Anatomy and Tracts Flashcards
(138 cards)
1
Q
Broca’s area
A
Motor aspect of speech
Instructs muscles to form words
Located in the premotor cortex anterior to the precentral gyrus
2
Q
Broca’s aphasia
A
Also known as motor or non-fluent aphasia
Can understand speech and know what to say, but can’t form words
3
Q
Wernicke’s area
A
Sensory aspect of speech
Interprets tones
Located in the superior temporal gyrus
4
Q
Wernicke’s aphasia
A
Also known as sensory or fluent aphasia
Can’t interpret speech, but can form and speak words
5
Q
Exner’s area
A
Motor control of the hand
Located above the frontal eye fields in the premotor cortex anterior to the precentral gyrus
6
Q
Supramarginal gyrus
A
Related to reading
Located in the anterior parietal lobe
7
Q
Angular gyrus
A
Related to writing
Located in the posterior parietal lobe
8
Q
3 types of white matter tract
A
Association
Commissural
Projection
9
Q
Association fibres
A
Connections within the same hemisphere e.g. arcuate fasciculus
10
Q
Commissural fibres
A
Connections between the two separate hemispheres e.g. corpus callosum
11
Q
Projection fibres
A
White matter tracts that connect the brain and the nervous system below the brain e.g. corticospinal tract
12
Q
Connectional aphasia
A
Problem with the arcuate fasciculus causing disconnection between understanding speech and speaking
13
Q
Central sulcus
A
Large, deep groove separating the precentral and postcentral gyri
14
Q
Lateral fissure
A
Large, deep groove separating the temporal lobe from the frontal and parietal lobes
15
Q
Parieto-occipital sulcus
A
Hard to see groove separating the parietal lobe and the occipital lobe
Runs from the preoccipital notch up to the superior cortex
16
Q
Calcarine sulcus
A
Groove that runs from the very back of the brain, where the primary visual cortex is up to join the parieto-occipital sulcus
17
Q
Cingulate gyrus
A
Gyrus just superior to the corpus callosum involved in the hippocampal complex
18
Q
Septum pellucidum
A
Thin membrane separating the anterior horns of the left and right lateral ventricles of the brain inferior to the corpus callosum
19
Q
Cerebral aqueduct
A
Fluid-filled passage that links the 3rd ventricle under the thalamus to the 4th ventricle near the cerebellum
20
Q
Forebrain
A
Cortex, thalamus, hypothalamus
21
Q
Midbrain
A
Tectum, cerebral aqueduct, tegmentum, basis pedunculi
22
Q
Hindbrain
A
Cerebellum, pons, medulla, brainstem
23
Q
Describe the circle of Willis
A
The anterior cerebral arteries, which supply the anterior cortex, are connected by the anterior communicating artery. They end at the junction between the middle cerebral arteries and the internal carotid arteries. The posterior communicating arteries continues down and join the posterior cerebral arteries, which supply the occipital lobe. Coming out from under these are the superior cerebellar arteries, which join the basilar artery with smaller pontine arteries coming off either side. The larger anterior inferior cerebellar arteries come off after this and then the vertebral arteries branch off and descend down, further connected by the anterior spinal artery and branching the posterior inferior cerebellar artery.
24
Q
3 layers of the cortex
A
Neocortex (6 layers)
Allocortex (3 layers)
Archicortex (4 layers)
25
Layers of the neocortex from the outside in
(Pia mater)
Molecular – not a lot of neuronal input
External granular – lots of small (20 micron) granular fibres
External pyramidal – medium size, pyramidal shaped cell bodies
Internal granular – lots of slightly larger (40 micron) granular fibres
Internal pyramidal – lots of large (up to 160 micron) triangular cell bodies that form the pyramidal tract
Multiform – range of different cells that mainly project to and from the thalamus
26
What type of fibres would likely have cell bodies in level 5 of the neocortex?
Level 5 is the internal pyramidal layer, so efferent fibres are here, specifically projection fibres which have large cell bodies and tend to project to subcortical structures like the striatum, the thalamus, the medulla and the spinal cord.
27
What type of fibres would likely have cell bodies in level 4 of the neocortex?
Level 4 is the internal granular layer, so afferent fibres are found here, specifically corticopetal or specific afferent fibres e.g. from the thalamic relay nuclei.
28
What type of fibres would likely have cell bodies in level 3 of the neocortex?
