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Answers to questions from notes – Neuroscience
1. non-neurological event – indirect causation
2. neuronal death (degeneration) (stroke/Parkinson’s) and neuronal dysfunction
(epilepsy/MS) (e.g. due to disease of support cells – glioma)
3. negative sign = loss of function (e.g. in stroke, loss of voluntary motor
activity), positive sign = abnormal function (e.g. in stroke, ++ pronounced
reflexes)
4. contralateral relationship (i.e. R side of brain controls L side of body)
5. increases
6. lost
7. trauma (skull fracture, spinal cord severance), cerebrovascular accident
(stroke – thromboembolism), infection (meningitis), metabolic (diabetic
neuropathy), genetic, environmental, auto-immune (MS)
8. CVA = sudden onset, neoplasia = gradual onset
9. brain ++ active, therefore ++ use of glucose. (can’t use proteins, lipids). Relies
on continual energy supply via blood stream.
10. Shifting of mid-line of the brain
11. metabolic = diabetes (neuropathy), genetic = Down’s Syndrome
12. CNS = integration and processing of sensory and motor information; higher
functions (eg. memory, emotion), PNS = sensory and motor innervation to
body, ANS = visceral function and homeostasis – involuntary actions eg.
contraction VSM
13. innervates skin and musculoskeletal system (c.f. ANS = visceral)
14. One
15. of the internal organs
16. functional unit of the nervous system
17. diabetic neuropathy, Bell’s Palsy
18. altered behaviour/mood, often no pathology, may overlap with neurological
problems
19. bundle of axons within CNS
20. nerves in PNS. (esp if guided by old nerve). In CNS, inhibitory factors present
and guidance cues absent.
21. history, examination, investigation
22. level of consciousness, speech, mental state/cognitive function, cranial nerve
function, motor function, sensory function
23. electrophysiology = EEG, EMG, NCS. Imaging = CT, MRI
24. structure and function
25. left
26. large nucleus, + + mitochondria, + + lysosomes, + + well developed Golgi,
highly organised cytoskel
27. bouton and varicosite
28. 9:1
29. Fast anterograde
30. if axon is damaged, end of severed axon seals and swells – amt of swelling can
be used to time injury
31. axon hillock – most easily depolarised
32. Nodes of Ranvier
33. microtubules
34. synaptic vesicles, mitochondria, transmitters
35. cytoskeleton components
36. fast retrograde – return of organelles, transport of substances from
extracellular space
37. pseudo-unipolar
38. dorsal root ganglion neurons
39. DRG have no dendrites (and receive no synapses). Act as a continuous cable
carrying impulses from peripheral receptor organ to central terminal in spinal
cord
40. cerebral cortex, retina
41. Type 1 = long axons, Type 2 = short axons
42. multipolar
43. glutamate and aspartate
44. muscles, glands
45. pyramidal
46. group of unencapsulated neuronal cell bodies in the CNS. Cells have similar
function
47. fibre tracts = in CNS, nerves = in PNS
48. corpus callosum
49. ganglion
50. laminae
51. co-ordinate and integrate information from sensory input and motor output
52. on dendrite = excitatory, on cell body = inhibitory, on axon terminal =
modulatory
53. astrocytes
54. fibrous = longer, thicker processes and + + Int Filament bundles; protoplasmic
= thinner, shorter processes (look fuzzy on slide)
55. yes
56. support (scaffold) for other cells, clearance of transmitters from synapses,
blood-brain barrier, respond to injury by migration and proliferation =
scarring, segregation of synapses
57. produce myelin in CNS
58. nuclei small and spherical. Prominent Golgi
59. ~ 40
60. Multiple Sclerosis
61. slows/prevents transmission of impulse down axon
62. Schwann cells
63. promote repair / axonal regeneration
64. 1:1
65. epithelial type cells – line ventricles and central canal of spinal cord
66. apical microvilli + cilia, prominent gap junctions, no tight junctions
67. phagocytes
68. resident macrophage population
69. rate of movement of molecules across a surface
70. axonal regeneration
71. outside the cell
72. negative
73. none (ie. all cells have a membrane potential)
74. membrane is selectively permeable AND concentration of at least one
permeant ion is different on 2 sides of the membrane
75. not significantly
76. when electrical gradient across membrane balances concentration gradient
77. electrical potential needed to balance the concentration gradient
78. yes
79. change in membrane potential in response to stimulation (e.g.
neurotransmitter, temperature, pressure)
80. depolarisation, hyperpolarisation
81. charge moves down axon. Spread is decremental (c.f. action potentials).
