Neurology Flashcards
1
Q
What is the most common pathophysiology of stroke?
A
Blockage of blood vessel.
2
Q
Haemorrhage is often associated with…
A
Hypertension
3
Q
What causes changes in membrane potential?
A
The electrochemical and concentration gradients.
4
Q
How are ion channels generally closed?
A
By hyperpolarisation/ repolarisation
5
Q
What returns a cell to its resting membrane potential?
A
Potassium efflux from cell.
6
Q
What is Saltatory conduction?
A
Electrical conduction moving from one node of ranvier to another to speed up conduction.
7
Q
Name two factors which affect conduction velocity
A
Myelination and axon diameter
8
Q
Will conduction velocity be faster in a smaller diameter or a larger diameter?
A
Larger; less internal resistance
9
Q
What is the main issues in Multiple Sclerosis? Apart from this what else may you see under a microscope?
A
Demyelination of axons. Can also see a lower cell density.
10
Q
What is the neuromuscular junction?
A
A specialised synapse between a motor neuron and a muscle fibre.
11
Q
What is the characteristic pathology of Multiple Sclerosis?
A
Inflammation and Loss of myelin within the CNS.
12
Q
Are receptors on the pre-synaptic or post synaptic membrane?
A
The post-synaptic membrane
13
Q
Which is the neurotransmitter for voluntary striated muscle?
A
Acetylcholine
14
Q
What are MEPPs?
A
Miniature end-plate potentials = Small potentials at rest caused by individual vesicles releasing ACh.
15
Q
What is the name of the cytoplasm within the muscle?
A
The sarcoplasm
16
Q
What is the sarcolemma?
A
The plasma membrane which covers the myofibre.
17
Q
Estimate the diameter of the myofibre.
A
1-2um.
18
Q
What is another name for the dark band?
A
The A band
19
Q
What is another name for the light band?
A
The I band
20
Q
Does the A band’s length change during contraction?
A
No. The A band remains at the same length.
21
Q
What is the name of the neuromuscular disease which does not allow ACh to be released into the synaptic cleft?
A
Botulism.
22
Q
Which is the neuromuscular disease which causes antibodies to bind to ACh receptors on the post synaptic cleft?
A
Myasthenia Gravis
23
Q
What is Lambert Eaton Myasthenia syndrome?
A
An autoimmune disorder where channels at the pre-synaptic cleft do not allow calcium in.
24
Q
What is an electromyogram?
A
Records action potentials in the skeletal muscle.
25
What is Lambert-Eaton Myasthenic syndrome associated with?
Lung Cancer
26
Define Multiple Sclerosis
A chronic inflammatory disease of the CNS causing oligodendroglial and axonal pathology.
27
What two diagnostic components are involved in diagnosing Multiple Sclerosis?
MRI and CSF analysis to show inflammation
28
Name x5 neurological diseases
Stroke, Multiple Sclerosis, Epilepsy, Parkinson's, Carpel Tunnel syndrome
29
A 50 year old man who smokes and has high blood pressure collapses at work. He is unable to speak, and move the right side of his face. He is unable to move his right arm or leg. Where is the problem?
Brain
30
Name the two types of stroke and which is more common?
Ischaemic - 80%
| Haemorrhagic - 20%
31
What is the word used to describe symptoms felt on the opposite side of the brain legion?
Contralateral
32
Which side of the brain is responsible for language?
The left side
33
Which artery is most commonly affected in strokes?
The Middle cerebral artery
34
What sign is most commonly seen in middle cerebral artery strokes?
Weakness and loss of sensation contralaterally
35
What sign is most commonly seen in posterior cerebral artery strokes?
Visual Loss contralaterally
36
What sign is most commonly seen in anterior cerebral artery strokes?
Leg weakness contralaterally
37
Which part of the brain is affected in Parkinson's Disease?
The Basal Ganglia
38
Name x3 clinical features of Parkinson's Disease
Rigidity, Tremor and Bradykinesia
39
What does bradykinesia mean?
Reduced movement
40
What is the name of the chemical affected in Parkinson's which does not cross the blood brain barrier?
