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.
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.
3
Q
The Sodium/Potassium ATPase pump:
Requires magnesium for pump activity
A
False. It does not require other ions.
4
Q
The Sodium/Potassium ATPase pump:
Is the cause of high intracellular potassium compared with sodium
A
True. This maintains the cell homeostasis.
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.
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.
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.
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.
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.
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.
11
Q
The action potential:
Is generated by differing ionic concentrations of sodium and potassium
A
True
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.
13
Q
The action potential:
Depolarization is caused by the transfer of sodium ions across the membrane
A
True
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.
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.
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.
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.
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.
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.
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.
21
Q
Fibre types used for nervous system transmission include:
Sensory fibres from muscle tendon Golgi organs of type Aα
A
True
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.
23
Q
Fibre types used for nervous system transmission include:
Unmyelinated C fibres conducting at 1 ms-1
A
True
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.
25
Fibre types used for nervous system transmission include:
| Fibres of type Aβ transmitting from vibration sensing organs
True. They also transmit proprioception impulses.
26
Aα fibres have a conduction velocity of 70-120 ms-1
True
27
B fibres are all unmyelinated
False. B fibres are sympathetic and are mostly myelinated.
28
Aβ fibres convey afferent touch stimuli
True
29
Unmyelinated fibres can transmit at only 20 ms-1
False. Unmyelinated fibres transmit at lower velocities (in the range of 0.5-2 ms-1).
30
Conduction velocity is dependent upon nerve fibre diameter
True. Fibre diameters decrease through the group (from A to D).
31
With regards to Axons:
| Are classified according to conduction velocity
True
32
With regards to Axons:
| Connecting sympathetic ganglia to the cord are unmyelinated
False. Preganglionic sympathetic fibres are white rami and are myelinated (it is the myelin that makes them white).
33
With regards to Axons:
| Arising from the alpha motor neurones have large diameters in comparison to other nerves
True. Compared to other nerve fibres, see table.
34
With regards to Axons:
| Can conduct impulses in either direction
True. Axons can conduct in either direction, however synapses won’t work both ways.
35
With regards to Axons:
| Are absolutely refractory during the period of increased potassium conductance
False. Absolute refractory period is related to sodium channel inactivation.
36
The conduction velocity of an action potential:
| Is inversely related to the cross-sectional area of the axon
False. Larger axons conduct more quickly.
37
The conduction velocity of an action potential:
| Is faster in a myelinated fibre than in an unmyelinated one
True. Myelinated fibres conduct up to 50 times faster, due to ‘saltatory’ conduction- jumping between nodes of Ranvier.
38
The conduction velocity of an action potential:
| Is increased by cooling the nerve
False. Like most biological systems, it slows with cooling.
39
The conduction velocity of an action potential:
| Can exceed 100 ms-1 in humans
True. Maximum velocity is up to 120 ms-1 in some A fibres.
40
The conduction velocity of an action potential:
| Is highest in pre-ganglionic autonomic fibres
False. Pre-ganglionic fibres are in group B, conducting at 3-14 ms-1.
41
These modalities correspond to their pathways:
| Proprioception via the dorsal columns
True. The dorsal columns transmit fine touch and proprioception.
42
These modalities correspond to their pathways:
| Temperature and pain via the contralateral spinothalamic tracts
True
43
These modalities correspond to their pathways:
| Fibres carrying fine touch sensation form the gracile and cuneate nuclei
True. Fine touch is transmitted in the posterior white column in the medial and lateral fasciculi, connecting to their respective cuneate and gracile nuclei.
44
These modalities correspond to their pathways:
| Proprioception and the pyramidal tract
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.
45
These modalities correspond to their pathways:
| Spinocerebellar tracts cross before reaching the cerebellum
False
46
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
False. Spinal shock ensues immediately after cord transection. This includes loss of reflexes. Hyper-reflexia occurs 2-6 weeks later.
47
Immediately after complete transection of the spinal cord the following features may be found below the lesion:
Urinary incontinence
True
48
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
False. Sensation will also be lost.
49
Immediately after complete transection of the spinal cord the following features may be found below the lesion:
Flaccid paralysis with loss of limb reflexes
True
50
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
False. Joint position sense is also lost.
