Week 1 Neuro Flashcards
(203 cards)
2
Q
Describe the information flow in neurons:
A
Information is received form the dendrites
Processed (summed) at the axon hillock
If triggered the action potential travels down to axon to the synaptic cleft
3
Q
Transmitters released from the nerve terminal activates what? This causes what?
A
Transmitters released from the nerve terminal activates post-synaptic receptors and causes an influx of ions or activation of second messengers
4
Q
In the cycle of transmission of a neurotransmitter describe the step from synthesis to just before release
A
Synthesis in cell body, anterograde transportation to nerve ending, uptake into synaptic vesicles, storage in synaptic vesicles, release to synaptic cleft
5
Q
In the cycle of transmission of a neurotransmitter describe the step from release to degradation
A
Released to synaptic cleft, then binding to and activation of post-synaptic receptors
Then the neurotransmitter can then be processed in one of three ways
1. Extracellular enzyme destruction
2. Reuptake directly into the terminal
3. Reuptake into the cellular compartment then converted to an inactive metabolite and reused as needed;
6
Q
what is the extremely simplified cycle of neurotransmission?
A
Release => Action (receptor binding) => Disposal (re-uptake)
7
Q
What are the three main types of neurotransmitters?
A
Excitatory (+ firing likelihood)
Inhibitory (- firing likelihood)
Neuromodulators
8
Q
The likelihood of action potential is determined by?
Where is this determination made?
A
The likelihood of an action potential is determined by the summation of all inputs
this occures at the Axon Hillock
9
Q
What are the two most widely used amino acid transmitters in the CNS?
Generally what is there function?
A
Glutamate (excitatory)
GABA (inhibitory)
10
Q
GABA and Glutamate can be what?
A
Interconverted by a single enzymic step
11
Q
Both GABA and Glutamate are derived from what cycle? What molecule can they be converted from?
A
The TCA cycle;
Alpha-Ketoglutarate => Glutamate => GABA => Succinate
12
Q
Glutamate is involved in what? (2 things)
A
Learning and memory
Many neuro-psychiatric diseases
13
Q
GABA-alpha receptor is the site of action of what kind of drugs?
Give some examples
A
GABA-alpha receptor is the site of action of many psychoactive drugs
including: alcohol, barbiturates, tranquilizers (benzos)
14
Q
In excitotoxicity there is an imbalance between?
It is implicated in? (3 Things)
A
There is an imbalance between excitatory and inhibitory signals
Epilepsy, Alcohol-induced brain damage and Alzheimer’s
15
Q
What is the most common Neurotransmitter in the peripheral nerves?
A
Acetylcholine (Ach)
16
Q
Acetylcholine is synthesised from what?
This process requires what and utilises what enzyme?
A
Choline
The process requires ATP and the enzyme that is used is choline acetyltransferase
17
Q
what are the two main Catecholamine neurotransmitters?
A
Dopamine; noradrenaline
18
Q
Catecholamine’s are derivatives of what neurotransmitter?
A
Tyrosine
19
Q
Dopamine receptors can do what to cAMP? What are the receptor types for each?
A
both increase or decrease cAMP; D1 like receptors (D1 and D5) increase while D2 like (D2; D3 and D4) decrease
20
Q
antipsychotics are D2 what? Antiparkinsonian are D2 what
A
antipsychotics are D2 antagonists; Antiparkinsonian drugs are D2 agonists;
21
Q
cocaine and amphetamines block what?
A
Dopamine transporter
22
Q
Peptide transmitters precursors are synthesised in the what? What happens to them post releases?
A
Peptide transmitter are synthesised in the Golgi apparatus; post realise they are degraded in the synaptic cleft they are not reused
23
Q
Fast Release transmitters are storied where? What are their actions post depolarisations?
A
Attached to an asctin web in the terminal; when an action potential arrives at the terminal it causes an influx of Ca+2; docked vesicles then fuse with the membrane releasing there neurotransmitters into the cleft; empty vesicles are then recycled and refiled; the actin web breaks down and new vesicles move to dock
24
Q
Slow release neurotransmitters are located where? What are their actions post depolarisations?
A
Slow release transmitters are not located on the cell membrane; Trains of action potentials are required o mover them to the membrane before contents can be released
25
Q
Describe kiss and run; what transmitters utilise this system?
