Aγ fibres transmitting sympathetic motor impulses

A

False. Aγ fibres innervate muscle spindles. The sympathetic nervous system contains B and C fibres.

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25
Q

Fibre types used for nervous system transmission include:

Fibres of type Aβ transmitting from vibration sensing organs

A

True. They also transmit proprioception impulses.

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26
Q

Aα fibres have a conduction velocity of 70-120 ms-1

A

True

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27
Q

B fibres are all unmyelinated

A

False. B fibres are sympathetic and are mostly myelinated.

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28
Q

Aβ fibres convey afferent touch stimuli

A

True

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29
Q

Unmyelinated fibres can transmit at only 20 ms-1

A

False. Unmyelinated fibres transmit at lower velocities (in the range of 0.5-2 ms-1).

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30
Q

Conduction velocity is dependent upon nerve fibre diameter

A

True. Fibre diameters decrease through the group (from A to D)‏.

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31
Q

With regards to Axons:

Are classified according to conduction velocity

A

True

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32
Q

With regards to Axons:

Connecting sympathetic ganglia to the cord are unmyelinated

A

False. Preganglionic sympathetic fibres are white rami and are myelinated (it is the myelin that makes them white)‏.

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33
Q

With regards to Axons:

Arising from the alpha motor neurones have large diameters in comparison to other nerves

A

True. Compared to other nerve fibres, see table.

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34
Q

With regards to Axons:

Can conduct impulses in either direction

A

True. Axons can conduct in either direction, however synapses won’t work both ways.

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35
Q

With regards to Axons:

Are absolutely refractory during the period of increased potassium conductance

A

False. Absolute refractory period is related to sodium channel inactivation.

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36
Q

The conduction velocity of an action potential:

Is inversely related to the cross-sectional area of the axon

A

False. Larger axons conduct more quickly.

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37
Q

The conduction velocity of an action potential:

Is faster in a myelinated fibre than in an unmyelinated one

A

True. Myelinated fibres conduct up to 50 times faster, due to ‘saltatory’ conduction- jumping between nodes of Ranvier.

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38
Q

The conduction velocity of an action potential:

Is increased by cooling the nerve

A

False. Like most biological systems, it slows with cooling.

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39
Q

The conduction velocity of an action potential:

Can exceed 100 ms-1 in humans

A

True. Maximum velocity is up to 120 ms-1 in some A fibres.

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40
Q

The conduction velocity of an action potential:

Is highest in pre-ganglionic autonomic fibres

A

False. Pre-ganglionic fibres are in group B, conducting at 3-14 ms-1.

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41
Q

These modalities correspond to their pathways:

Proprioception via the dorsal columns

A

True. The dorsal columns transmit fine touch and proprioception.

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42
Q

These modalities correspond to their pathways:

Temperature and pain via the contralateral spinothalamic tracts

A

True

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43
Q

These modalities correspond to their pathways:

Fibres carrying fine touch sensation form the gracile and cuneate nuclei

A

True. Fine touch is transmitted in the posterior white column in the medial and lateral fasciculi, connecting to their respective cuneate and gracile nuclei.

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44
Q

These modalities correspond to their pathways:

Proprioception and the pyramidal tract

A

False. The pyramidal tract is a descending (motor) tract. The posterior and anterior spinocerebellar tracts ascend in the lateral column and transmit proprioception to the cerebellum without crossing.

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45
Q

These modalities correspond to their pathways:

Spinocerebellar tracts cross before reaching the cerebellum

A

False

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46
Q

Immediately after complete transection of the spinal cord the following features may be found below the lesion:
Loss of motor power but preservation of limb reflexes

A

False. Spinal shock ensues immediately after cord transection. This includes loss of reflexes. Hyper-reflexia occurs 2-6 weeks later.

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47
Q

Immediately after complete transection of the spinal cord the following features may be found below the lesion:
Urinary incontinence

A

True

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48
Q

Immediately after complete transection of the spinal cord the following features may be found below the lesion:
Loss of muscle power but preservation of sensation

A

False. Sensation will also be lost.