Dopamine
41
Absent reflexes are associated with a lesion situated where?
The Lower motor neurone
42
Present reflexes are associated with a lesion situated where?
The Upper motor neurone
43
Name x2 common causes of acute neuromuscular weakness
Guillain Barre Syndrome and Acute Inflammatory Demyelinating Polyneuropathy (GBS/AIDP)
44
To measure Cerebrospinal fluid, what diagnostic method is used?
Lumbar puncture
45
From which part of the brain do seizures arise?
The Cerebral cortex
46
What is the cause of epilepsy?
A decrease in the inhibitory action of GABA or an increase in excitatory action of Glutamate.
47
What are anticonvulsants?
A group of treatments used to prevent seizures e.g. glutamate receptor antagonist.
48
Name x5 anti-epileptic drugs
Valproate, Phenobarbital, Benzodiazepines, Vigabatrin, Tiagabine.
49
Which class of anti-epileptic drugs enhance GABA action
Benzodiazepines e.g. Diazepam and Phenoarbitals.
50
What is the mechanism of action of Vigabatrin?
Inhibits GABA transaminase
51
What is the mechanism of action of Tiagabine?
Inhibits GABA reuptake
52
What is the mechanism of action of Phenobarbital?
Enhanced GABA action
53
What is the mechanism of action of Valproate?
Weak effect on GABA transaminase and Na+ channels
54
Which anti-epileptic medications are used on all forms of epilepsy?
Benzodiazepines and Vigabatrin.
55
Which anti-epileptic medication can be used in all forms of epilepsy apart from absence seizures?
Phenoarbital
56
Which anti-epileptic medication is used on focal seizures?
Tiagabine
57
What is the name of the enzyme which converts GABA to glutamate?
GABA Transaminase
58
What are spines?
Protrusions which sit on the dendrite. These protrusions receive the majority of synapses.
59
What are axons made up of?
Intermediate filaments and microtubules
60
What are the three types of neurone synapses?
Axo-dendritic, axo-somatic and axo-axonic.
61
What is the range length of an axon in humans?
um-1m
62
What is the cytoskeleton made up of?
Microfilaments, intermediate filaments and microtubules.
63
What are the differences between Golgi I multipolar and Golgi II multipolar neurones?
Golgi I multipolar neurones = long axons
| Golgi II multipolar neurones = short axons
64
What is the group name of astrocytes, schwann cells, oligodendrocytes and microglia
Neuroglia
65
Which is the most abundant nerve cell in the human body?
Astrocytes
66
Give x5 functions of astrocytes
1. Formation of blood-brain barrier
2. Removal of neurotransmitters
3. Axonal Growth during development
4. Glial Scar formation
5. K+ buffering
67
Which receptors on astrocytes allow glutamate in?
EAAT-2 receptors
68
Which are the myelin forming cells of the CNS?
Oligodendrocytes
69
Describe the structure of oligodendrocytes
Small nuclei, few thin processes, many ER and GA
70
What is the main function of microglia?
Immune function. Present antigens to invading immune cells, act as macrophages.
71
Which is the phagocytic nerve cell?
The microglia
72
Which are the myelin forming cells of the PNS?
The Schwann cells
73
What is the average length of time between two action potentials?
2ms
74
Name the three stages of synaptic transmission
1. Biosynthesis, packaging and release of neurotransmitter
2. Receptor activation
3. Inactivation
75
Glutamate and GABA are examples of what type of neurotransmitter?
Amino acid neurotransmitter.
| Noradrenaline = amine
76
Which ion is essential for neurotransmitter release?
Ca2+
77
Approximately how many molecules are there per synaptic vesicle?
4000- 10,000
78
How do vesicles release neurotransmitters into the synaptic cleft?
The vesicle fuses with the membrane and release their neurotransmitters via exocytosis.
79
How do vesicles rapidly release neurotransmitters?
Interaction between the synaptic vesicle and synaptic membrane proteins = rapid response. The vesicle is docked in a 'prime' zone close to Calcium channel. Entry of calcium through channel activates a sensor in the protein complex.