A
Synaptic vesicles merge with the cell membrane but do not fully discharge their contents into the cleft; the vesicle then is re-filled with the neurotransmitters that where lost; slow release
26
what are the two common receptor actions?
Ion fluxes; second-messenger cascades
27
contrast hormone receptors and neurotransmitter receptors
Hormones are slow release they affect receptors at long range and they have very high affinity for the hormone; Neurotransmitters are fast released they affect receptors at a very short range and they have lower affinity for the neurotransmitter
28
most G-coupled receptors are composed of how may proteins; how many transmembrane domains?
single proteins with 7 transmembrane domains; multi-protein complexes each subunit has 4 transmembrane domains
29
most ion gated channel receptors are composed of how may proteins; how many transmembrane domains?
multi-protein complexes in which each subunit has 4 transmembrane domains
30
in the resting state an ion channel is what?
Closed
31
When activated the ion channel receptor undergoes what? This allows?
A conformation change; allows ions to flow into the cell
32
what do cations and anions do to the cell? Give example of both
Cations (K / Na/ Ca) depolarize the cell; Anions (Cl) hyperpolarize
33
at the Neuromuscular junction what receptor is activated?
Nicotinic acetylcholine receptor
34
at the Neuromuscular junction What neurotransmitter is used? what degrades this neurotransmitter?
Acetylcholine; acetylcholinesterase;
35
On a Ligand-Gated Ion Channel there are how many binding sites? These can bind?
multiple binding sites; can bind agonists or modulators
36
describe the mechanism of activating a g-protein linked receptor
agonis activation -\> conformation change -\> alter second-messenger -\> turn over in the cell
37
there are _______ receptors for each neurotransmitter?
Multiple
38
neurotransmitter transporters are all Coupled with? Glutamate's transporter is also coupled with?
GABA glycine dopamine noradrenaline and serotonin transports are also coupled with?
39
Neurotransmitter transporters are driven by?
ionic gradients
40
The divisions of the nervous system are ?
CNS and PNS
41
what makes up the CNS
Brain and spinal cord
42
what makes up the PNS
Cranial nerves; spinal nerves; peripheral nerves
43
what two systems make up the peripheral nervous system
Somatic Nervous system (Sensory and motor neurons) and the Autonomic nervous system (Sympathetic and parasympathetic)
44
generally speaking the soma or body wall consists of derivatives of the?
mesoderm
45
generally speaking the viscera or organs consists of derivatives of the?
endoderm
46
generally speaking the Nervous System consists of derivatives of the?
ectoderm
47
the neural tube develops into the?
Spinal cord
48
what are the two special sensory visceral systems?
taste and smell
49
what are the five major special senses
Taste; smell; hearing; equilibrium; vision
50
why is there an enlargement at the C5 - T1 level?
there is a lot of grey matter due to large number of cell bodies that deal with the motor and sensory inputs from the upper limbs; also there is a lot of white matter that represents all the information from the lower part of the body
51
as we go up the spinal cord the amount of white matter?
increases
52
what are the vertebral foramen? What do they make up?
the vertebral foramen is the opening formed by the anterior segment and the posterior part of the vertebral arch; this creates the channel that the spinal cord sits in
53
what are the three layers of the meninges?
Dura mater; arachnoid; pia mater
54
in the spinal cord the gray mater is shaped like?
a H
55
the dorsal root ganglion contains what type of neurons?
sensory
56
what is a ganglion
a collection of neuronal cell bodies outside the CNS
57
the anterior root contains what type of fibbers?
Motor
58
whare are the cell bodies of peripheral motor neurons?
Gray mater of the spinal cord
59
what are the two types of rami form a spinal nerve?
Posterior and anterior rami
60
the brachial plexus consists of nerves from what levels?
C5 to T1
61
how many cervical nerves are there? How many cervical Vertebra Why
8 cervical nerves but only 7 cervical vertebrae; because the convention on how to name the nerves flips at the c7 level to naming the nerve at the level below which it exits
62
what are the components that make up the brachial plexus?
5 Roots; 3 trunks;6 divisions; 3 cords;
63
what roots make up the superior trunk
C5 and C6
64
what roots make up the middle trunk
C7
65
what roots make up the inferior trunk
C8 and T1
66
the lateral cord gives rise to what two major nerves of the lower limb?
