JP lectures Flashcards
1
Q
What do dendrites do?
A
Receive info and convey signals to soma (increases cell surface area)
2
Q
Which part is the metabolic part of a neuron?
A
Soma (perikaryon)
3
Q
Where is the site of initiation of the AP?
A
Axon hillock & initial segment
4
Q
How do glia cells affect APs?
A
Insulate axons to allow signals to travel further
5
Q
What is saltatory conduction?
A
When AP ‘jumps’ from oneNode of Ranvier to the next
6
Q
What is the most frequent excitatory transmitter in the CNS?
A
Glutamate
7
Q
What are the 2 most frequent inhibitory transmitters in the CNS?
A
GABA & glycine
8
Q
What are glutamate, GABA and glycine made of?
A
Amino acids
9
Q
Opening of what channels allows receptor activation?
A
Voltage-activated Ca channels
10
Q
Which 2 ions are responsible for excitatory depolarisation & flow inward?
A
Na & Ca
11
Q
Which 2 ions ae responsible forinhibitory hyperpolarisation?
A
K & Cl
12
Q
How do local anaesthetics work?
A
Na antagonist - stop N flow leading to inhibition
13
Q
How do benzodiazepines work?
A
modulate GABA receptor so enhance Cl entry and enhance inhibitioninthepresence ofGABA
14
Q
What does glutamate do?
A
Acts on ionotropic receptors to allow Na & Ca in and K out of cell = EPSP, depolarisationandexcitation
15
Q
What does GABA do?
A
Acts on ionotropic receptors to allow Cl into the cell leading to inhibition
16
Q
What senses does the somatosensory system mediate?
A
All sensations that are not the special senses
17
Q
What is the receptive field of an afferent neurone?
A
Theregion that when stimulatedcauses aresponsein that neurone
18
Q
What do pacinian corpuscles sense?
A
Vibration
19
Q
How many sets of spinal nerves are there?
A
31
20
Q
Which roots areresponsible for sensory function?
A
Dorsalroots
21
Q
Which roots are responsible for motorf unction?
A
Ventral roots
22
Q
What is grey matter?
A
Cell bodies andsensry afferent terminals
23
Q
In which pathway do all fibres decussate together?
A
DCML pathway
24
Q
Where i the first synapse in the DCML pathway?
A
The brain stem
25
Where do fibres decussate in DCMLpathway?
All decussate together at the level of the brain stem
26
if the DCML was severed will the effects be on the same side or opposite?
Same side
27
How does the primary afferent travel to the brain stem in the DCML pathway?
Via gracile & cuneate tracts
28
What is stereogenesis?
The ability to recognise and object by feeling it
29
Where do neurones synapse in the A
| STT?
shortlyafter enteringspinalcord
30
Where do sensory fibres cross over in the STT?
All along the length of the spinal cord
31
If the STT is severed will sensation be lost on the same or opposite side?
Opposite side
32
How does general somatic info from the anterior head reach the brain?
Via trigeminal system
33
What are the 3 divisions of the trigeminal nerve?
V1 = ophthalmic
V2 = maxillary
V3 =mandibular
34
Where are the soma of sensory neurones of the face located?
Trigeminalsensory ganglion
35
Where does sensory input to T6 and above travel?
In the cuneate tract
36
Where does sensory info from below T6 travel?
In the gracile tract
37
Where is the somatosensory cortex located?
Post central gyrus of the parietal corte
38
What is the posterior parietal cortex responsible for?
Deciphering the deeper meaning of info in somatosensory cortex
39
What is the relationship between UMNs & LMNs?
UMNs supply input to LMNs to modulate their activity
40
What to LMNs recieve input from?
UMNs, proprioceptors & interneurons
41
Where are UMNs found?
The brain
42
How do axons of LMNs exit the spinal cord?
In the ventral roots or via cranial nerves
43
Which ype of skeletal muscle fibre has the largest a-MN?
Slow-oxidative (Type I) fibres
44
Why are Type-1 skeletal muscle fires red?
High myoglobin content
45
What is the myotatic reflex?
When skeletalmuscle ispulled itpullsback
46
What spinal levels are assessed by the knee jerk reflex?
L3-L4
47
What spinal level is assessed by the triceps reflex?
C7
48
Which spinal levels are assessed by the biceps reflex?
C5-C6
49
Which spinal levels are assessed by the supinator reflex?
C5-C6
50
Which spinal level is assessed by the gastrocenemius (ankle) reflex?
S1
51
Where are y-MN cell bodies located?
Ventral horn of the spinal cord
52
Where are golgi tendonorganslocated?
thejunctionofmuscleandtendon
53
What is thepurposeofgolgitendonorgans?
Protect muscle from overload
| Regulate muscle tension to optimal range
54
Where do descending spinal tracts originate?