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49
Q

Immediately after complete transection of the spinal cord the following features may be found below the lesion:
Flaccid paralysis with loss of limb reflexes

A

True

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50
Q

Immediately after complete transection of the spinal cord the following features may be found below the lesion:
Loss of muscle power but preservation of muscle joint position sense

A

False. Joint position sense is also lost.

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51
Q

Concerning pain pathways:

The cell bodies of Aδ and C fibres reside within the dorsal root ganglion of the spinal cord

A

True. They are both first order neurones.

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52
Q

Concerning pain pathways:

Aδ fibres synapse with cells of the substantia gelatinosa of the spinal cord

A

False. Aδ fibres synapse with cells in laminae I and V of the dorsal horn whereas C fibres synapse with cells in the substantia gelatinosa (laminae II and III).

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53
Q

Concerning pain pathways:

C fibres synapse with cells in laminae II and III in the dorsal horn

A

True

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54
Q

Concerning pain pathways:

Most ascending neurones are in the anterolateral columns

A

True. Most second order neurones cross within a few segments and ascend in the anterolateral columns (spinothalamic tract).

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55
Q

Concerning pain pathways:

The substantia gelatinosa projects directly to higher levels

A

False

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56
Q

Spinal cord hemisection (The Brown-Sequard Syndrome) causes:

Contralateral paralysis

A

False. The Brown-Sequard Syndrome causes ipsilateral paralysis.

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57
Q

Spinal cord hemisection (The Brown-Sequard Syndrome) causes:

Ipsilateral loss of proprioception

A

True

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58
Q

Spinal cord hemisection (The Brown-Sequard Syndrome) causes:

Ipsilateral loss of pain sensation

A

False. Pain and temperature sensation are lost contra-laterally.

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59
Q

Spinal cord hemisection (The Brown-Sequard Syndrome) causes:

Contralateral loss of vibration sense

A

False. Vibration sense is carried by the ipsilateral dorsal columns.

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60
Q

Spinal cord hemisection (The Brown-Sequard Syndrome) causes:

Contralateral loss of temperature sensation

A

False

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61
Q

A reflex action:

May be carried out by glands, skeletal, smooth or cardiac muscle

A

True. The effector organs are usually muscles or glands which contract or secrete chemicals producing suitable responses.

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62
Q

A reflex action:

Is influenced by higher centres in the brain

A

True. The reflex pathways can be influenced by higher centres via the upper motor neurone descending tracts e.g. the cortico/rubro/reticulo/vestibulo/tecto-spinal tracts.

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63
Q

A reflex action:

Results from activity in at least two central nervous synapses in series

A

False. Monosynaptic reflexes (e.g. the stretch reflex) involve only one synapse.

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64
Q

A reflex action:

May involve simultaneous relaxation of some skeletal muscles and contraction of others

A

True. During a stretch reflex, the muscles that antagonise the action of the muscles involved relax due to reciprocal innervation.

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65
Q

A reflex action:

Can be either monosynaptic or polysynaptic

A

True

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66
Q

The knee jerk reflex:

Starts with stimulation of receptors in the patellar tendon

A

False. Receptors are spindles in the muscle.

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67
Q

The knee jerk reflex:

Is propagated through the lumbar segment L2

A

True. The knee jerk sensory fibre is a Ia fibre which synapses with an alpha motor neurone at the level of L2.

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68
Q

The knee jerk reflex:

Has a reflex arc which involves a single interneurone

A

False. It is independent of higher centres although can be influenced by activity in higher centres.

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69
Q

The knee jerk reflex:

Involves the femoral nerve

A

True. The femoral nerve supplies quadriceps.

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70
Q

The knee jerk reflex:

Is preserved immediately after transection of the spinal cord at T6

A

False. Transection of the cord is followed by a variable degree of spinal shock where all reflexes are depressed or absent. Recovery of reflexes may take up to 6 weeks.