Depolarisation not sufficient to reach threshold.
82. they’re not!
83. membrane potential moves closer to the equilibrium potential for that ion
84. K+ - because the membrane is much more permeable to K+ than to Na+.
Follows that significant –ve potential needed to balance tendency of K+ to
diffuse down concentration gradient out of cell. Membrane slightly permeable
to Na+, so memb potential slightly more positive than K+ eqm potential (to
balance flow of Na+ into cell down conc gradient).
85. closed
86. depolarises it
87. Na+. Because membrane depolarisation causes +++ increase in membrane
permeability to Na+. (increase in K+ permeability much slower)
88. towards eqm potential for Na+ (ie. becomes more positive)
89. ++++ reduction in membrane permeability to Na+. Increase in membrane
permeability to K+.
90. Open. Open.
91. Period during which Na+ channels will not open in response to stimulus,
however large. Therefore no action potentials can be generated.
92. No – skeletal muscle is an example of one that doesn’t
93. K+ channels remain open, so permeability to K+ is greater than at rest. Na+
channels are shut so difference can’t be offset. Greater –ve charge inside cell
needed to oppose K+ movement out of cell.
94. Non-decremental spread. All or nothing (if stimulus is enough to get to
threshold, full ap generated regardless of size of stimulus), Refractory period
(no summing of potentials)
95. Local current flow depolarises adjacent areas (on both sides. However, action
potentials can only be generated on one side because of refractory period).
96. 1 m/s , 120 m/s
97. axon diameter, myelination, cold, anoxia, anaesthetics, other drugs
98. type of conduction in myelinated axons – aps only generated at unmyelinated
areas (Nodes of Ranvier)
99. Quicker
100.
ap doesn’t have to be regenerated in the myelinated sections – charges
from one node attract those from the next, depolarising to threshold.
101.
no – non-decremental spread
102.
graded potentials, other action potentials
103.
amino acids (eg. glutamate), amines (NA, dopamine), neuropeptides
(opioid peptides)
104.
transmit signals across a synaptic cleft between neurons
105.
enable docking of vesicles with pre-synaptic membrane in synaptic
zone via formation of complex of interlocking alpha helices
106.
alpha helices
107.
Ca2+
108.
ATP
109.
~ 10 to the -7 (very small therefore very sensitive to change)
110.
tetanus, botulinum, latrotoxin
111.
first 2 = inhibit transmitter release (via Zn 2+ dependent
endopeptidases), 3rd stimulates transmitter release to depletion
112.
ion channels. G-protein linked receptors
113.
Depends on the ion! Excitatory = depolarisation of membrane
114.
Inhibitory = hyperpolarisation of membrane
115.
fast excitatory glutamate receptors
116.
NMDA – slow glutamate receptors
117.
need another simultaneous input to cell
118.
via Excitatory Amino Acid Transporter
119.
10 to the -15
120.
epilepsy
121.
glutamine
122.
gamma amino butyric acid
123.
B6
124.
Cl125.
slow = NA, Dopamine, Ach (muscarinic), fast CNS = glutamate,
GABA, fast NMJ = Ach
126.
barbiturates, benzodiazepines
127.
glutamate has widespread effects on eg. respiratory system – to reduce
its activity systemically would be dangerous – instead focus on modulating its
activity
128.
generalised = widespread involvement of both hemispheres from the
start. Partial = focus on cerebral cortex
129.
generalised seizure with + + motor involvement (literally, ‘stiffeningjerking’
130.
glutamic acid decarboxylase. From glutamate (Vit B6 dependent)
131.
GABA transporter
132.
succinyl semi-aldehyde
133.
GABA-transaminase (GABA-T)
134.
Cranial nerves
135.
respiration, consciousness, heart rate – generally vital functions
136.
usually death, if not, coma inducing
137.
co-ordinates movement
138.
very poor co-ordination, ++ clumsiness
139.
thalamus and hypothalamus
140.
thal = relay station containing synapses between neurons from cerebral
cortex and to other areas of the brain. Hypothal = control of endocrine
function via pituitary, ANS, - homeostatic mechanisms
141.
pituitary gland, via infundibulum
142.
all
143.
primary motor cortex
144.
gyri and sulci (folds and valleys on the surface of the hemispheres)
145.
lateral fissure (separating frontal and temporal lobes), central sulcus
(separating frontal and parietal lobes)
146.
one which controls a function such that a lesion in it results in a
reproducible deficit
147.
association cortex = effect of lesion are variable between individuals
(prob involved in integration of information)
148.