Cerebral cortex & brain stem
55
Which pathways are under control from the cerebral cortex?
Lateral pathways
56
Which pathways are under control from the brainstem?
Ventromedialpathways
57
What is the major lateral pathway?
Corticospinal (pyramidal) tract
58
which hemisphere controls RIGHTmusculature?
LEFT hemisphere
59
Where do most fibres in the corticospinal tract decussate?
The pyramidal decussation at the base of the medulla
60
What des the rubrospinal tract control?
Limb flexor muscles
61
How could lesions of the lateralcolumnspresent?
Loss of 'fractionated' movements
Slowing and impairmentofaccuracy of voluntary movements
Little effect on normal posture
62
What is the function of the vestibulospinal tract?
Helps to hold upright and balanced posture by facilitating extensor MNs of anti-gravity muscles
63
Where do cell bodies from the tectospinal tract reside?
Superior colliculus
64
What muscles does the tectospinal tract influence?
Muscles of the neck, upper trunk and shoulders
65
Which is more medial the medullary or pontine reticulospinal tract?
Pontine
66
Where do both reticulospinal tracts arise from?
Reticular formation (mesh of neurones located along the length and core of the brainstem)
67
Which reticulospinal tract descends bilaterally?
Medullary
68
What is the function of the pontine reticulospinal tract?
Helps to maintain standing posture by facilitating contraction of the extensors of the lower limbs
69
What is the function of the medullary reticulospinal tract?
Releases antigravity muscles from reflex control
70
Where are cell bodies of nociceptors located?
Dorsal root ganglia
71
What is the character of visceral pain?
Poorly localised, dull, aching, throbbing
72
Why do patient get referred pain?
A some visceral & skin afferents converge on the same spinothalamic neurones
73
What is viscerosomatic pain?
When inflammatory exudate from a diseased organ contacts a somatic structure
74
Which of the nociceptive tracts is fast & which is slow?
STT = fast SRT = slow
75
How do STT & SRT differ?
```
STT = fast = warns exact location andseverity of pain
SRT = slow = registers the emotional/motivationalcomponent ofpain
```
76
What are the 3 mechanisms of actions of analgesic drugs?
```
Direct presynaptic inhibitions (stop Ca influx)
Direct postsynaptic inhibition (reduce excitability by opening K channels)
Indirect inhibition (activate inhibitory interneurones)
```
77
How do opiods work?
Couple to GPCOR to inhibit presynaptically by opening Ca chnnels and upress excitation postsynaptically by opening K channels
78
What are the 3 types of opioid receptor?
u
delta
Kappa
79
Which opioid receptor is responsible ofrmost of the analgesic actionsofopioids?
u receptor
80
What are the adverse effects of activating the u opioid receptr?
```
Respiratory depression
Cnstiation
Euphoria
Sedation
Dependence
```
81
What is the adverse effect of delta opioid receptors?
Proconvulsant
82
What is the difference between morphine & diamorphine?
Diamorphine ismore lipophillic
83
Which opioidagonist is given IV to provide analgesia in maintenance anaesthesia?
Fentanyl
84
Which opioid agonist is used in acute pain,particularly labour?
Pethidine
85
What should pethidine not beused in conjunction with? Why?
MAO inhibitors (excitement, convulsions, hyperthermia)
86
In which patients should tramadol be avoided?
Epilepsy
87
What is naloxone?
Competitive agonist of u -receptors used to reverse opioid toxicity
88
Which should care be taken when prescribing naloxone?
SHort half-life (opioids may have longer duration)
89
Why is naltrexone better than naloxone?
Much longer half-life
90
What should be given to a newborn displaying opioid toxicity as a result of pethidine given to the mother during labour?
Naloxone
91
How does paracetamol have analgesic effects?
Due toit'smetabolites
92
What is a adverse effect of selective COX-2 inhibitors?
They are prothrombotic
93
What damage can be caused by long term NSAID use
GI damage
94
Examples of drugs usedforneuropathicpain
Gabapentin
Pregabalin
Amitriptlline
Carbamazepine
95
How do gabapentin & pregabalin work?
Reduce surface area of a subunit of some voltage-gated Ca channels which are unregulated in damaged sensory neurones causing a decrease in neurotransmitters
96
What can gabapentin be used as prophylaxis for?
Migraines
97
What condition is pregabalin particularly useful in.
Painful diabetic neuropathy
98
How do amitriptyllinr ,nortryptilline & desipramine work?
Act centrally decreasing the reuptake ofnoradrenaline
99
How does carbamazepine work?
Blocks subtypes of voltage-activated Na channel that are unregulated in damaged nerve cells
100
What is carbamazepine first line in?
To control pain intensity & frequency of attacks in trigeminal neuralgia