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71
Q

The vagus nerve:

Has little direct effect on the strength of ventricular contraction

A

True

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72
Q

The vagus nerve:

Contains afferent and efferent fibres

A

True

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73
Q

The vagus nerve:

Contains parasympathetic post-ganglionic fibres

A

False. The preganglionic fibres of the parasympathetic division run almost to the organ innervated and then synapse in ganglia within the organ.

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74
Q

The vagus nerve:

Contains fibres which regulate gastric acid secretion

A

True

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75
Q

The vagus nerve:

Has a role in bladder emptying

A

False. The parasympathetic innervation of the bladder originates from the S2,3,4 segments of the spinal cord and preganglionic fibres passing through the pelvic nerves. Parasympathetic stimulation causes detrusor contraction and trigone + sphincter relaxation.

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76
Q

Concerning the sympathetic nervous system:

Preganglionic fibres are all unmyelinated

A

False

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77
Q

Concerning the sympathetic nervous system:

Synapses are in the lateral horn

A

False. The synapses are most frequently found in the sympathetic chains either side of the cord.

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78
Q

Concerning the sympathetic nervous system:

It transmits sensation of pain

A

True

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79
Q

Concerning the sympathetic nervous system:

Preganglionic fibres are shorter than postganglionic fibres

A

True

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80
Q

Concerning the sympathetic nervous system:

It has adrenergic ganglia

A

False. Post ganglionic synapses use norepinephrine as the neurotransmitter. The only exception is the neurones terminating in sweat glands, which use Acetylcholine.

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81
Q

Vagal efferent stimulation results in:

Decreased insulin secretion

A

False. Insulin secretion is increased.

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82
Q

Vagal efferent stimulation results in:

Decreased physiological dead space

A

True. It also causes bronchoconstriction thus reducing anatomical and therefore physiological dead space.

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83
Q

Vagal efferent stimulation results in:

Decreased gastrin secretion

A

False. Gastrin secretion is increased.

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84
Q

Vagal efferent stimulation results in:

Increased gastric acid secretion

A

True

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85
Q

Vagal efferent stimulation results in:

A reduction in bile production

A

False. Bile secretion is also increased.

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86
Q

The following receive only sympathetic innervation:

Lacrimal glands

A

False. The lacrimal glands are one of the few organs receiving only parasympathetic fibres.

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87
Q

The following receive only sympathetic innervation:

Piloerector Muscles

A

True. One of the few exceptions to dual sympathetic/parasympathetic control.

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88
Q

The following receive only sympathetic innervation:

Adipose tissue

A

True. Sympathetic innervation allows for mobilisation of fat stores.

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89
Q

The following receive only sympathetic innervation:

Juxtaglomerular apparatus

A

True

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90
Q

The following receive only sympathetic innervation:

Pupils

A

False. Pupils are under dual control. Sympathetic system causes mydriasis (pupil dilatation) whereas parasympathetic stimulation results in miosis (pupil constriction).

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91
Q

The membrane potential of a nerve fibre:

Is directly proportional to the diameter of the fibre

A

False

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92
Q

The membrane potential of a nerve fibre:

Is measured conventionally as negative on the inside

A

True

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93
Q

The membrane potential of a nerve fibre:

Represents an imbalance of charge across the two sided of a semi-permeable membrane

A

True

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94
Q

The membrane potential of a nerve fibre:

Reverses its polaity during an action potential

A

True

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95
Q

The membrane potential of a nerve fibre:

Can be calculated from the nernst equation

A

False

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96
Q

Compared with plasma, CSF contains:

Less Sodium

A

True

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97
Q

Compared with plasma, CSF contains:

Lower osmolality

A

False

98
Q

Compared with plasma, CSF contains:

More hydrogen ions

A

True

99
Q

Compared with plasma, CSF contains:

A higher PCo2

A

True

100
Q

Compared with plasma, CSF contains:

More urea

A

False

101
Q

Concerning cerebral blood flow:

Blood flow in the grey matter may be twice that in the white matter

A

True

102
Q

Concerning cerebral blood flow:

Is inversely proportional to PaCO2

A

False

103
Q

Concerning cerebral blood flow:

Is predominantly provided by the external carotid artery

A

False

104
Q

Concerning cerebral blood flow:

Is reduced with acidosis

A

False

105
Q

Concerning cerebral blood flow:

It is equal to 10% of cardiac output

A

False

106
Q

The knee jerk reflex:

Is due to stimulation of receptors in the patellar tendon

A

False

107
Q

The knee jerk reflex:

Has a reflex arc which involves a single interneurone

A

False

108
Q

The knee jerk reflex:

The afferent pathway is via AA delta fibres

A

False

109
Q

The knee jerk reflex:

Hypereflexia of the patella is known as westphal’s sign

A

False

110
Q

The knee jerk reflex:

is abolished immediately after transection of the spinal cord at T6

A

True

111
Q

These modalities correspond to their correct pathways:

Temperature and pain via the ipsilateral spinothalamic tracts

A

False

112
Q

These modalities correspond to their correct pathways:

Fibres subserving fine touch from the gracile and cuneate nuclei

A

True

113
Q

These modalities correspond to their correct pathways:

Proproception via the dorsal columns

A

True

114
Q

These modalities correspond to their correct pathways:

Spinocerebellar tracts relay information from muscles

A

True

115
Q

These modalities correspond to their correct pathways:

Pain and the spinotectal tract

A

True

116
Q

When the nerve cell membrane is depolarised:

Sodium permeability falls slowly, producing an action potential

A

False

117
Q

When the nerve cell membrane is depolarised:

Sodium permeability is raised until the resting membrane potential is restored

A

False

118
Q

When the nerve cell membrane is depolarised:

Increased calcium permeability produces a plateau phase

A

False

119
Q

When the nerve cell membrane is depolarised:

The change in sodium permeability is directly responsible for impulse transmission

A

True

120
Q

When the nerve cell membrane is depolarised:

Sodium efflux is self limiting

A

True

121
Q

The nerve action potential:

Transmission is saltatory between the nodes of ranvier

A

True

122
Q

The nerve action potential:

Is conducted slower in the myelinated fibres

A

False

123
Q

The nerve action potential:

Is propogated exponentially

A

False

124
Q

The nerve action potential:

Is approx 35mV above resting potention

A

False

125
Q

The nerve action potential:

Is initiated by sodium influx

A

True

126
Q

In complete cord transection:

Arterial blood pressure becomes labile

A

True

127
Q

In complete cord transection:

Autonomic hypereflexia occurs within a few days

A

False

128
Q

In complete cord transection:

Tendon reflexes are the first to recover

A

False

129
Q

In complete cord transection:

Recovery of reflexes occurs at around 6 months

A

False

130
Q

In complete cord transection:

There is a total loss in sensation from dermatomes below the level of injury

A

True

131
Q

Cerebral bloodflow:

A high Pa O2 causes cerebral vasoconstriction

A

True

132
Q

Cerebral bloodflow:

The normal jugular venous saturation is about 65%

A

True

133
Q

Cerebral bloodflow:

Can be estimated by doppler

A

True

134
Q

Cerebral bloodflow:

acidosis induces cerebral vasodilation is independent of PaCO2

A

True

135
Q

Cerebral bloodflow:

A decrease in arterial pressure causes vasoconstriction of cerebral vessels

A

False

136
Q

The conduction velocity along a nerve:

Is increased by myelination

A

True

137
Q

The conduction velocity along a nerve:

Increases when the serum potassium is low

A

False

138
Q

The conduction velocity along a nerve:

Increases with diameter

A

True

139
Q

The conduction velocity along a nerve:

Is greater in delta than alpha fibres

A

False

140
Q

The conduction velocity along a nerve:

Is greater in motor than in sensory nerve

A

True

141
Q

The action potential:

Depolarization is caused by the transfer of sodium ions across the membrane

A

True

142
Q

The action potential:

In the resting state the potential inside the nerve fibre is +85mV

A

False

143
Q

The action potential:

Is generated by differing ionic concentrations of sodium and potassium

A

True

144
Q

The action potential:

Occurs when the membrane depolarises by 15mV

A

True

145
Q

The action potential:

Has 4 phases

A

False

146
Q

Stimulation of the parasympathetic nervous system causes:

Bladder relaxation

A

False

147
Q

Stimulation of the parasympathetic nervous system causes:

Gall-bladder contraction

A

True

148
Q

Stimulation of the parasympathetic nervous system causes:

Bronchodilation

A

False

149
Q

Stimulation of the parasympathetic nervous system causes:

Miosis

A

True

150
Q

Stimulation of the parasympathetic nervous system causes:

Decreased insulin secretion

A

False

151
Q

Concerning intracranial pressure:

Tonsillar (cerebellar) herniation causes ipsilateral pupillary dilation

A

False

152
Q

Concerning intracranial pressure:

The effect of hypocapnia-induced cerebral vasoconstriction is maintaines for 12 hours or more

A

False

153
Q

Concerning intracranial pressure:

Normal ICP is 10-20 mmHg

A

False

154
Q

Concerning intracranial pressure:

ICP increases linearly with increasing cerebral blood volume

A

False

155
Q

Concerning intracranial pressure:

Lundberg B pressure waves may be a normal finding

A

False

156
Q

The following are parasympathetic ganglia:

Ciliary ganglion

A

True

157
Q

The following are parasympathetic ganglia:

Otic Ganglian

A

True

158
Q

The following are parasympathetic ganglia:

Stellate ganglion

A

False

159
Q

The following are parasympathetic ganglia:

Gasserian ganglion

A

False

160
Q

The following are parasympathetic ganglia:

Coeliac ganglion

A

False

161
Q

The chemical mediator released at the following sites is acetylcholine:
Parasympathetic preganglionic neurones

A

True

162
Q

The chemical mediator released at the following sites is acetylcholine:
Parasympathetic postganglionic neurones

A

True

163
Q

The chemical mediator released at the following sites is acetylcholine:
Sympathetic postganglionic neurones which innervate the heart

A

False

164
Q

The chemical mediator released at the following sites is acetylcholine:
Sympathetic preganglionic neurones

A

True

165
Q

The chemical mediator released at the following sites is acetylcholine:
Sympathetic postganglionic neurones which innervate sweat glands

A

True

166
Q

The autoregulation of cerebral blood flow:

Curve shows a shift to the left in chronic hypertension

A

False

167
Q

The autoregulation of cerebral blood flow:

Is maintained under hypoxic conditions

A

False

168
Q

The autoregulation of cerebral blood flow:

Remains constant over a range of systolic blood pressures from 60-140 mmHg

A

False

169
Q

The autoregulation of cerebral blood flow:

Is impaired in hypercapnia

A

True

170
Q

The autoregulation of cerebral blood flow:

Is altered in the acute phase following a subarachnoid haemorrhage

A

True

171
Q

The pathways of pain sensation include:

C fibres which release histamine and serotonin

A

False

172
Q

The pathways of pain sensation include:

A-delta fibres which terminate in lamina 1 of the dorsal horn

A

True

173
Q

The pathways of pain sensation include:

A-gamma fibres synapsing in the dorsal horn

A

False

174
Q

The pathways of pain sensation include:

Second order neurones which ascend in the ipsilateral spinothalamic tracts

A

False

175
Q

The pathways of pain sensation include:

Descending pathways in the dorsolateral columns

A

True

176
Q

In the autonomic nervous system:

Parasympathetic nervous system stimulation produces coronary vasodilation

A

True

177
Q

The pathways of pain sensation include:

The stellate ganglia impair myocardial contractility

A

False

178
Q

The pathways of pain sensation include:

Post-ganglionic sympathetic nerves increase catecholamine releases from the adrenal glands

A

False

179
Q

The pathways of pain sensation include:

All preganglionic neurones are cholinergic

A

True

180
Q

The pathways of pain sensation include:

Alpha-2 stimulation modifies intracellular cGMP levels

A

False

181
Q

Acetylcholine:

Is the neurotransmitter at all parasympathetic postganglionic nerve endings

A

True

182
Q

Acetylcholine:

Is generated from choline synthesized with axoplasm

A

False

183
Q

Acetylcholine:

Its synthesis is catalysed by the enzyme choline acetylesterase

A

False

184
Q

Acetylcholine:

Is an ester

A

True

185
Q

Acetylcholine:

Raises the membrane permeability to sodium and calcium in the heart

A

False

186
Q

Regarding the cerebral circulation:

The circle of willis is formed from the internal carotid and vertebral arteries only

A

True

187
Q

Regarding the cerebral circulation:

The middle cerebral artery is most commonly affected by a CVA

A

True

188
Q

Regarding the cerebral circulation:

The anterior spinal artery is a branch of the vertebral artery

A

True

189
Q

Regarding the cerebral circulation:

The posterior spinal artery is a branch of the vertebral artery

A

True

190
Q

Regarding the cerebral circulation:

The anterior cerebral artery supplies the superior and medial parts of the cerebral hemisphere

A

True

191
Q

Concerning the enteric nervous system:

It contains pre-ganglionic cholinergic fibres

A

True. Generally, the parasympathetic supply to the GIT is via pre-ganglionic vagal fibres.

192
Q

Concerning the enteric nervous system:

Vagal fibres are post-ganglionic

A

False.

193
Q

Concerning the enteric nervous system:

It contains post-ganglionic sympathetic fibres

A

True. The sympathetic supply is post-ganglionic, but may end on cholinergic neurones or on smooth muscle fibres directly.

194
Q

Concerning the enteric nervous system:

Many sympathetic fibres end on cholinergic neurones

A

True

195
Q

Concerning the enteric nervous system:

Many sympathetic fibres end directly on intestinal smooth muscle

A

True

196
Q

Concerning nerve conduction:

A-delta fibres are the slowest as they are unmyelinated

A

False. A and B fibres are myelinated and therefore have fast conduction velocities due to saltatory conduction.

197
Q

Concerning nerve conduction:

A-beta fibres exhibit saltatory conduction

A

True.

198
Q

Concerning nerve conduction:

C fibres are myelinated

A

False.

199
Q

Concerning nerve conduction:

A-alpha fibres conduct at 30-70 m/s

A

False. A-alpha fibres conduct at 70-120 m/s

200
Q

Concerning nerve conduction:

A-delta fibres provide sensory innervation to muscle spindles.

A

False. But A-gamma fibres provide motor supply to muscle spindles.

201
Q

Hemisection of the spinal cord causes:

Ipsilateral paralysis

A

True

202
Q

Hemisection of the spinal cord causes:

Ipsilateral loss of proprioception

A

True

203
Q

Hemisection of the spinal cord causes:

Contralateral loss of pain sensation

A

True

204
Q

Hemisection of the spinal cord causes:

Ipsilateral loss of vibration sense

A

True

205
Q

Hemisection of the spinal cord causes:

Contralateral loss of temperature sensation

A

True

206
Q

Concerning synaptic transmission:

The synaptic cleft is 100 nm wide

A

False. The synaptic cleft is 30-50 nm wide.

207
Q

Concerning synaptic transmission:

Temporal summation may occur

A

True. Summation of excitatory postsynaptic potentials may be both spatial and temporal.

208
Q

Concerning synaptic transmission:

Synaptic delay is normally 0.1 ms

A

False. Synaptic delay is normally 0.5 ms.

209
Q

Concerning synaptic transmission:

IPSPs are depolarising

A

False. IPSPs are hyperpolarising.

210
Q

Concerning synaptic transmission:

EPSPs are depolarising

A

True.

211
Q

Concerning the knee jerk reflex:

It is monosynaptic

A

True

212
Q

Concerning the knee jerk reflex:

The synaptic transmitter is glutamate

A

True

213
Q

Concerning the knee jerk reflex:

The sensory organ is the muscle spindle

A

True

214
Q

Concerning the knee jerk reflex:

It involves spinal roots L2,3,4

A

True

215
Q

Concerning the knee jerk reflex:

Glycine inhibition occurs in fibres to antagonistic muscles.