Lateral ventricles (x2), 3rd ventricle, aqueduct, 4th ventricle [central
canal]
149.
3rd ventricle
150.
pons and medulla
151.
Choroid plexus in ventricles (effectively a gland)
152.
~ 150ml
153.
~ 500 ml/day
154.
reduced
155.
Mg2+ and Cl156.
Much less protein and few cells
157.
sub-arachnoid space (between arachnoid and pia mater)
158.
Small gaps in the dura mater that allow the arachnoid membrane to
protrude into the venous sinus
159.
Wernike’s area
160.
primary motor
161.
inferior, posterior occipital lobe
162.
dura mater, arachnoid and pia mater
163.
pia mater (adherent to surface of brain)
164.
veins
165.
superior sagittal
166.
protect the brain (acts as shock absorber), metabolic functions (thought
to remove some waste products)
167.
reabsorbtion of CSF into blood
168.
motor function (contain cell bodies of motor neurons)
169.
brain
170.
a vertebra and its associated spinal nerves
171.
below L2 (usually done between L3 and L4). CSF present within
vertebral column but spinal cord has finished = no risk of damaging it. In
child, spinal cord longer w.r.t. vertebral column, so do bit lower (eg. L5 and
S1)
172.
Doral root ganglia
173.
both directions (contains both sensory and motor fibres)
174.
31 pairs
175.
Cervical (nerves above respective vertebra until C7 – 7th above it, 8th
below it and then below their respective vertebra)
176.
indentations in the base of the skull
177.
middle, anterior, posterior
178.
it lies above the body of the sphenoid bone
179.
medulla
180.
intervertebral foramen
181.
abnormal increase in the amount of CSF in the ventricles
182.
communicating involves all 4 ventricles (meningitis, sub-arachnoid
haemorrhage), non-communicating doesn’t (aqueduct stenosis, ventricular
tumour)
183.
child = increased head diameter, irritability, loss of upward gaze. Adult
= headache, drowsiness, blackouts
184.
diverting fluid (shunt), removing cause (eg tumour), opening
alternative pathway (ventriculostomy)
185.
veins
186.
arteries
187.
sub-dural usually gradual onset (often in old age – why?), epi-dural
usually sudden (eg. following head injury) epidural usually fatal
188.
fever, neck stiffness, photophobia, severe headache, fits, drowsiness
(meningococcal rash often present)
189.
bacterial = neisseria meningitidis, strep pneumoniae, viral = CMV,
mumps, HIV, EBV
190.
bacterial
191.
~75%
192.
bacterial = neutrophils, NK cells, viral = lymphocytes
193.
more protein in bacterial
194.
more
195.
afferent = sensory, efferent = effector (somatic, autonomic, enteric)
196.
skeletal muscle
197.
autonomic nervous system
198.
sympathetic and parasympathetic
199.
ventral horn of the spinal cord
200.
cell bodies of sensory neurons (nb. NO SYNAPSES, cf autonomic
ganglia)
201.
Schwann cells, satellite cells
202.
sensory and autonomic ganglia
203.
neurons, glial cells, connective and vascular tissue components
204.
ventral root is anterior in location and motor in function, dorsal is
posterior and sensory
205.
distal to the dorsal root ganglia
206.
ventral rami, dorsal rami and rami communicans
207.
dorsal
208.
axons of pre-ganglionic sympathetic motor neurons and postganglionic sympathetic neurons innervating visceral structures
209.
31
210.
brachial plexus (from spinal nerves C5 – T1) and sacral plexus (L2 –
S2)
211.
dermatome
212.
its own area and half of each adjacent area
213.
decrease in sensitivity (cf anaesthesia, = total loss)
214.
plexuses (w.e.o. T2 – T12)
215.
Form network and recombine to form peripheral nerves (with
combination of nerves originating from different spinal nerves)
216.
total loss of sensation and motor function in the area supplied by the
nerve
217.
ulnar
218.
wasting of hand muscles and loss of sensation over little finger
219.
medial
220.
badly placed injections
221.
fascicles
222.
whole nerve, loose connective tissue
223.
perineurium, dense connective tissue
224.
epineurium
225.
yes
226.
recording of action potential from nerve showing several peaks,
representing conduction along axons with different conduction velocities
227.