Level 3 is the external pyramidal layer, so efferent fibres are found here, specifically association and commissural fibres for local networking.
29
What type of fibres would likely have cell bodies in level 2 of the neocortex?
Level 2 is the external granular layer, so afferent fibres are found here, specifically association and commissural afferents.
30
Basal ganglia
```
Sub-cortical grey structures consisting of:
Caudate nucleus
Globus pallidus
Substantia nigra
Putamen
Subthalamic nucleus
```
31
What makes up the striatum?
The globus pallidus and putamen
32
Describe the direct pathway linking the globus pallidus to the thalamus
Glutamate neurons from the cortex excite the putamen which synapse on inhibitory neurons on the internal globus pallidus which then synapse on the thalamus. This inhibits the excitatory glutamate neuron which travels back to the cortex, synapsing on upper motor neurons for movement. Dopamine neurons from the substantia nigra keep the putamen primed and inhibitory neurons go the opposite direction to keep this in balance.
33
Describe the indirect pathway linking the globus pallidus to the thalamus
Glutamate neurons from the cortex excite the putamen which synapse on inhibitory neurons on the external globus pallidus. Inhibitory neurons from the external globus pallidus synapse on the subthalamic nucleus which prevents overfiring of excitatory neurons from the subthalamic nucleus to the thalamus. This inhibits the excitatory glutamate neuron which travels back to the cortex, synapsing on upper motor neurons for movement. Dopamine neurons from the substantia nigra keep the putamen primed and inhibitory neurons go the opposite direction to keep this in balance.
34
Describe the effects of dopamine imbalance on the motor systems pathways
Because dopamine keeps the thalamus in a constant state of priming, dampening this prevents the inhibitory neurons from firing. As a result, GABA neuron 1 doesn't inhibit GABA neuron 2, which doesn't inhibit the glutamate neuron to the cortex, which is toxic. If lesions occur on either of the two first GABA neurons in the direct and indirect pathways, they are unable to fire and inhibit the inhibitory neuron. This fires more, inhibiting the glutamate neuron to the cortex, causing the first glutamate fibre to fire more to restore the balance, because the upper motor neurons aren't being excited enough, causing toxicity.
35
6 major thalamus nuclear groups
```
Anterior
Medial
Lateral
Intralaminar
Metathalamus
Ventral
```
36
Role of the anterior nuclear group
Connects to the frontal cortex for memory and emotional processing
37
Role of the medial nuclear group
Connects to the frontal and parietal association cortices for integration of sensory input
38
Role of the lateral nuclear group
Ventral: motor planning and sensory input from spinal cord
Lateral: integration of sensory input (same as medial nuclear group)
39
Role of the intralaminar nuclear group
Part of the reticular formation circuitry for consciousness and regulation of the sensitivity of gravity-opposing muscles
40
Role of the metathalamus
Lateral geniculate body: visual stimulus processing
| Medial geniculate body: auditory stimulus processing
41
Role of the ventral nuclear group
VA/VL: complete basal ganglia circuit by taking information from the globus pallidus, substantia nigra and cerebellum and process it and send it to the motor cortex
Posterior lateral: processes trigeminothalamic information and sends it to the somatosensory cortex
Posterior medial: processes medial lemniscus information and sends it to the somatosensory cortex
Posterior L + M: processes spinothalamic information and sends it to the somatosensory cortex
42
Describe the fibres of the internal capsule
The superior portion carries information to and from the frontal cortex
The genu contains facial motor fibres
Inferior to the genu on the lateral side are corticospinal motor fibres
Inferior to the genu on the medial side are sensory fibres that correspond to the areas of the motor fibres
43
General areas of grey matter
Dorsal horn – sensory
Ventral horn – motor
Intermediate grey horn – proprioception
Intermediolateral nucleus – autonomic
44
3 types of efferent fibres in the grey matter
Alpha motor neurons – sriated muscle
Gamma motor fibres – proprioception
Intermediolateral motor neurons – smooth muscle
45
Specific areas of grey matter
I – marginal zone, pain
II – Substantia gelatinosa, modulation of pain
III – IV – nucleus proprius, touch, pain and temperature
V – VI – referred, somatic and visceral pain
VII – contains dorsal nucleus of clarke (proprioception) and intermediolateral nucleus (visceral motor control)
VIII – interneurons
IX – LMNs going to skeletal muscle
46
4 funiculi of the spinal cord
Dorsal funiculus (including cuneate fasciculus and gracile fasciculus)
Ventral funiculus
2 lateral funiculi
47
In which funiculus is the anterior spinothalamic tract located?