Musculocutaneous and the median
67
the posterior cord gives rise to what two major nerves of the lower limb?
axillary and radial
68
the medial cord gives rise to what two major nerves of the lower limb?
ulnar and median
69
what are the five major nerves of the upper limb? What are they Vertebra levels supply them?
Axillary (C5 and C6); Radial nerve (C5-T1 All levels); Musculocutaneous nerve (C5-C7); Median Nerve (C5-T1 all levels); Ulnar nerve (C7-T1)
70
what muscles does the Axillary nerve supply?
Deltoid and teres minor
71
what muscles does the radial nerve supply?
Posterior arm muscles and the posterolateral muscles of the forearm
72
radial nerve paralysis major presenting issues is?
Wrist Drop
73
What muscles does the musculocutaneous nerve supply?
supplies the anterior arm muscles that produce flexion at the elbow
74
in the upper limb what nerve the anterior compartment muscles are supplied by what nerve? The posterior compartment muscles are supplied by what nerve? The lateral compartment muscles are supplied by what nerve
Anterior: Musculocutaneous; Posterior: Radial; Lateral: Axillary
75
what muscles does the median nerve supply?
anteromedial muscles of the forearm and the muscles of the thenar eminence
76
what structures go though the carpal tunnel?
four tendons from the flexor digitorum profundus; four tendons of the flexor digitorum superficialis; and one tendon of the flexor pollicis longus; and the median nerve
77
median nerve injury can be caused by trauma in what area?
cubital fossa or at the wrist (compression passing through the pronator teres or compression in the carpal tunnel)
78
that is the major presenting issue with a median nerve injury?
Thenar atrophy; loss of opposition; clawing of the digits II And III
79
flexion and abduction of the thumb is still possible after a median nerve injury due to what muscles?
Flexor pollicis longus and abductor pollicis longus
80
what muscles does the ulnar nerve supply?
Flexor carpi ulnaris and the medial half of flexor digitorum profundus; and all the intrinsic muscles of the hand (Except those of the thenar eminence)
81
the nerve of fine motor control of the hand is what nerve?
Ulnar nerve
82
describe the five factors in nervous communication
Sensor (Receptor/transducer for a specific stimulus); Stimulus (exceeds minimum threshold/energy); Conduction (Fast transmission of electrically isolated signal); Processing (interneurons enhance modify and relate signals); Contextual perception (signal reaches consciousness is moderated by context)
83
what are the function units of communication in the nervous system?
Neurones
84
Neurons at rest:
Have negative resting membrane potential; receive inputs which summate to change membrane potential transiently
85
Neurons in action:
Have sufficient summated input to change membrane potential to more positive threshold levels; this triggers OUTPUT (the action potential)
86
how to ions move across neuron membranes? Is it Active or passive?
Specific Transporter proteins (both active and passive; move ions Against their gradients); Ion channel proteins (always passive; allow ions to move with gradients
87
Resting membrane potential is due to what enzyme? It is largely determined by what ion?
Na+-K+ ATPase pump; K+
88
inputs to the neurons summate making it?
Inputs to neurons summate; making it MORE or LESS likely to produce an ACTION POTENTIAL
89
Excitatory synaptic potentials ________ the resting membrane potential pushing the neuron ________ to the threshold
Excitatory synaptic potentials depolarize the resting membrane potential pushing the neuron closer to the threshold
90
Inhibitory synaptic potentials ________ the resting membrane potential pushing the neuron ________ to the threshold
Inhibitory synaptic potentials hyperpolarize the resting membrane potential pushing the neuron away from the threshold
91
Depolarizing the resting membrane potential occurs by?
Opening ion channels permeable to ions with Nernst potential +ve to Em
92
Hyperpolarizing the resting membrane potential occurs by?
Opening ion channels permeable to ions with Nernst potential ?ve to Em
93
ion channels can be opened by?
Membrane potential or direct electrical stimulation; Neurotransmitters; Mechanical/chemical forces
94
What is the order of channels that open in an action positional?
once the threshold has been reached; voltage-sensitive Na+ ion channels rapidly open this leads to a strongly depolarizing the resting membrane positional; This channels automatically close; then the voltage-sensitive K+ channels slowly open strongly Hyperpolarizing the resting membrane positional
95
describe the flow of an action potential
AP normally travel from soma to synaptic terminals at the end of the axon; this triggers the synaptic release of neurotransmitters which generate PSPs in target neurons or tissues
96
what does the conduction velocity of an AP depend on?