51
Concerning pain pathways:
| The cell bodies of Aδ and C fibres reside within the dorsal root ganglion of the spinal cord
True. They are both first order neurones.
52
Concerning pain pathways:
| Aδ fibres synapse with cells of the substantia gelatinosa of the spinal cord
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).
53
Concerning pain pathways:
| C fibres synapse with cells in laminae II and III in the dorsal horn
True
54
Concerning pain pathways:
| Most ascending neurones are in the anterolateral columns
True. Most second order neurones cross within a few segments and ascend in the anterolateral columns (spinothalamic tract).
55
Concerning pain pathways:
| The substantia gelatinosa projects directly to higher levels
False
56
Spinal cord hemisection (The Brown-Sequard Syndrome) causes:
| Contralateral paralysis
False. The Brown-Sequard Syndrome causes ipsilateral paralysis.
57
Spinal cord hemisection (The Brown-Sequard Syndrome) causes:
| Ipsilateral loss of proprioception
True
58
Spinal cord hemisection (The Brown-Sequard Syndrome) causes:
| Ipsilateral loss of pain sensation
False. Pain and temperature sensation are lost contra-laterally.
59
Spinal cord hemisection (The Brown-Sequard Syndrome) causes:
| Contralateral loss of vibration sense
False. Vibration sense is carried by the ipsilateral dorsal columns.
60
Spinal cord hemisection (The Brown-Sequard Syndrome) causes:
| Contralateral loss of temperature sensation
False
61
A reflex action:
| May be carried out by glands, skeletal, smooth or cardiac muscle
True. The effector organs are usually muscles or glands which contract or secrete chemicals producing suitable responses.
62
A reflex action:
| Is influenced by higher centres in the brain
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.
63
A reflex action:
| Results from activity in at least two central nervous synapses in series
False. Monosynaptic reflexes (e.g. the stretch reflex) involve only one synapse.
64
A reflex action:
| May involve simultaneous relaxation of some skeletal muscles and contraction of others
True. During a stretch reflex, the muscles that antagonise the action of the muscles involved relax due to reciprocal innervation.
65
A reflex action:
| Can be either monosynaptic or polysynaptic
True
66
The knee jerk reflex:
| Starts with stimulation of receptors in the patellar tendon
False. Receptors are spindles in the muscle.
67
The knee jerk reflex:
| Is propagated through the lumbar segment L2
True. The knee jerk sensory fibre is a Ia fibre which synapses with an alpha motor neurone at the level of L2.
68
The knee jerk reflex:
| Has a reflex arc which involves a single interneurone
False. It is independent of higher centres although can be influenced by activity in higher centres.
69
The knee jerk reflex:
| Involves the femoral nerve
True. The femoral nerve supplies quadriceps.
70
The knee jerk reflex:
| Is preserved immediately after transection of the spinal cord at T6
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.
71
The vagus nerve:
| Has little direct effect on the strength of ventricular contraction
True
72
The vagus nerve:
| Contains afferent and efferent fibres
True
73
The vagus nerve:
| Contains parasympathetic post-ganglionic fibres
False. The preganglionic fibres of the parasympathetic division run almost to the organ innervated and then synapse in ganglia within the organ.
74
The vagus nerve:
| Contains fibres which regulate gastric acid secretion
True
75
The vagus nerve:
| Has a role in bladder emptying
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.
76
Concerning the sympathetic nervous system:
| Preganglionic fibres are all unmyelinated
False
77
Concerning the sympathetic nervous system:
| Synapses are in the lateral horn
False. The synapses are most frequently found in the sympathetic chains either side of the cord.
78
Concerning the sympathetic nervous system:
| It transmits sensation of pain
True
79
Concerning the sympathetic nervous system:
| Preganglionic fibres are shorter than postganglionic fibres
True
80
Concerning the sympathetic nervous system:
| It has adrenergic ganglia
False. Post ganglionic synapses use norepinephrine as the neurotransmitter. The only exception is the neurones terminating in sweat glands, which use Acetylcholine.
81
Vagal efferent stimulation results in:
| Decreased insulin secretion
False. Insulin secretion is increased.