A

True

216
Q

Concerning the visual pathway:

Optic tract lesions will cause a bitemporal hemianopia

A

False. Optic tract lesions cause homonymous hemianopia since the optic tracts carry fibres that supply the same field (ie left or right) from both eyes.

217
Q

Concerning the visual pathway:

Optic chiasm lesions will cause a bitemporal hemianopia

A

True. As at the Optic chiasm, temporal fibres cross the midline.

218
Q

Concerning the visual pathway:

Occipital lesions may spare the macula

A

True. As the macula fibres are separated from the rest of the cortex subserving vision.

219
Q

Concerning the visual pathway:

Optic nerve lesions will cause bilateral loss of vision

A

False. They will cause unilateral loss of vision.

220
Q

Concerning the visual pathway:

Field defects start as scotomas.

A

True. These are small areas of visual loss.

221
Q

Concerning pain pathways:

A-delta have cell bodies within the vental root ganglion of the spinal cord

A

False. A-delta have cell bodies within the dorsal root ganglia.

222
Q

Concerning pain pathways:

A-delta fibres synapse with cells of the substantia gelatinosa of the spinal cord

A

False. A-delta fibres synapse with cells in laminae I and V of the dorsal horn.

223
Q

Concerning pain pathways:

C fibres synapse with cells in laminae IV and V in the dorsal horn

A

False. C fibres synapse with cells in laminae II and III in the dorsal horn.

224
Q

Concerning pain pathways:

Most ascending neurones are in the anterolateral columns

A

True. Most second order neurones cross within a few segments and ascend in the anterolateral columns (spinothalamic tract).

225
Q

Concerning pain pathways:

The substantia gelatinosa projects directly to higher levels

A

False. The SG does not project directly to higher levels but contains multiple interneurones involved in pain modification.

226
Q

Concerning sensory receptors:

Meissners corpuscles are associated with nociception

A

False. Meissners corpuscles are associated with touch.

227
Q

Concerning sensory receptors:

Ruffini corpuscles are associated with proprioception

A

True.

228
Q

Concerning sensory receptors:

Pacinian corpuscles are associated with vibration

A

True. Pacinian corpuscles are associated with proprioception and vibration.

229
Q

Concerning sensory receptors:

Ruffini corpuscles are associated with nociception

A

False. Free nerve endings are associated with nociception

230
Q

Concerning sensory receptors:

Pacinian corpuscles are associated with proprioception

A

True. Pacinian corpuscles are associated with proprioception and vibration.

231
Q

Concerning the cranial nerves:

VII provides taste sensation to the posterior third of the tongue

A

False. Taste sensation to the posterior third of the tongue is provided by the glossopharyngeal (IX), the rest being supplied by the chorda tympani accompanying the facial nerve (VII).

232
Q

Concerning the cranial nerves:

V provides motor fibres to the jaw and tongue

A

False. The trigeminal nerve (V) supplies the muscles of mastication and sensation to the forehead and face in the distribution ophthalmic, maxillary and mandibular branches. This includes sensation from the cornea.

233
Q

Concerning the cranial nerves:

IV innervates the inferior oblique muscle

A

False. IV innervates the superior oblique muscle.

234
Q

Concerning the cranial nerves:

III performs most eye movements

A

True. With IV and VI supplying superior oblque (to look down and inward) and lateral rectus (abduction) respectively.

235
Q

Concerning the cranial nerves:

XII provides motor innervation to palatoglossus

A

False. XII innervates all tongue muscles except palatoglossus, which is innervated by X.

236
Q

In the EEG, delta waves occur:

With increased cortical activity

A

False

237
Q

In the EEG, delta waves occur:

Normally during sleep

A

True

238
Q

In the EEG, delta waves occur:

Prominently over the frontal area

A

False

beta waves prominent over the frontal area.

239
Q

In the EEG, delta waves occur:

Upon closing the eyes

A

False

Alpha waves are prominent on closing the eyes or with increased cortical activity

240
Q

In the EEG, delta waves occur:

Normally in children

A

True

FRCA Physiology (6 decks)

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