Dependent on axon diameter and degree of myelination
97
regular breaks in myelin allow what kind of conduction? What are these breaks called?
Saltatory Conduction of nerve impulse from node to node; Node of Ranvier
98
myelin insulation allows?
Rapid passive spread of current within axon cytoplasm rather than leaking across axon membrane
99
describe what happens to an AP as it spreads from a Node of Ranvier
Ap depolarization generated at single node spreads passively to adjacent membrane and decreases with distance from node
100
Rate of spread depends on?
Rate of spread depends on axon diameter
101
Voltage gated Na+ channels are concentrated where?
At the Axon Hillock
102
how does the international association for the study of pain define pain?
an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage
103
how did Margo (No Suggestions) describe pain?
Pain is whatever the experiencing person says it is existing whenever s/he says it does
104
Describe Acute Pain
useful protective warning of external/internal environmental change which can harm body leading to adaptive avoidance behaviour
105
Describe Chronic Pain
Maladaptive signal which can lead to long-term withdrawal and environmental indifference
106
what are the four steps in sensing pain
Transduction (painful tissue stimuli transduced into electrical neural activity by peripheral nociceptors); Transmission (nociceptor afferents transmit pain signals to spinal cord and brain); Perception (pain perception involves central processing of nociceptor signals in spinal cord/brainstem/thalamus and cortex); Modulation (descending inhibitory and facilitator input from higher brain centres influences nociceptive transmission in spinal cord)
107
what do Nociceptors respond to?
Nociceptors response to stimuli which damage tissue or could potentially damage tissue; this may be due to a direct response from a stimuli or factors released by the stimuli
108
Where do nociceptors synapses? Where is the cell body
Axon synapses in the dorsal horn of the spinal cord or brainstem sensory nuclei; Cell body is in the Dorsal root or cranial nerve ganglia
109
what are the four types of nociceptors? What do they respond to?
Noxious Mechanoreceptors: Respond only with strong mechanical stimulation and most effectively with sharp objects; Heat Nociceptors: Respond only when temp \> 45 deg C; Polymodal nociceptors: respond equally to all mechanical temperature and chemical noxious stimuli; "Sleeping" nociceptors: Normally unresponsive unless tissue is inflamed or injured then show Polymodal responses
110
Activation of nociceptive transducer receptor/ion channel complexes causes?
Generator potential: graded membrane depolarization with increasing intensity of noxious stimuli
111
Nociceptor afferent firing rate is lower or higher than non-nociceptor sensory afferent firing rate?
Lower
112
Many nociceptors show what kind of firing rate with prolonged noxious stimulus? This is know as?
Many nociceptors show slowing firing rate with prolonged noxious stimulus; know as adaptation
113
Aps are due what ion channel in Nociceptors?
NA+
114
spinal cord and cranial sensory nuclei exhibit layering these are know as what?
Laminae in the gray mater
115
how do Nociceptors and somatosensory project into the grey matter?
Nociceptors and somatosensory receptors project into different Laminae
116
where do fast pain nociceptors project to? What neurotransmitter do they use? What type of fibres are these?
Project into the Laminae I and they release Glutamate; these fibres are Alpha-alpha or type III fibres
117
where do slow pain nociceptors project to? What neurotransmitter do they use? What type of fibres are these?
Project into the Laminae II and III and they release Glutamate and Substance p; these fibres are C fibres or type IV
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where do somatosensory receptors project to?
Project into the Laminae III and IV
119
Describe the general flow of information once a painful stimulus is presented
Nociceptors in the affected area triggers the spinothalamic tract -\>brainstem-\>midbrain-\> Thalamus -\> Limbic system and Cingulate cortex and Somatosensory cortex
120
The descending pathways from the periaqueductal gray can?
Descending pathways from the periaqueductal gray and brainstem can inhibit spinal projection neurons receiving pain signals (Modulating the pain)
121
what neurotransmitter do the descending pain pathways utilise to modulate pain? What type neuron is used? What other substance utilises this system?
Interneurons release enkephalin which reduces or blocks synaptic neurotransmitter release evoked by pain; Exogenous opiates
122
Rank the nerve fibres in terms of Conduction velocity and Axon Diameter: are they the same and why?
