Module 1 - Nervous System Flashcards
1
Q
human vs other mammalian brain
A
- fundamental organisation same (forebrain, midbrain, hindbrain)
- human larger, more complex (esp forebrain for wide range of complex behavioural/cognitive functions)
2
Q
lobes of the brain
A
- frontal
- parietal
- occipital
- temporal
3
Q
premotor / planning cortex function
A
execution of movement
4
Q
exner’s area function
A
responsible for hand movement
5
Q
frontal eye fields function
A
responsible for eye movement
6
Q
broca’s area function
A
responsible for speech
- only localised in left
7
Q
frontal association cortex function
A
- intelligence
- personality
- behaviour
- mood
- cognitive function
8
Q
homunculus
A
“small human”
- map representing sensory/motor neurons in each body part
9
Q
broca’s / motor / nonfluent aphasia
A
can’t speak but can give written response
- previously considered psychiatric
10
Q
supramarginal gyrus function
A
reading
11
Q
angular gyrus function
A
writing
12
Q
SMAGLA function
A
learning areas
- language
- planning
- handwriting
- eye movement (e.g when reading)
13
Q
parietal association cortex function
A
- spatial skills
- 3D recognition
– shapes
– faces
– concepts
– abstract perception (e.g written words)
14
Q
primary auditory cortex function
A
responsible for breaking sounds up into different tones/timings
15
Q
wernicke’s area function
A
responsible for interpretation of speech
16
Q
temporal association cortex function
A
- memory
- mood
- aggression
- intelligence
17
Q
secondary visual cortex function
A
makes things up to make sense
18
Q
arcuate fasciculus
A
- bundle of white matter
- goes inside and comes out at broca’s
19
Q
connectional aphasia
A
can understand/fluent but can’t connect
- speech has no correlation to what is understood
- difficult to find whether it’s dysfunctional
e.g dyslexia
20
Q
components of hindbrain
A
- pons
- medulla (oblongata)
- cerebellum
21
Q
components of brainstem
A
- midbrain
- pons
- medulla
22
Q
corpus callosum
A
white matter that takes info between right/left side of brain
=> coordination that allows e.g catching ball with both hands
- large in humans/primates while different animals have other ways
23
Q
left hemisphere (dominant hemisphere)
A
dominant hemisphere for language
- only 20% of left handed people are right side dominant
24
Q
right hemisphere function
A
- Non-verbal language (e.g. body language)
- Emotional expression (tone of language)
- Spatial skills (3D)
- Conceptual understanding
- Artistic/Musical skills
25
effects of injury on right hemisphere
- Loss of non-verbal language
- Speech - lacks emotion
- Spatial disorientation
- Inability to recognise familiar objects
- Loss of musical appreciation
26
sensory info path
skin -> spinal cord -> brain
27
motor info path
brain -> spinal cord -> skin
28
dermatome
map in the body that indicates the area of skin in which sensory nerves derive from a single spinal nerve root
29
protective structures of spinal cord
1) vertebrae of vertebral column
2) cerebrospinal fluid
3) meninges
30
meninges
three protective, connective tissue coverings that encircle the spinal cord and brain
- pia mater
- arachnoid mater
- dura mater
31
pia mater feature
so tightly bound to spinal cord that they can't dissociate
32
nerves in the spinal cord
1) 8 cervical nerves
2) 12 thoracic nerves
3) 5 lumbar nerves
4) 5 sacral nerves
5) coccygeal nerve
=> 31 paired nerves
33
cervical nerves
8 spinal nerves despite 7 vertebrae
- out from vertebrae to local area
- greatest narrowing here
34
thoracic nerves
each corresponds to each thoracic vertebra AND paired with each rib
35
spinal cord ends at
lumbar vertebra 1
36
cauda equina
all below lumbar vertebra 1
- good place for anaesthetics as needle less likely to hit spinal cord and cause permanent damage
37
sacral nerves
5 fused vertebra
=> saccrum
38
coccygeal nerve
coccyx
- semiarticulated point
39
neurons in cauda equina
bathed in cerebrospinal fluid
40
anatomical location of motor and sensory components
motor component located anatomically in front and sensory component at back as motor cortex in front of sensory cortex