80
What is the protein complex made up of?
The synaptic vesicle, proteins and membrane.
81
Which transmission is faster - impulses through ion channel receptors or G-Protein coupled receptors?
Ion channel receptors
82
ACh at nicotine receptors moves through which type of receptor?
Ion channel receptors
83
ACh at muscarinic receptors moves through which type of receptor?
G-Protein coupled receptors
84
Compare the ion flow through Glutamate receptors Vs GABA receptors
```
Glutamate = Na+ flow
GABA = Cl- flow
```
85
GLUR, AMPA and NMDA receptors are examples of what type of receptor?
Glutamate receptors
86
Which receptor is the fast excitatory synapse receptor?
AMPA
87
Which receptor is the slow excitatory synapse receptor?
NMDA
88
Where are glutamate and GABA transporters found?
On the Glial cell
89
What is the name of the glutamate transporter on the glial cell?
EAAT - Excitatory amino acid transporter
90
What does glutamate break down to?
Glutamine
91
What is the name of the GABA transporter on the glial cell?
GAT - GABA Transporter
92
What chemical does GABA break down to and by which enzyme?
Succinate semialdehyde (SSA) via GABA Transaminase.
93
What is the name of the enzyme which breaks Glutamate down to GABA?
Glutamic acid decarboxylase
94
Describe the structure of the GABA receptor.
Pentameric. Different binding sites for barbiturates, benzodiazepines, GABA, ethanol and steroids.
95
The sympathetic and parasympathetic system are parts of which type of control?
Autonomic control
96
How is the peripheral system divided?
Somatic control and autonomic control
97
Where is the visual cortex?
In the occipital lobe
98
Where is the somatosensory cortex?
In the parietal lobe
99
Which is the longest cranial nerve?
The vagus nerve
100
What is the name of the connective tissue that covers the brain?
The meninges
101
Name the 12 cranial nerves
Olfactory I, Optic II, Oculomotor III, Trochlear IV, Trigeminal V, Abducens VI, Facial VII, Vestibulocochlear VIII, Glossopharyngeal IX, Vagus X, Accessory XI, Hypoglossal XII.
102
Which are the three layers of the meninges?
Dura mater, arachnoid, subarachnoid space.
103
What is another word for anterior?
Ventral
104
Which is the afferent pathway in the spinal cord?
The Dorsal horn
105
What is the cell body of a neurone also known as?
The soma
106
Can a nerve impulse travel down a demyelinated neurone?
Yes albeit much slower than a myelinated neurone.
107
Give an example of an unmyelinated neurone.
Nociceptive (pain) fibres
108
At what membrane potential do potassium channels open to repolarise the cell?
+40mV
109
Which nerve system can regenerate more easily?
The Peripheral nervous system
110
Which are the two sensory pathways?
The Dorsal column-medial lemniscus pathway +
| Spinothalamic pathway
111
Which are the two motor pathways?
Lateral corticospinal tract + Vestibulospinal tract
112
Which pathway conveys fine- touch, vibration and discrimination?
The Dorsal column medial lemniscus pathway
113
What is the difference between the dorsal column medial lemniscus pathway and the spinothalamic pathway?
Dorsal column medial lemniscus = enters spinal column and leaves on same side.
Spinothalamic = enters spinal column and leaves on opposite side of the body.
114
What is the word for the same side of the body?
Ipsilateral
115
Is the vestibulospinal tract contralateral or ipsilateral?
Ipsilateral
116
What is the neuromuscular junction?
A specialised synapse between a motor neurone and a muscle fibre
117
What is the typical diameter of the chemical synapse?
10-50 nm
118
'Bouton' refers to....
the pre-synaptic terminal
119
Which is the neurotransmitter for voluntary striated muscle?
Acetylcholine
120
What is electromyography?
The recording of action potentials within muscle fibres.
121
Define twitch
A short, sudden jerking or convulsive movement
122
Define tetanus
Prolonged contraction of a muscle due to a rapidly repeated stimuli.
123
Define summation
The additive effect of several electrical impulses at a neuromuscular junction.