Alpha-alpha \> Alpha-Beta \> Alpha-Gamma \> Alpha-Delta \> Beta \> C; same with axon diameter because speed is directly related to diameter
123
Damage at the Dendrite or synapses usually causes?
Loss of dendrites or synapses can usually be resorted by regrowth/plasticity
124
Damage at the cell body usually causes?
Cell death and due to the fact that mature neurons are post-mitotic it is no replaced
125
Damage to an Axon or target innervation causes?
In the CNS axon regrowth is inhibited/limited by the environment; in the PNS axonal regrowth is possible but it needs support/guidance cues
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How does Axonal injury elicit a regenerative response I the neuron soma?
Loss of normal retrograde neurotropic signals; Retrograde axonal transport of positive (growth) signals from nerve stump
127
in Wallerian degeneration what is the distal and proximal end? What happens to the distal end? What happens to the proximal end?
the distal end is the end that has been severed from the cell body it degrades all the way to the site of innervation; the proximal end is the side with the cell body and it degrades to the next node of ranvea
128
in Wallerian degeneration what three things happen to re-establish normal neuronal function?
Regeneration of the proximal axon involves; Axon guidance path and molecular cues; re-myelination by the glial cells; re-innervation of target tissue
129
In axonal transport what supports the movement? Synthesis and assembly of molecules occurs in the? What molecules are responsible for the movement and in what direction?
Microtubules; Synthesis and assembly take place in the soma of the neuron; Anterograde (toward the nerve terminal) is accomplished by Kinesins; Retrograde transport (toward the nerve cell body) is accomplished by dynein
130
in general what is transported anterograde?
Transmitters and Structural proteins
131
in general what is transported retrograde?
Debris viruses; and growth factors
132
in Axonal guidance what it the first area called; what does it do?
The growth cone; establishes a pathway and detects physical cues to continue to grow or degrade
133
in terms of guidance signals; what are three broad types and some examples of each?
Adhesive substrate-bound cues (the roadway) CAMs and ECM; Repellent substrate-bound cues (the roadways guard rails) Slits and ephrins Chondroitin sulphate proteoglycans; Diffusible chemotropic cues (Road signs) class guidance molecules (netrins and semphorins) neurotransmitters growth factors
134
A nerve is usually made up from a variety of fascicles what are the layers around these fascicles?
Epineurium (surrounds the many fascicles that make up the anatomical nerve); perineurium (surrounding individual fascicles); endoneurium (surrounds the nerve fibbers them selves)
135
even if an axon is damaged the conduit made up of What and what will often survive and provide a pathway for regrowing axons?
even if an axon is damaged the conduit made up of Perineurium and epineurium will often survive and provide a pathway for regrowing axons?
136
what can trigger wallerian degeneration in the PNS?
Triggered by severe nerve injury (trauma; transection; toxins; inflammation and demyelination; neurodegeneration) or blockade of axonal transport
137
in Wallerian degeneration describe what happens in the neuron soma and proximal axon.
there is an aggregation of protein in the soma; trophic factors prevent proximal axon loss; macrophages invade injury and secrete cytokines and secretion of extracellular proteins by Schwann cells cause a proximal axon to sprout within around 96 hours
138
in wallerian degeneration describe what happens in the distal axon.
Degeneration over a 1-2 weeks; Glial cells push synaptic terminals away from the muscle; the myelin sheath degrades; Schwann cells begin to remove debris; but the Schwann cells and endoneural tube persists as support/guides for 1-2 months
139
what is the main tool in determining peripheral nerve damage/demyelination
Electrophysiology
140
what is the prognosis of a injury that leaves the axon and nerve structure intact but creates a nerve conduction block in the PNS?
Prognosis is very good; 3-4 month recovery
141
what is the prognosis of a injury that leaves axonal damage but the nerve structure is intact in the PNS?
prognosis is good; axon regrowth at ~1 mm/day from injury to tissue target
142
what is the prognosis of an injury that has axonal and nerve structure damage in the PNS?
variable; needs surgical nerve reconnection followed by axonal regrowth; up to 18 mths
143
what does surgical approximation of a peripheral nerve aim to do?
Realign the nerve fascicles for axon guidance
144
what are four aids to peripheral nerve repair?