82
Vagal efferent stimulation results in:
| Decreased physiological dead space
True. It also causes bronchoconstriction thus reducing anatomical and therefore physiological dead space.
83
Vagal efferent stimulation results in:
| Decreased gastrin secretion
False. Gastrin secretion is increased.
84
Vagal efferent stimulation results in:
| Increased gastric acid secretion
True
85
Vagal efferent stimulation results in:
| A reduction in bile production
False. Bile secretion is also increased.
86
The following receive only sympathetic innervation:
| Lacrimal glands
False. The lacrimal glands are one of the few organs receiving only parasympathetic fibres.
87
The following receive only sympathetic innervation:
| Piloerector Muscles
True. One of the few exceptions to dual sympathetic/parasympathetic control.
88
The following receive only sympathetic innervation:
| Adipose tissue
True. Sympathetic innervation allows for mobilisation of fat stores.
89
The following receive only sympathetic innervation:
| Juxtaglomerular apparatus
True
90
The following receive only sympathetic innervation:
| Pupils
False. Pupils are under dual control. Sympathetic system causes mydriasis (pupil dilatation) whereas parasympathetic stimulation results in miosis (pupil constriction).
91
The membrane potential of a nerve fibre:
| Is directly proportional to the diameter of the fibre
False
92
The membrane potential of a nerve fibre:
| Is measured conventionally as negative on the inside
True
93
The membrane potential of a nerve fibre:
| Represents an imbalance of charge across the two sided of a semi-permeable membrane
True
94
The membrane potential of a nerve fibre:
| Reverses its polaity during an action potential
True
95
The membrane potential of a nerve fibre:
| Can be calculated from the nernst equation
False
96
Compared with plasma, CSF contains:
| Less Sodium
True
97
Compared with plasma, CSF contains:
| Lower osmolality
False
98
Compared with plasma, CSF contains:
| More hydrogen ions
True
99
Compared with plasma, CSF contains:
| A higher PCo2
True
100
Compared with plasma, CSF contains:
| More urea
False
101
Concerning cerebral blood flow:
| Blood flow in the grey matter may be twice that in the white matter
True
102
Concerning cerebral blood flow:
| Is inversely proportional to PaCO2
False
103
Concerning cerebral blood flow:
| Is predominantly provided by the external carotid artery
False
104
Concerning cerebral blood flow:
| Is reduced with acidosis
False
105
Concerning cerebral blood flow:
| It is equal to 10% of cardiac output
False
106
The knee jerk reflex:
| Is due to stimulation of receptors in the patellar tendon
False
107
The knee jerk reflex:
| Has a reflex arc which involves a single interneurone
False
108
The knee jerk reflex:
| The afferent pathway is via AA delta fibres
False
109
The knee jerk reflex:
| Hypereflexia of the patella is known as westphal's sign
False
110
The knee jerk reflex:
| is abolished immediately after transection of the spinal cord at T6
True
111
These modalities correspond to their correct pathways:
| Temperature and pain via the ipsilateral spinothalamic tracts
False
112
These modalities correspond to their correct pathways:
| Fibres subserving fine touch from the gracile and cuneate nuclei
True
113
These modalities correspond to their correct pathways:
| Proproception via the dorsal columns
True
114
These modalities correspond to their correct pathways:
| Spinocerebellar tracts relay information from muscles
True
115
These modalities correspond to their correct pathways:
| Pain and the spinotectal tract
True
116
When the nerve cell membrane is depolarised:
| Sodium permeability falls slowly, producing an action potential
False
117
When the nerve cell membrane is depolarised:
| Sodium permeability is raised until the resting membrane potential is restored
False
118
When the nerve cell membrane is depolarised:
| Increased calcium permeability produces a plateau phase
False
119
When the nerve cell membrane is depolarised:
| The change in sodium permeability is directly responsible for impulse transmission
True
120
When the nerve cell membrane is depolarised:
| Sodium efflux is self limiting
True
121
The nerve action potential:
| Transmission is saltatory between the nodes of ranvier