124
Define electromyogram
Measures action potentials in skeletal muscle fibres.
125
What is the difference between intracellular and extracellular electromyography?
```
Intracellular = one electrode inside the cell and the other outside.
Extracellular = both electrodes are outside of the muscle fibre.
```
126
What does GABA break down to?
Succinate semialdehyde
127
Explain how a resting membrane potential can arise across a selectively permeable membrane.
Diffusion of ions through a selectively permeable membrane
=generates membrane potential.
128
What is the typical resting potential of a neuron?
-70mV
129
Define electrochemical equilibrium
When electrical forces balance diffusion forces and prevent further diffusion across membranes.
130
Define equilibrium potential
The potential at which the electrochemical equilibrium has been reached. It prevents further diffusion.
131
What is the Nernst equation?
Used to calculate equilibrium potential.
132
What is the typical value of potassium inside and outside of the cell?
Intracellular K+ = 150mM
| Extracellular K+ = 5mM
133
What is the typical value of sodium inside and outside of the cell?
Intracellular Na+ = 10mM
| Extracellular Na+ = 150mM
134
Why does potassium exert a stronger affect than sodium on the resting membrane potential?
The membrane is more permeable to potassium.
135
What is an action potential?
Nerve impulses which travel along an axon upon stimulus in an excitable cell.
136
Define threshold
Once this potential is reached an action potential is triggered
137
Define refractory period
```
Absolute = No action potential can be stimulated - even with a strong stimulus. Na+ inactivation gate is closed.
Relative= Na+ inactivation gate is open. The Na+ activation gate is closed meaning a stronger stimulus is needed, but if strong enough CAN generate action potential.
```
Refractive state = unresponsiveness to threshold depolarization
138
Define 'all or nothing' behaviour
Once triggered, a full sized action potential occurs
139
Define depolarisation
The department becomes less negative.
140
Define repolarisation
The department becomes more negative - usually caused by K+ efflux.
141
Define hyperpolarisation
The department becomes more negative than at its resting membrane potential.
142
Define saltatory conduction
Action potential jumps across nodes of ranvier enabling faster propagation of nerve impulses.
143
What is a voltage-gated channel?
A channel which allows ions through and is activated upon sodium influx.????????
144
Across an axon, do GRADED potentials continue at the same speed?
No. GRADED potentials work via decremental spread meaning they become less powerful further along the axon. Action potentials maintain speed.
145
What is positive feedback?
A continuous loop e.g. When there is depolarisation of a cell, sodium channels are activated increasing Na+ permeability allowing Na+ influx which causes further depolarisation.
146
How does the cell return to its resting membrane potential after hyperpolarisation?
Some K+ channels close, making the cell a little less negative.
147
Recall the size and duration of a neuronal action potential
Large diameter, myelinated = 120m/s
| Smaller diameter, unmyelinated = 1m/s
148
What is regenerative conduction
The positive feedback loop between sodium voltage gated channel activation, increased sodium permeability, sodium influx and depolarisation of the cell.
149
Name x3 conditions which may affect conduction along the axon
Demyelination e.g. multiple sclerosis
Smaller axon diameter
Drugs, cold, anoxia
150
What is one key thing to remember about the upstroke of the action potential?
Both Na+ and K+ channels are open but the Na+ influx is QUICK whereas K+ influx is slow. More Na+ coming in than K+ leaving.
151
When is the membrane potential closer to the sodium equilibrium potential?
During depolarisation (the upstroke).
152
When is the membrane potential closer to the potassium equilibrium potential?
During repolarisation/ hyperpolarisation.
153
How many cervical, thoracic, lumbar, sacral and coccyx vertebrae are there?
7, 12, 5, 5, 4
154
How many spinal vertebrae are there in total?
33
155
How many cervical, thoracic, lumbar, sacral and coccyx nerves are there?
8, 12, 5, 5, 1
156
How many spinal nerves are there in total?
31
157
What are the functions of the dorsal and ventral horns?
The dorsal horn receives sensory information from the body. The ventral horn carries signals away from the CNS and toward the limbs/ organs.