Fibrin tissue glue; nerve conduits; electrical stimulation; nerve graft
145
how does fibrin tissue glue help with peripheral nerve repair
provides extracellular matrix around the nerve approximation; prevents invasion of scar tissue
146
what are the two types of nerve graft
isograft uses sensory nerves from the same patient; allograft uses processed nerve from donor
147
how do nerve conduits help peripheral nerve repair?
They provide a guidance path for axonal growth; prevent scar tissue invasion and axon escape; creates a nerve growth factor rich local environment;
148
CNS axons have the capacity to regenerate but?
the environment inhibits this
149
what are two factors that inhibit axon growth in the CNS?
glial cells secrete inhibitory factors; formation of glial scar block axonal growth;
150
what are three stem cell sources?
Pluripotent stem cells from embryonic tissue; induced transformation of tissue stem cells; the adult brain has a small number of stem cells
151
where are pluripotent stem cells derived from?
blastocyst or embryonic tissue
152
where do induced pluripotent stem cells come from?
Genetic reprogramming of adult cells (skin)
153
what are some benefits to induced pluripotent stem cells?
Avoids rejection problems; less ethical concerns
154
what are some issue with using adult neural stem cells?
there are few present; identification and harvesting is very difficult; they may have some significant DNA errors
155
describe neural interface systems
Brain activity can be used to directly control muscle; computers or other assistive or prosthetic devices
156
the upper limb is an organ of?
Manipulation
157
what determines the position of the scapula? Name them?
Muscles; Trapezius; Serratus Anterior; Pectorals; Latissimus Dorsi; Rhomboids
158
what can causes winging of the scapula
weakness or paralysis of the Serratus anterior
159
what is a postural muscle
a muscle that is active to maintain normal posture
160
what are the two postural muscles of the shoulder?
Trapezius; Supraspinatus
161
how many heads do the pectorals major have? What are they?
two; Clavicular and the sternocostal
162
what are the rotator cuff muscles? What is there major purpose?
infraspinatus; Teres minor; Subscapularis; Supraspinatus; they act as dynamic ligaments to stabilise the glenohumeral joint; during manipulative tasks the rotator cuff muscles act as fixators of the shoulder
163
the strength of a muscles is determined by what two things?
the size of the muscle and the leverage it has
164
at a very basic level what are the three functions of muscles?
Produce torque; movement and stability
165
at a very basic level what are the two groups of muscles in the forearm?
The anteromedial group and the posterolateral group
166
what are the functions of musculotendinous units?
Musculotendinous units act: concentrically to produce movement; isometrically to stabilise joints; eccentrically to control movements
167
Musculotendinous units also provide what?
sensory feedback about muscle length and tendon forces
168
what are some broad roles of muscles?
Agonist; Antagonist; Synergists; Stabilisers; Fixators
169
what do agonists muscles do? What are the subtypes to this group?
muscles that produce the movement; Prime mover (main member of this group; Assistant movers (other members of this group)
170
What do antagonists muscles do?
Muscles that oppose the movement;
171
what do true synergists muscles do?
act to prevent the unwanted actions of the agonists muscles
172
what do co-synergists muscles do?
Help each other in one direction but oppose each other in another direction
173
what do Stabilisers muscles do?
Stabiles a joint; rather than produce movement
174
what do fixator muscles do?
Stabilise proximal joints to provide a stable base for contraction of more distal muscles
175
in the hand what is the refinance point?
the third digit
176
in the opposition of the thumb what are the three motions of the thumb?
abduction; Rotation; Flexion
177
what are the superficial muscles that connect the axial skeleton and the pectoral girdle? What is there innervation? What CNS level is it at?
trapezius: spinal accessory(CN XI); sternocleidomastoid: spinal accessory (CN XI) & ventral rami: C2 C3 C4
178
what are the posterior muscles that connect the axial skeleton and the pectoral girdle? What is there innervation? What CNS level(s) are they at?
rhomboideus major: dorsal scapular:C4 C5 ; rhomboideus minor: dorsal scapular:C4 C5; levator scapulae: ventral rami dorsal scapular:C3 C4 C5
179
what are the Anterolateral muscles that connect the axial skeleton and the pectoral girdle? What is there innervation? What CNS level(s) are they at?