41
nondiscriminitive (pain and temperature)
less frequently used
- free nerve endings (no encapsulation)
- unmyelinated
- 1 ms-1 conduction velocity
- synapses at opioid receptor
42
opioid receptor
- specific for unmyelinated neurons
- can readily cause neurons to shut down
43
discriminitive sensation information
ability to tell two different points of touch apart
- depends on proportion of space taken up by primary somatosensory homunculus
44
discriminitive (touch and pressure)
- pseudounipolar neurons
- encapsulated end
- myelinated
- 50 ms-1 conduction velocity
- some go into grey matter and other in white matter
45
if discriminitive have no myelin
neurons wear themselves out due to energy required to conduct
46
corpuscle for touch
meissner's corpuscle
47
corpuscle for pressure
paccinian corpuscle
48
convergence
where one neuron picks up info from hundreds of neurons
=> way of keeping spinal cord much smaller
49
column
bundle of white matter
50
dorsal root ganglion
big group of cell bodies related to dorsal root
51
ventral root
carry motor info out to muscle
52
lateral motor columns/funinculus
info from brain to spinal cord
53
area 8+9 (motor neuron pool)
where lower motor neurons are (join to brain)
54
intermediate area
- balance, posture, returning back to midline
- autonomic nervous system (nervous supply to and from organ): beating heart, bladder, gastrointestinal
55
area 3+4 (nucleus proprius)
proprioception: ability to tell what's happening in peripheries
- areas 3 and 4 are functionally same due to same cell type
56
area 1+2
- where pain/temperature fibres are found
- gelatinous
57
ventral funinculus
responsible for pain and temperature
58
cuneate fasciculus
carries upper limb info
59
gracile fasciculus
carries lower limb info
60
configuration of cuneate/gracile fasciculus
depends on where on the spinal cord
e.g don't need area for arms at lower end of spinal cord
61
myotactic reflex
happens without brain knowing
- e.g when walking
fastest reflex
62
two sensory systems
1) dorsal column - medial lemniscal system
2) lateral spinothalamic pathway
63
dorsal column - medial lemniscal system
- pathway for discriminative sensation
- decussates at internal arcuate fibres
- primary neuron synapses at cuneate/gracile nuclei
- secondary neuron goes through medial lemniscus in pons
- secondary neuron synapses at ventro-posterior nuclei in thalamus
- tertiary neuron goes through internal capsule
64
thalamus
determines what the cortex will understand given everything else that's going on
65
tract of lissauer
transparent due to no coloured myelin
66
lateral spinothalamic pathway
- pathway for pain and temperature
- decussates at anterior white commissure
- primary neuron synapses at area 1+2
- secondary neuron goes through spinothalamic tract
- secondary neuron synapses at ventro-posterior nuclei in thalamus
- tertiary neuron goes through internal capsule
67
discriminative and nondiscriminative pathways come back together
for the first time at the level of pons
68
lesion
damage; tumour; abnormal area of tissue that may get bigger
69
lesion in brain/brainstem (right side)
loss of:
- left touch and pressure
- left pain and temperature
same side as both have already decussated
=> associative sensory loss
70
lesion in spinal cord (right side)
loss of:
- right touch and pressure (left unaffected)
- left pain and temperature
opposite sides as only pain and temperature has decussated
=> dissociative sensory loss
71
left spastic paralysis
- primary motor cortex (located in precentral gyrus in frontal lobe) damage
- right hemisphere
72
loss of sensation in left hand
- primary somatosensory cortex (located in postcentral gyrus in parietal lobe) damage
- right hemisphere
73
loss of hearing in left ear
- primary auditory cortex (located in superior temporal gyrus) damage
- right hemisphere
74
problems with non-verbal communication
- non-dominant (right for most) hemisphere damage
- parietal association cortex most likely affected
75
motor system of brain function
voluntary movement
76
Betz cells / pyramidal neurons dimensions