~ 100
228.
salutatory / continuous
229.
yes
230.
break down and are phagocytosed by macrophages
231.
48 hours
232.
Wallerian degeneration
233.
metabolic changes undergone in cell bodies of damaged neurons
234.
make contact with Schwann cell and find their endoneurial sheaths
235.
neuroma – collection of trapped axons
236.
2 – 5 mm/day
237.
axonal degeneration or demyelination
238.
nerve biopsy
239.
Charcot-Marie-Tooth disease
240.
electromyography (measures action potentials in muscle fibres) – in
response to stimulus of peripheral nerve.
241.
hypothermia, demyelination, increased pressure on nerve
242.
adductor pollicis
243.
CMT disease
244.
MS
245.
Carpal Tunnel Syndrome
246.
White, myelin
247.
blockage in nerve
248.
strong collagenous fibres
249.
perineurium
250.
epineurium
251.
parasympathetic and sympathetic
252.
symp = vascular tone, ejaculation, pupil dilation, increased CO
parasymp = erection, bladder control, pupil contraction, vagal tone to heart
253.
parasymp = cervical and sacral regions, symp = thoracic and lumbar
254.
pre-ganglionic are longer
255.
post-ganglionic are longer (pre-ganglionic tend to be short as synapse
in the sympathetic chain)
256.
a modified post-ganglionic fibre
257.
secreted directly into blood-stream not across a synapse
258.
mass activation of symp nervous system
259.
sympathetic
260.
inotropic = force of contraction, chronotropic = heart rate
261.
sympathetic
262.
when stimulated, causes vasoconstriction, increasing TPR. MABP
increases to maintain CO
263.
arterioles
264.
blood vessels supplying skeletal muscle (need inc blood supply in fight
or flight)
265.
NO, CO2, histamine,
266.
in the brain – maintenance of cerebral blood flow
267.
parasympathetic stimulation
268.
symp = decreased motility and tone, contraction of sphincters,
reduced/inhibited secretory activity, parasymp = increased motility and tone,
relaxation of sphincters, stimulation of secretory activity
269.
contraction cilliary muscles causes lens to bulge for near vision =
parasymp
270.
radial
271.
papillary sphincter
272.
parasymp
273.
pelvic
274.
pudenal
275.
pelvic
276.
no – erection = parasymp. Ejaculation = symp
277.
k
278.
Adrenaline has an extra methyl group
279.
choline ester
280.
Ach
281.
Symp = Usually catecholamines (NA/A). W.e.o. sweat glands = Ach.
Parasymp = Ach
282.
ligand gated ion channels
283.
Adrenoreceptors (a1, a2, b1, b2, b3)
284.
Sweat glands – cholinergic post ganglionic fibres
285.
when designing drugs. (What 2 ways could this cause problems?)
286.
Nicotinic
287.
80%
288.
Acetyl choline esterase
289.
Synaptic cleft
290.
Choline and acetate
291.
Acetyl CoA and Choline
292.
Tyrosine
293.
DOPA
294.
dopa decarboxylase
295.
vesicles
296.
dopamine beta hydroxylase
297.
by the action of phenylethanolaminemethyl transferase (cytoplasmic
enzyme that methylates it)
298.
in the cytoplasm
299.
vanillyl mandelic acid and MOPEG (3-methyl, 4-hydroxy
phenylethelene glycol)
300.
levels of them in urine can indicate level of symp NS activity
301.
catechol-O-methyl transferase, monoamine oxidase A
302.
COMT
303.
catecholamine producing cells of the adrenal medulla
304.
methylation of NA to form A
305.
autonomic failure
306.
respond to stretch – their basal activity is an inhibition of symp tone
307.
Carotid sinus and aortic arch
308.
Carotid sinus
309.
parasymp
310.
both eyes will constrict in response to light shone in one eye
311.
optic nerve
312.
occulomotor
313.
j
314.
tilt test
315.
blood is diverted to the digestive system, therefore less blood available
for rest of body, specifically the brain (and also tend to sit down when eating
and drinking)
316.
Fainting
317.
10%
318.
Pacemaker; to prevent cardiac arrest following very low heart rate
because of overactive vagus
319.
needle phobia
320.
vasovagal attack