pectoralis minor: lateral & medial pectoral: C(5) C6 C7 C8 T1; subclavius: nerve to subclavius: C5 C6; serratus anterior: long thoracic: C5 C6 C7
180
what are the muscles connecting the axial skeleton and the humerus? What is there innervation? What CNS level(s) are they at?
pectoralis major (sternocostal head): lateral & medial pectoral: C(6) C7 C8 T1: Latissimus Dorsi: thoracodorsal: C6 C7 C8
181
what are the muscles connecting the Pectoral Girdle and the humerus (non-rotator cuff)? What is there innervation? What CNS level(s) are they at?
pectoralis major (Clavicular head): lateral & medial pectoral: C5 C6 C(7); deltoideus: axillary: C5 C6; teres major: lower subscapular: C(5) C6 C7; coracobrachialis: musculocutaneous C(5) C6 C7
182
what are the muscles connecting the Pectoral Girdle and the humerus (rotator cuff)? What is there innervation? What CNS level(s) are they at?
supraspinatus: suprascapular: C(4) C5 C6 infraspinatus: suprascapular: C(4) C5 C6 teres minor: axillary: C(4) C5 C6 Subscapularis: subscapular: C(5) C6 C7
183
what are the major muscles of the arm? What is there innervation? What CNS level(s) are they at?
biceps brachii: musculocutaneous: C5 C6 brachialis: musculocutaneous: C5 C6 triceps brachii: radial: C6 C7 C8
184
what are the major Anteromedial Superficial muscles of the Forearm What is there innervation? What CNS level(s) are they at?
pronator teres: median: C6 C7 flexor carpi radialis: median: C6 C7 Palmaris longus: median: C6 C7 C8 flexor carpi ulnaris: ulnar: C7 C8 T1
185
what are the major Anteromedial Deep muscles of the Forearm What is there innervation? What CNS level(s) are they at?
pronator quadratus: median: C7 C8 T1
186
what are the major Anteromedial Extrinsic Muscles of Hand (Intermediate & Deep)? What is there innervation? What CNS level(s) are they at?
flexor digitorum superficialis: median: C7 C8 T1; flexor digitorum profundus: median (lat) ulnar (med): C(7) C8 T1; flexor pollicis longus: median: C7 C8 T1
187
what are the major Posterolateral superficial muscles of the forearm? What is there innervation? What CNS level(s) are they at?
brachioradialis: radial: C5 C6 C7 C(8); extensor carpi radialis longus: radial: C6 C7; extensor carpi radialis brevis: radial: C6 C7 C8; extensor carpi ulnaris: radial: C(6) C7 C8; anconeus: radial: C(6) C7 C8 T1;
188
what are the major Posterolateral Deep muscles of the forearm? What is there innervation? What CNS level(s) are they at?
supinator: radial: C(5) C6 C7 C(8)
189
what are the major Posterolateral Extrinsic muscles of the hand (superficial) ? What is there innervation? What CNS level(s) are they at?
extensor digitorum: radial: C7 C8 T1; extensor digiti minimi: radial: C(6) C7 C8
190
what are the major Posterolateral Extrinsic muscles of the hand (Deep) ? What is there innervation? What CNS level(s) are they at?
abductor pollicis longus: radial: C6 C7 C8; extensor pollicis longus: radial: C(6) C7 C8; extensor pollicis brevis: radial: C(6) C7 C8; extensor indicis: radial: C(6) C7 C8;
191
what is the primary presenting compliant in a Median Nerve Injury?
Sensory loss on the lateral portion of the palmar surface of the hand.
192
A rigger falls from a platform and catches himself by his right hand on a beam. The traction ruptures T1 nerve root. What disability will result?
T1 is distributed to the intrinsic muscles of the hand; through the ulnar nerve. Sensory supply to the skin through T1 to the medial aspect of the arm and forearm will be affected.
193
A drunk sleeps with his arm over a park bench and compresses his radial nerve on the posterior aspect of his humerus. What will be his symptoms on awakening?
This can be deduced from the knowledge that the radial nerve supplies the triceps; brachioradialis; supinatorand extensor muscles of the digits. It supplies sensation to the posterior arm and forearm; plus the lateral two thirds of the dorsum of the hand
194
Identify the structures normally visible and palpable at the wrist.
