Week 1 HNN lectures Flashcards
1
Q
What does the altar plate turn into?
A
A place of sensory functions
2
Q
What does the basal plate turn into?
A
An area of motor function
3
Q
Where are the cell bodies of motor neurons found?
A
The ventral horn of the grey matter
4
Q
What is found in the ventral horn?
A
The cell bodies of motor neurons
5
Q
Where are the temperature pathways found?
A
The ventral funiculus
6
Q
What is found in the ventral funiculus?
A
Temperature pathways
7
Q
What type of matter is the ventral funiculus made up of?
A
White matter
8
Q
What is the outermost of the meninges?
A
The Dura mater
9
Q
Where are epidural spaces found?
A
Between the dura and the vertebrae
10
Q
What is the middle meningeal layer?
A
The arachnoid mater
11
Q
What is CSF?
A
A filtrate of the blood
12
Q
Where is CSF made?
A
In the choroid plexus within the ventricular system of the brain
13
Q
What is the function of CSF?
A
To give the brain and spinal cord mechanical and immunological protection
14
Q
What is the innermost meningeal layer?
A
The pia mater
15
Q
What is a major route for spread of cancer from deep pelvic regions?
A
Batson veins
16
Q
What is the blood supply for the lower 1/3 of the spinal cord?
A
The artery of Adamkiewicz
17
Q
What does the artery of Adamkiewicz supply?
A
The lower 1/3 of the spinal cord
18
Q
Where does the artery of Adamkiewicz arise from?
A
The left posterior intercostal artery (in 70% of people)
19
Q
Where are epidural injections usually inserted?
A
Into the epidural space at either L3/L4 or L4/L5 vertebral level
20
Q
What type of fibres transmit pain?
A
Ad and C fibres
21
Q
Where does pain input enter the spinal cord?
A
The superficial dorsal horn
22
Q
Where does touch input enter the spinal cord?
A
The deep dorsal horn
23
Q
What type of fibres transmit touch
A
Ab fibres
24
Q
What is the function of the neuron?
A
It is a communicating unit of the nervous system
25
How do neurons communicate?
Via action potentials and synaptic transmitters
26
Why does a resting membrane potential arise?
Due to a difference in charge (due to ions) between the inside and outside of the neuron
27
What is the typical RMP (resting membrane potential) of ions?
-60 to -70 mV
28
How do ions cross the membrane?
Via ion channels
29
How are voltage gated channels controlled?
Depending on membrane potential
30
How are ligand gated channels controlled?
In response to binding or activation by a neurotransmitter or drug
31
What is an action potential?
A brief but dramatic change in membrane potential
32
What are action potentials used for ?
Neurons use action potentials to communicate information
33
What happens if the depolarisation is too small and doesn't reach the threshold?
The membrane potential returns to normal and no action potential is fired
34
What happens when the depolarisation is big enough and the threshold is reached?
An action potential is released
35
What ion is related to depolarisation?
sodium ions
36
What ion is related to repolarisation and hyperpolarisation?
Potassium ions
37
What happens for depolarisation to occur?
Fast opening of voltage gated Na channels
38
What happens for repolarisation or hyperpolarisation to occur?
Slow opening of voltage gated K channels
39
How do local anaesthetics (e.g. lidocaine) work?
It is a Nav blocker that means when nerve damage occurs the nerves in the skin can't release action potentials
40
What are the two ways positive charge can travel?
1. along an axon
| 2. out of the axon via the membrane
41
What does the destination of the current depend on?
1. axon diameter
| 2. number of open pores/ channels in the membrane
42
Are small diameter axons high or low resistance?
High
43
Are large diameter axons high or low resistance?
Low
44
What does it mean If there are lots of open pores or channels on an axon?
The charge can leak out of the axon
45
What does it mean when there aren't many open channels on an axon?
Charge wont leak out as readily
46
What is myelin?
A fatty white substance that prevents the leaking of charge
47
what makes myelin?
Schwann cells and oligodendrocytes
48
Where is myelin found?
Some axons are insulated by myelin
49
How do action potentials move along myelinated axons?
It jumps from node to node on the myelinated axon
50
What is the difference between myelinated and unmyelinated fibres?
Myelinated fibres conduct action potentials much faster than unmyelinated fibres
51
What causes MS?
Antibodies attack the myelin
52
What is an EPSP?