158
What is one way to check if an individual has a higher intracranial pressure?
Check behind the eyes for papilloedema.
159
What is the level of a lumbar puncture?
Adults: L3-L4
Children: L4-L5
160
What is the difference between bacterial and viral meningitis?
```
Bacterial = High protein, low glucose
Viral = Low protein, normal/high glucose
```
161
How would you distinguish between an epitdural and subdural haemorrhage?
Epidural is bleeding between the dura mater and the skull.
Subdural is bleeding between the dura mater and the arachnoid.
Epidural is arterial (expands with arterial blood), subdural is venous.
162
How may hydrocephalus be treated?
Drain cerebrospinal fluid from the head.
163
Which part of the brain passes through the foramen ovale?
The spinal cord.
164
The dorsal ramus supplies which region?
The posterior region
165
The ventral ramus supplies which region?
The anterior region
166
What is the difference between myotomes and dermatomes?
Dermatomes have a single supply whereas myotomes have more than one supply.
167
If there were a lesion at the mixed spinal nerve would you see weakness or paralysis?
Weakness; not paralysis as the myotome has more than one supply.
168
Paralysis is seen in what type of lesion?
A lesion affecting the motor (ventral) nerve.
169
Weakness is seen in what type of lesion?
A lesion affecting the sensory (dorsal) nerve
170
What do you find a lot of in the node of ranvier?
Na+ channels
171
Describe the sequence of peripheral denervation to regeneration.
Normal - destroyed axon and arriving phagocytes - demyelination and axon budding off 'sprouts' to regeneration of axon to myelin reformation.
172
Which part of the brain lies in the anterior cranial fossa?
The frontal lobe
173
Which part of the brain lies in the middle cranial fossa?
Parietal and temporal lobe
174
Which part of the brain lies in the posterior cranial fossa?
Brainstem and the cerebellum
175
Which part of the brain lies directly above the body of the sphenoid bone?
The hypothalamus
176
Which part of the brain passes through the foramen magnum?
The spinal cord
177
Nifedipine is an example of what type of drug?
Calcium channel antagonist
178
Which channel is responsible for bringing the ventricular myocyte fully back to its resting membrane potential?
IK1.
179
What is a difference between T type and L type calcium channels?
T type channels are activated at more negative potentials than L type channels.
180
Name x3 differences between the action potential in the SAN compared with the ventricular myocyte.
SAN does not have a resting membrane potential.
Ventricular myocyte has IK1 channel, ventricular myocyte does not.
Depolarisation in SAN is mainly due to Ca2+, in ventricular myocyte = mainly due to Na+ and so slower upstroke in SAN.
181
Chronotropy relates to what?
Heart rate
182
Inotropy relates to what?
Contractility
183
Lusitropy relates to what?
Myocardial relaxation
184
What is special about the atrioventricular node?
It allows a small delay of conduction following atrial contraction.
185
What are the function of gap junctions within the cardiac myocytes?
Allow current to easily leak from cell to another and reduces membrane resistance between cells.
186
Intercellular communication and impulse conduction rely on what?
Gap Junctions
187
The brainstem contains how many nuclei of the cranial nerves?
10 out of the 12.
188
Which part of the brain is affected in Parkinson's Disease?
The substantia nigra of the midbrain.
189
What is the role of the thalamus?
Emotion and motor reponse
190
What is the role of the hypothalamus?
Regulates temperature, hunger and thirst.
191
What are the 3 layers of the meninges from inward out?
Pia mater, (subarachnoid space), Arachnoid mater, Dura mater
192
Which structure produces the cerebrospinal fluid?
The choroid plexus
193
What is the difference between the cerebrospinal fluid and plasma?
The CSF has lower protein content, lower glucose and lower pH. CSF also has higher Cl- and higher Mg2+.
194
Name x4 functions of the Cerebrospinal fluid.
Cushioning, nutrition, removal of waste and immune function.
195
What is a ganglion?
A collection of cell bodies.
196
What are the two divisions of the motor response in the peripheral nervous system?
The somatic and the autonomic nervous system.