True
122
The nerve action potential:
| Is conducted slower in the myelinated fibres
False
123
The nerve action potential:
| Is propogated exponentially
False
124
The nerve action potential:
| Is approx 35mV above resting potention
False
125
The nerve action potential:
| Is initiated by sodium influx
True
126
In complete cord transection:
| Arterial blood pressure becomes labile
True
127
In complete cord transection:
| Autonomic hypereflexia occurs within a few days
False
128
In complete cord transection:
| Tendon reflexes are the first to recover
False
129
In complete cord transection:
| Recovery of reflexes occurs at around 6 months
False
130
In complete cord transection:
| There is a total loss in sensation from dermatomes below the level of injury
True
131
Cerebral bloodflow:
| A high Pa O2 causes cerebral vasoconstriction
True
132
Cerebral bloodflow:
| The normal jugular venous saturation is about 65%
True
133
Cerebral bloodflow:
| Can be estimated by doppler
True
134
Cerebral bloodflow:
| acidosis induces cerebral vasodilation is independent of PaCO2
True
135
Cerebral bloodflow:
| A decrease in arterial pressure causes vasoconstriction of cerebral vessels
False
136
The conduction velocity along a nerve:
| Is increased by myelination
True
137
The conduction velocity along a nerve:
| Increases when the serum potassium is low
False
138
The conduction velocity along a nerve:
| Increases with diameter
True
139
The conduction velocity along a nerve:
| Is greater in delta than alpha fibres
False
140
The conduction velocity along a nerve:
| Is greater in motor than in sensory nerve
True
141
The action potential:
| Depolarization is caused by the transfer of sodium ions across the membrane
True
142
The action potential:
| In the resting state the potential inside the nerve fibre is +85mV
False
143
The action potential:
| Is generated by differing ionic concentrations of sodium and potassium
True
144
The action potential:
| Occurs when the membrane depolarises by 15mV
True
145
The action potential:
| Has 4 phases
False
146
Stimulation of the parasympathetic nervous system causes:
| Bladder relaxation
False
147
Stimulation of the parasympathetic nervous system causes:
| Gall-bladder contraction
True
148
Stimulation of the parasympathetic nervous system causes:
| Bronchodilation
False
149
Stimulation of the parasympathetic nervous system causes:
| Miosis
True
150
Stimulation of the parasympathetic nervous system causes:
| Decreased insulin secretion
False
151
Concerning intracranial pressure:
| Tonsillar (cerebellar) herniation causes ipsilateral pupillary dilation
False
152
Concerning intracranial pressure:
| The effect of hypocapnia-induced cerebral vasoconstriction is maintaines for 12 hours or more
False
153
Concerning intracranial pressure:
| Normal ICP is 10-20 mmHg
False
154
Concerning intracranial pressure:
| ICP increases linearly with increasing cerebral blood volume
False
155
Concerning intracranial pressure:
| Lundberg B pressure waves may be a normal finding
False
156
The following are parasympathetic ganglia:
| Ciliary ganglion
True
157
The following are parasympathetic ganglia:
| Otic Ganglian
True
158
The following are parasympathetic ganglia:
| Stellate ganglion
False
159
The following are parasympathetic ganglia:
| Gasserian ganglion
False
160
The following are parasympathetic ganglia:
| Coeliac ganglion
False
161
The chemical mediator released at the following sites is acetylcholine:
Parasympathetic preganglionic neurones
True
162
The chemical mediator released at the following sites is acetylcholine:
Parasympathetic postganglionic neurones
True
163
The chemical mediator released at the following sites is acetylcholine:
Sympathetic postganglionic neurones which innervate the heart
False
164
The chemical mediator released at the following sites is acetylcholine:
Sympathetic preganglionic neurones
True
165
The chemical mediator released at the following sites is acetylcholine:
Sympathetic postganglionic neurones which innervate sweat glands
True
166
The autoregulation of cerebral blood flow:
| Curve shows a shift to the left in chronic hypertension
False
167
The autoregulation of cerebral blood flow:
| Is maintained under hypoxic conditions
False
168
The autoregulation of cerebral blood flow:
| Remains constant over a range of systolic blood pressures from 60-140 mmHg
False
169
The autoregulation of cerebral blood flow:
| Is impaired in hypercapnia
True
170
The autoregulation of cerebral blood flow:
| Is altered in the acute phase following a subarachnoid haemorrhage
True
171
The pathways of pain sensation include:
| C fibres which release histamine and serotonin
False
172
The pathways of pain sensation include:
| A-delta fibres which terminate in lamina 1 of the dorsal horn
True
173
The pathways of pain sensation include:
| A-gamma fibres synapsing in the dorsal horn
False
174
The pathways of pain sensation include:
| Second order neurones which ascend in the ipsilateral spinothalamic tracts
False
175
The pathways of pain sensation include:
| Descending pathways in the dorsolateral columns
True
176
In the autonomic nervous system:
| Parasympathetic nervous system stimulation produces coronary vasodilation
True
177
The pathways of pain sensation include:
| The stellate ganglia impair myocardial contractility
False
178
The pathways of pain sensation include:
| Post-ganglionic sympathetic nerves increase catecholamine releases from the adrenal glands
False
179
The pathways of pain sensation include:
| All preganglionic neurones are cholinergic
True
180
The pathways of pain sensation include:
| Alpha-2 stimulation modifies intracellular cGMP levels
False
181
Acetylcholine:
| Is the neurotransmitter at all parasympathetic postganglionic nerve endings
True
182
Acetylcholine:
| Is generated from choline synthesized with axoplasm
False
183
Acetylcholine:
| Its synthesis is catalysed by the enzyme choline acetylesterase
False
184
Acetylcholine:
| Is an ester
True
185
Acetylcholine:
| Raises the membrane permeability to sodium and calcium in the heart
False
186
Regarding the cerebral circulation:
| The circle of willis is formed from the internal carotid and vertebral arteries only
True
187
Regarding the cerebral circulation:
| The middle cerebral artery is most commonly affected by a CVA
True
188
Regarding the cerebral circulation:
| The anterior spinal artery is a branch of the vertebral artery
True
189
Regarding the cerebral circulation:
| The posterior spinal artery is a branch of the vertebral artery
True
190
Regarding the cerebral circulation:
| The anterior cerebral artery supplies the superior and medial parts of the cerebral hemisphere
True
191
Concerning the enteric nervous system:
| It contains pre-ganglionic cholinergic fibres
True. Generally, the parasympathetic supply to the GIT is via pre-ganglionic vagal fibres.
192
Concerning the enteric nervous system:
| Vagal fibres are post-ganglionic
False.
193
Concerning the enteric nervous system:
| It contains post-ganglionic sympathetic fibres
True. The sympathetic supply is post-ganglionic, but may end on cholinergic neurones or on smooth muscle fibres directly.
194
Concerning the enteric nervous system:
| Many sympathetic fibres end on cholinergic neurones
True
195
Concerning the enteric nervous system:
| Many sympathetic fibres end directly on intestinal smooth muscle
True
196
Concerning nerve conduction:
| A-delta fibres are the slowest as they are unmyelinated
False. A and B fibres are myelinated and therefore have fast conduction velocities due to saltatory conduction.
197
Concerning nerve conduction:
| A-beta fibres exhibit saltatory conduction
True.
198
Concerning nerve conduction:
| C fibres are myelinated
False.
199
Concerning nerve conduction:
| A-alpha fibres conduct at 30-70 m/s
False. A-alpha fibres conduct at 70-120 m/s
200
Concerning nerve conduction:
| A-delta fibres provide sensory innervation to muscle spindles.
False. But A-gamma fibres provide motor supply to muscle spindles.
201
Hemisection of the spinal cord causes:
| Ipsilateral paralysis
True
202
Hemisection of the spinal cord causes:
| Ipsilateral loss of proprioception
True
203
Hemisection of the spinal cord causes:
| Contralateral loss of pain sensation
True
204
Hemisection of the spinal cord causes:
| Ipsilateral loss of vibration sense
True
205
Hemisection of the spinal cord causes:
| Contralateral loss of temperature sensation
True
206
Concerning synaptic transmission:
| The synaptic cleft is 100 nm wide
False. The synaptic cleft is 30-50 nm wide.