- 1.2 m long (longest fibre - down to spinal cord)
- cell body 160 microns (average cell in brain is 20 microns)
77
lesion in brainstem
- LMN work under reflex control
- stiffening
- spastic paralysis
78
spastic paralysis
- can't control level of pressure
- rigidity/unable to relax
79
lesion in spinal cord
- LMN affected
- flaccid paralysis
80
flaccid paralysis
no control
81
lesion in left part of cerebellum
uncoordinated movement on left
82
lesion in left basal ganglia
unrefined movement on right
83
5 nuclei in basal ganglia
in the forebrain:
1) caudate nucleus
2) putamen
3) globus pallidus
4) subthalamic nucleus
in the midbrain:
5) substantia nigra
84
basal ganglia circatory
responsible for fine movement control
e.g writing, shaping mouth for speech
85
striatum
caudate nucleus + putamen fused together (can't pull apart) => difficult to distinguish between the components
86
thalamus
not part of basal ganglia but part of circuit
- informed about upcoming movements in the basal ganglia
- happens before pyramidal pathway
87
pyramidal pathway aka
corticospinal tract
88
substantia nigra
- 85-90% of brain's dopamine produced
- big component of midbrain
89
segments of globus pallidus
external and internal segments
- act like different nuclei
90
globus pallidus
pale circular structure
91
putamen
technically connected to caudate nucleus
92
cerebellum and spinal cord
direct output to spinal cord
93
cerebellum function
- adjust movement to account for discrepancy between planned/actual movement
- maintain balance
- coordinate, map, terminate movement and work with unconscious movement
- ability to stop movement at specific point
94
basal ganglia system and spinal cord
no direct input/output to spinal cord
95
basal ganglia system function
- initiation of movement
- refining for more controlled, smoother, precise movement after practice
- convey mood through movement
- strategy for when plan goes wrong
96
parkinson's disease symptoms
- difficulty initiating movement
- bradykinesia / hypokinesia
- tremor at rest
- stiffness / rigidity
- emotionally flat mood
97
parkinson's disease pathology
60-80% of dopamine-producing neurons in substantia nigra are gone
=> 3 inhibitory neurons in striatum unable to be activated
=> inhibitory neurons from internal segment of globus pallidus uncontrolled (always active)
=> hypoexcitability of neurons from thalamus to premotor cortex
=> hypoactivity
98
parkinson's disease treatment
1) levodopa drug
2) pallidotomy
3) thalamotomy
4) deep brain stimulation
99
levodopa drug
- precursor to dopamine
- allows remaining 20% of cells to produce dopamine
100
high dopamine levels
- depression
- psychosis (e.g hallucination)
- excessive reward
101
low dopamine levels
- rigidity
- stiffness
102
parkinson's disease and schizophrenia
- high dopamine level symptoms = schizophrenia symptoms = parkinson's disease patients on levodopa drug
- low dopamine level symptoms = parkinson's disease symptoms = schizophrenic patients on drugs
103
pallidotomy
surgical procedure that cause lesions to internal globus pallidus to destroy parts that generate tremors/muscle rigidity (overactive inhibitory cells)
104
deep brain stimulation
using electrical currents released by implanted electrodes (from a probe) to restore movement control
- either subthalamic nucleus or globus pallidus interna
105
corticospinal tract
pyramidal neuron at motor cortex -> goes through internal capsule -> corticospinal tract (pons) -> deviate from column into bunds to bend around pontine nuclei -> lower medulla -> 85% cross over at pyramidal decussation -> lateral motor column -> motor neuron pool OR 15% anterior corticospinal tract -> decussate at anterior white commissure (spinal segmental level) -> motor neuron pool
106
85% of motor neurons
typically innervate peripheral skeletal muscles of limbs and trunk
107
15% of motor neurons
typically innervate large, course muscles of axial skeleton
108
motor neurons to face
exit pons to face
109
paraplegia
paralysis of lower body
110
quadriplegia
paralysis of neck down
111
ataxia
impaired coordination => cerebellum