An excitatory postsynaptic potential
53
What does an EPSP do?
Brings the post synaptic membrane closer to threshold which makes it more likely that the cell will produce an action potential
54
What is an IPSP?
An inhibitory postsynaptic potential
55
What does an IPSP do?
Moves the post synaptic membrane potential further away from threshold which reduces the likelihood of an action potential being produced
56
What is temporal summation?
The frequency of firing of action potentials
57
What is spatial summation?
Firing at multiple sites of action potentials
58
What are the types of neurotransmitter?
Cholinergic, Biogenic amines, Amino acids, Neuropeptides and miscellaneous
59
What is divergence?
When one neuron communicates with many
60
What is it called when one neuron communicates with many others?
Divergence
61
What is convergence?
when many neurons communicate with one
62
What is it called when many neurons communicate with one?
Convergence
63
What is an EEG?
Electro-encephalography
64
What is PET?
Positron emission tomography
65
What is fMRI?
Functional magnetic resonance imaging
66
what is TMS?
Transcranial magnetic stimulation
67
What does an EEG do?
It records the electrical activity of the brain
68
What does PET do?
Measures blood flow, via a small dose of radioactive material injected into the bloodstream
69
What does fMRI do?
Measures blood flow
70
What does TMS do?
Uses electromagnet to stimulate brain activity, causing depolarisation or interrupted firing
71
What is EEG used for?
To investigate cognitive processes in response to a stimulus
72
What is PET used for?
Locates brain activity while performing a task
73
What is fMRI used for?
Locates brain activity while performing a task
74
What is TMS used for?
Interrupts brain activity while performing a task
75
By what stage of gestation will the majority of neurons be present?
10-11 weeks
76
What is a heterotopia?
An area of neural tissue that isn't in the right place
77
Where are movements planned?
The cerebellum
78
What area of the brain allows us to react quickly to the environment?
The cerebellum
79
What does the cerebellum allow us to do?
Plan movements and react quickly to the environment
80
What area of the brain does everything pass through?
The midbrain
81
What is a sulcus
A groove
82
What is a gyrus
A fold
83
What is in the sagittal sulcus?
The sagittal sinus and a thin sheet of dura mater
84
What function is in the precentral gyrus?
Motor
85
What function is in the postcentral gyrus?
Sensory
86
How do the motor and sensory homunculs lie in respect to each other?
Parallel
87
What is in Brocca's area?
Motor aspects of speech and speech associated gestures
88
Which hemisphere is Brocca's area most commonly found?
The left hemisphere
89
Why is the Brocca's area most commonly found in the left hemisphere?
Because most people are right handed
90
What happens if there is damage to Brocca's area?
Extensive aphasia - non-fluent, slow speech
91
What happens in Wernicke's area?
Sensory language area, lexical processing
92
Where is Wernicke's area?
In the dominant cerebral hemisphere (left in 90% of the population)
93
What happens if there is damage to Wernicke's area?
Receptive aphasia - extremely poor comprehension (you can't understand speech)
94
What do the basal ganglia do?
Influence motor activity and motor control
95
What is the function of the lateral ventricles?
They provide cushioning
96
Where do the lateral ventricles drain into?
The third ventricle and eventually onwards to the spine
97
What information does the Medial Lemniscal pathway transmit?
Touch
98
What information does the spinothalamic pathway transmit?
Pain
99
What is it thought that claustrum neurones have something to do with?
Consciousness
100
What is the widest type of nerve fibre?
Aa
101
What is the fastest type of nerve fibre?
Aa
102
What is the second widest type of nerve fibre?
Ab
103
What is the second fastest type of nerves fibre?
Ab
104
What is the thinnest type of nerve fibre?
C
105
What is the slowest type of nerve fibre?
C
106
What is the order (widest to thinnest) of the nerve fibres?
Aa, Ab, Ad, C
107
What is the order (fastest to slowest) of the nerve fibres?
Aa, Ab, Ad, C
108
What do Aa fibres transmit?
Proprioception
109
What do Ab fibres transmit?
Touch in skin
110
What do Ad receptors transmit?
Pain, temperature
111
What do C fibres transmit?
Temperature, pain, itch
112
Why are C fibres slower than the other fibres?
They are not myelinated
113
What are the ascending tracts of white matter?
Sensory
114
What do the descending tracts of white matter do?