207
Concerning synaptic transmission:
| Temporal summation may occur
True. Summation of excitatory postsynaptic potentials may be both spatial and temporal.
208
Concerning synaptic transmission:
| Synaptic delay is normally 0.1 ms
False. Synaptic delay is normally 0.5 ms.
209
Concerning synaptic transmission:
| IPSPs are depolarising
False. IPSPs are hyperpolarising.
210
Concerning synaptic transmission:
| EPSPs are depolarising
True.
211
Concerning the knee jerk reflex:
| It is monosynaptic
True
212
Concerning the knee jerk reflex:
| The synaptic transmitter is glutamate
True
213
Concerning the knee jerk reflex:
| The sensory organ is the muscle spindle
True
214
Concerning the knee jerk reflex:
| It involves spinal roots L2,3,4
True
215
Concerning the knee jerk reflex:
| Glycine inhibition occurs in fibres to antagonistic muscles.
True
216
Concerning the visual pathway:
| Optic tract lesions will cause a bitemporal hemianopia
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
Concerning the visual pathway:
| Optic chiasm lesions will cause a bitemporal hemianopia
True. As at the Optic chiasm, temporal fibres cross the midline.
218
Concerning the visual pathway:
| Occipital lesions may spare the macula
True. As the macula fibres are separated from the rest of the cortex subserving vision.
219
Concerning the visual pathway:
| Optic nerve lesions will cause bilateral loss of vision
False. They will cause unilateral loss of vision.
220
Concerning the visual pathway:
| Field defects start as scotomas.
True. These are small areas of visual loss.
221
Concerning pain pathways:
| A-delta have cell bodies within the vental root ganglion of the spinal cord
False. A-delta have cell bodies within the dorsal root ganglia.
222
Concerning pain pathways:
| A-delta fibres synapse with cells of the substantia gelatinosa of the spinal cord
False. A-delta fibres synapse with cells in laminae I and V of the dorsal horn.
223
Concerning pain pathways:
| C fibres synapse with cells in laminae IV and V in the dorsal horn
False. C fibres synapse with cells in laminae II and III in the dorsal horn.
224
Concerning pain pathways:
| Most ascending neurones are in the anterolateral columns
True. Most second order neurones cross within a few segments and ascend in the anterolateral columns (spinothalamic tract).
225
Concerning pain pathways:
| The substantia gelatinosa projects directly to higher levels
False. The SG does not project directly to higher levels but contains multiple interneurones involved in pain modification.
226
Concerning sensory receptors:
| Meissners corpuscles are associated with nociception
False. Meissners corpuscles are associated with touch.
227
Concerning sensory receptors:
| Ruffini corpuscles are associated with proprioception
True.
228
Concerning sensory receptors:
| Pacinian corpuscles are associated with vibration
True. Pacinian corpuscles are associated with proprioception and vibration.
229
Concerning sensory receptors:
| Ruffini corpuscles are associated with nociception
False. Free nerve endings are associated with nociception
230
Concerning sensory receptors:
| Pacinian corpuscles are associated with proprioception
True. Pacinian corpuscles are associated with proprioception and vibration.
231
Concerning the cranial nerves:
| VII provides taste sensation to the posterior third of the tongue
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
Concerning the cranial nerves:
| V provides motor fibres to the jaw and tongue
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
Concerning the cranial nerves:
| IV innervates the inferior oblique muscle
False. IV innervates the superior oblique muscle.
234
Concerning the cranial nerves:
| III performs most eye movements
True. With IV and VI supplying superior oblque (to look down and inward) and lateral rectus (abduction) respectively.
235
Concerning the cranial nerves:
| XII provides motor innervation to palatoglossus
False. XII innervates all tongue muscles except palatoglossus, which is innervated by X.
236
In the EEG, delta waves occur:
| With increased cortical activity
False
237
In the EEG, delta waves occur:
| Normally during sleep
True
238
In the EEG, delta waves occur:
| Prominently over the frontal area
False
| beta waves prominent over the frontal area.
239
In the EEG, delta waves occur:
| Upon closing the eyes
False
| Alpha waves are prominent on closing the eyes or with increased cortical activity
240
In the EEG, delta waves occur:
| Normally in children
True