197
The propagation speed of a nerve impulse is related to its stimulus strength. True or false?
False.
198
Why do myelinated fibres conduct nerve impulses faster?
| Larger fibres?
Myelinated fibres conduct nerve impulses faster due to saltatory conduction. Larger fibres conduct nerve impulses faster due to there being less resistance.
199
Order the nerve fibres in order of size and therefore propagation speed.
A > B > C. A is the fastest at 130m/s. B = 15m/s, C = 2m/s.
200
What are the 3 divisions of the autonomic system?
Sympathetic, parasympathetic and enteric
201
What is the function of the autonomic system?
Maintains homeostasis of internal environment and involuntary control of viscera and glands.
202
In the ANS, a sequence of how many neurones are there between the CNS and innervated structure?
2; Preganglionic neuron to ganglion to postganglionic fibre.
203
Which CNS structure provides high level regulation of autonomic activity?
The hypothalamus
204
Where do neurones synapse in the sympathetic system?
At the paravertebral ganglia
205
Where do neurones synapse in the parasympathetic system?
At the ganglia close to the organ in which they innervate.
206
Where is there NO synapse for sympathetic innervation?
The adrenal gland
207
Where along the spinal cord do the pre-ganglionic neurons emerge from in the sympathetic system?
The thoracic and upper lumbar regions. (T1-T12) and (L1-L3).
208
Which structures are innervated for the sympathetic and parasympathetic system?
The eye, blood vessels, glands, mucosal membranes, thoracic, abdominal and pelvic viscera.
209
Which has a longer pre-ganglionic neurone - the sympathetic or parasympathetic?
The parasympathetic
210
From what spinal cord segments do the preganglionic parasympathetic neurones emerge from?
Cranio-sacral regions. (S2-S4).
211
Which cranial nerves are associated with the parasympathetic nervous system?
The vagus nerve and the glossopharyngeal nerve
212
Which are the cranial nerves?
III, VII, IX and X – Oculomotor, facial, glossopharyngeal and vagus.
213
Why do you think the anatomy of the symp. & parasymp. nervous systems differs?
The sympathetic system has a mass response around the body whereas the parasympathetic response is more localised and discrete which conserves energy.
214
What are the ramus communicans?
The ramus communicans connects the spinal nerves to the sympathetic chain.
215
What is the difference between the white and grey ramus communicans?
White ramus communicans is associated with the pre-ganglionic axon in the sympathetic system
Grey ramus communicans is associated with the post-ganglionic axon in the sympathetic system
216
Which is cranial nerve III?
Oculomotor nerve
217
What is 'accomodation' within the eye?
A reflex action of the eye where lens and pupil shape change.
218
What is 'accomodation' within the eye?
A reflex action of the eye where lens, ciliary muscle and pupil shape change.
219
Where does the posterior ramus innervate?
The back
220
Which is larger - the anterior or posterior ramus?
The posterior ramus
221
Where does the anterior ramus innervate?
The rest of the body apart from the head - which is innervated predominantly by cranial nerves.
222
Give x5 functions of the vascular endothelium.
```
Vascular tone
Prevents thrombosis
Absorption and secretion
Barrier
Growth
```
223
Where does the sensory neuron derive from?
Neural crest cells
224
Which fibres are unmyelinated?
C fibres.
225
The UMN is part of which system compared with the LMN?
```
UMN = central nervous system
LMN = peripheral nervous system
```
226
Where do Lower motor neurones (LMN) derive from?
The basal plate
227
The peripheral nervous system consists of how many nerves?
43; 12 cranial nerves + 31 spinal nerves.
228
How many neurones in the ANS compared with the SNS?
Autonomic nervous system = 3
| Somatic nervous system = 2
229
Where does the hypothalamic nuclei go to?
Either the spinal cord or the brainstem nuclei.
230
In which nerve is no ganglia found - only a pre-synaptic and post-synaptic neurone?
The vagus nerve
231
From where do pre-synaptic neurones derive?
The basal plate (in the spinal cord).
232
From where do post-synaptic neurones derive?
The neural crest