Modulate activity
115
Where in the sensory pathway does the primary neuron synapse to the secondary neuron?
In the spinal cord or brainstem
116
Where in the sensory pathway does the secondary neuron synapse to the tertiary neuron?
In the thalamus
117
Where does the tertiary neuron travel to?
The cerebral cortex
118
What type of mechanoreceptors detect light touch?
Meissner's corpuscle and Merkel disks
119
What types of mechanoreceptors detect pressure?
Pacinian corpuscles and Ruffini endings
120
Where is the medial Lemniscal pathway?
Dorsal column
121
What does the medial Lemniscal pathway transmit?
Discriminative tactile sensation (touch)
122
What does the spinothalamic pathway transmit?
Pain, temperature, crude touch
123
Where does the primary neuron synapse to the secondary neuron in the pain pathway?
The dorsal root in the spinal cord
124
Where does the secondary neuron synapse to the tertiary neuron in the pain pathway?
In the thalamus
125
What does the corticobulbar pathway transmit?
Motor control (voluntary) and innervation of the cranial nerve nuclei
126
Where are action potentials for the corticobulbar pathways generated?
The motor cortex
127
Where does the upper motor neuron go?
The pons or medulla
128
Where does the lower motor neuron go?
The muscle that is being triggered
129
Where do the neurons from the corticospinal pathway cross over?
The pyramidal decussation
130
What descending tracts control voluntary motor movement?
Corticospinal and corticobulbar tracts
131
What descending tracts control muscle tone?
Reticulospinal, tectospinal and vestibulospinal
132
What does the reticulospinal pathway control?
Extensors and flexors
133
What are the two sections of the reticulospinal pathway?
Pontine tracts and medullary tracts
134
What does the pontine tracts control?
Extensors
135
What does the medullary tracts control?
Flexors
136
What does the vestibulospinal pathway control?
Modulates the activity of alpha-motor neurons and is important in the maintenance of balance and posture
137
What does damage/pathology of the vestibulospinal pathway lead to?
Loss of postural control
138
Where does the tectospinal pathway run?
Ventromedially
139
Where does the tectospinal pathway originate?
Contralateral superior colliculus (mid-brain)
140
What is the function of the tectospinal pathway?
Innervates muscles of the neck and modulates activity of alpha and gamma neurons
141
What is the purpose of pain?
Survival - protective
142
What negative effects can pain have on the body?
- CNS - anxiety, depression, sleep impairment
- CVS - inhibits cough, hyperventilation
- GI - nausea, vomiting
- GUS - urinary retention, uterine inhibition
- muscle - restless, immobility
143
What is nociception?
The mechanism by which we detect the presence of a potentially tissue harming stimulus
144
What are the four physiologic processes involved in nociception?
Transduction, transmission, modulation and perception
145
Where are nociceptors found?
Skin, bone, muscle, internal organs, blood vessels
146
Where are nociceptors not found?
The brain
147
What type of fibres detect temperature?
C and Ad
148
What type of fibres transmit pain?
C and Ad
149
What type of fibres transmit touch?
Ab
150
What are the two levels of pain modulation?
Spinal and supra-spinal
151
what is neuropathic pain?
Pain that is initiated or caused by a primary lesion or dysfunction in the peripheral or central nervous system
152
What can cause neuropathic pain?
Post-surgical and post-traumatic nerve injury
153
Where is pain felt in peripheral neuropathic pain?
In the territory of the affected nerve or nerve root
154
Where is pain felt in central neuropathic pain?
It is related to the site of the lesion in the spinal cord or brain
155
What are the characteristics of somatic pain?
- Site - well localised
- Radiation - dermatomal
- Character - sharp, aching, gnawing
- Periodicity - constant +/- incident
- Associations – rarely
156
What are the characteristics of visceral pain?
- vague distributiom
- diffuse, to body surface
- dull, cramp, dragging
- often periodic
- nausea, sweaty, HR & BP
157
What are the 6Ps of pain relief?
```
Prevention
Pathology
Physical therapy
Pharmacotherapy
Procedural
Psychology
```
158
What are the steps on the WHO ladder for analgesic pain relief?
Step 1 - Paracetamol, NSAIDs or cox II inhibitors
Step 2 - Codeine, Dihydrocodein (often as co-analgesics)
Step 3 - Morphine, oxycodone, tramadol, buprenorphine, fentanyl