On the flexor surface; flexor carpi radialis; palmaris longus; flexor digitorum superficialis and flexor carpi ulnaris are conspicuous cords. The relations of these landmarks to the arteries and nerves should be identified. On the lateral surface; the abductor pollicis longus; extensor pollicis brevis and extensor pollicis longus are seen.
195
Describe the different types of nerve fibres
Group A fibres include the largest myelinated somatic afferent and efferent fibres and have the highest conduction velocity.Group B fibres are myelinated pre-ganglionic fibresGroup C fibres are thin; non-myelinated; visceral and somatic pain fibres
196
Define the terms neurapraxia; neurotmesis and axonotmesis; and describe how they arise.
Neurapraxia is failure of conduction of a nerve in the absence of structural damage resulting in numbness; tingling and weakness. It is usually caused by compression of the nerve.Neurotmesis is the complete severance of a peripheral nerve and is associated with degeneration of the nerve fibre distal to the point of severance and slow nerve regeneration.Axonotmesis is the rupture of nerve fibres (axons) within an intact nerve sheath as a result of prolonged pressure or crushing. It is followed by degeneration of the nerve beyond the point of rupture but the prognosis for nerve regeneration is good.
197
What principles underlie the rehabilitation by physiotherapists and occupational therapists of a patient with a nerve palsy which may recover in time?
The central principle is to maintain mobility: if the limb is neglected while waiting for regeneration; the stiffness of joints due to capsule tightening may become so severe that mobility cannot be restored later; even though the nerve has regenerated. OTs are skilled in application of splintage and other aids; which prevent contractures and maximise function; as well as reorganising the environment and possibly the patient?s work around their disability.
198
What is the physiological function of the myotatic reflex?
Programmed movements; where the gamma efferent system sets muscle shortening velocity; holding a position; where the gamma system sets muscle length; contracting when load increases to prevent sagging under the load; setting muscle tone. Testing by doctors does not really qualify
199
What is the nerve supply of muscle spindles?
Afferents from the mechanotransducer region at the centre of the fibres are large class I axons; with cell bodies in the dorsal root ganglia; central processes synapsing with the alpha motor neurones supplying extrafusal muscle fibres; efferents to the contractile elements of the spindle fibres are gamma motor fibres.
200
Which of the following characterises C type nerve fibres?a) Axons lying free in the interstitial space.b) Axons lying on the surface of Schwann cells in the interstitial space.c) Axons lying within grooves on the Schwann cells.d) Axons with only a single layer of formed myelin from Schwann cells.e) Axons with fewer than three layers of formed myelin from Schwann cells.
c) Axons lying within grooves on the Schwann cells.
201
Which of the following cells are essentially the immune cells of the central nervous system and those that react most to inflammation?a) Fibrous astrocytesb) Oligodendrogliac) Protoplasmic astrocytesd) Microgliae) Schwann cells
d) Microglia
202
Which of the following statements is correct regarding the rising phase of an action potential in a neuron?a) The membrane potential becomes more negative during this phase.b) There is an influx of Na? through the nongated ion channels.c) Na? flows into the neuron through voltage-gated Na? channels.d) K? flows into the neuron through the voltage-gated K?channels.e) Energy for influx of Na?is provided by the Na? K? pump.
c) Na? flows into the neuron through voltage-gated Na? channels
203
A trauma surgeon is repairing an open fracture of the humerus. While reducing the humeral fracture; she notes that the large nerve running within a groove around the humerus has been torn. What deficit is the patient expected to have?a) Inability to extend fingers with posterior forearm anaesthesia.b) Inability to flex fingers with anteromedial forearm anaesthesia.c) Ulnar claw with intrinsic hand weakness; dorsal hand anaesthesia.d) Inability to adduct thumb with palmar anaesthesia.e) Inability to flex elbow with lateral forearm anesthesia.
a) Inability to extend fingers with posterior forearm anaesthesia.
204
A 60 year old man describes chronic weakness in abducting the left shoulder and left shoulder numbness. He does not have shoulder or back pain. The left deltoid appears wasted on examination; and sensation to pinprick of the left shoulder is decreased. He thinks that these problems began after he dislocated his shoulder four years ago. What is the most like cause?a) Left C6 radiculopathyb) Left C4 radiculopathyc) Left axillary nerve injuryd) Left musculocutaneous nerve injurye) Left radial nerve injury
c) Left axillary nerve injury