The ventral funiculus
48
In which funiculus is the lateral spinothalamic tract located?
The lateral funiculus
49
In which funiculus are the spinocerebellar tracts located?
The lateral funiculus, the dorsal area for the dorsal spinocerebellar tract and the ventral area for the ventral spinocerebellar tract
50
In which funiculus is the anterior corticospinal tract located?
The ventral funiculus
51
In which funiculus is the dorsal column–medial lemniscus tract located?
The dorsal funiculus, specifically the cuneate fasciculus for the upper body and the gracile fasciculus for the lower body
52
Propriospinal tract
White matter tract separating the white matter of the spinal cord from the grey horn laterally
Provides communication between different levels of the spinal cord
53
Ventral white commissure
White matter tract in the separating the white matter of the spinal cord from the grey horn on the ventral side right in the middle. Lots of pathways and neurons pass through here.
54
Which specific areas of the grey horn do dorsal column neurons terminate in?
Some between areas V–VI and VII
Some in the dorsal nucleus of Clarke
Some in area IX
Some go straight up to the cortex without entering the grey horn
55
Which specific areas of the grey horn do anterior spinothalamic neurons terminate in?
Area V–VI
56
Which specific areas of the grey horn do lateral spinothalamic neurons terminate in?
Some in area I (marginal zone)
Some in area II (substantia gelatinosa)
Some in areas V–VI
57
How are the ventral root efferent cords arranged in the spinal cord?
They are arranged somatotopically, i.e., according to function. The lateral cord is responsible for distal muscles, the medial cord for proximal muscles, the dorsal cord for flexor muscles and the ventral cord for extensor muscles.
58
How are the lower motor efferent neurons arranged in the spinal cord?
Alpha motor neurons, which innervate striated muscle, originate from area IX, specifically the medial horn for axial LMNs and the lateral horn for limb LMNs.
Gamma motor neurons, which innervate muscle spindles (proprioception), originate from the interomediolateral nucleus.
Sympathetic preganglionic neurons, which inntervate smooth muscle via autonomic ganglia, originate from area IX.
59
3 types of interneuron
Intrasegmental – neurons within the same segment of the spinal cord
Intrasegmental commissural – neurons within the same segment but cross over to the other side
Intersegmental – neurons that travel within white matter to different segments for coordinated movements like walking
60
Describe the blood vessels of the spinal cord
A local artery sends off a spinal branch which branches into anterior and posterior radicular arteries. The anterior radicular artery gives rise to the anterior spinal artery which supplies the entire ventrolateral spinal cord. The posterior radicular artery gives rise to two posterior spinal arteries which supply the dorsal funiculus. The veins are the same.
61
Posterior cord syndrome
Occurs when posterior spinal artery is damaged causing loss of fine touch; pain sensation is not affected.
62
Anterior cord syndrome
Occurs when anterior spinal artery is damaged causing loss of motor function, pain sensation and crude touch; fine touch is not affected.
63
List the cranial nerves in order
```
Olfactory
Optic
Occulomotor
Trochlear
Trigeminal (ophthalmic, maxillary, mandibular)
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal
```
64
List the general roles of the facial nerves
```
Olfactory – Sensory
Optic – Sensory
Occulomotor – Motor
Trochlear – Motor
Trigeminal (ophthalmic, maxillary, mandibular) – Both
Abducens – Motor
Facial – Both
Vestibulocochlear – Sensory
Glossopharyngeal – Both
Vagus – Both
Accessory – Motor
Hypoglossal – Motor
```
65
Cranial nerves found in the allocortex
Olfactory and optic
66
Cranial nerves found in the midbrain
Occulomotor and trochlear
67
Cranial nerves found in the pons
Trigeminal, abducens, facial, vestibulocochlear
68
Cranial nerves found in the medulla
Glossopharyngeal, vagus, accessory, hypoglossal
69
GSS
General somatic sensory
70
GVS
General visceral sensory
71
SSS
Special somatic sensory
72
SVS
Special visceral sensory
73
GSM
General somatic motor
74
GVM
General visceral motor
75
SVM
Special visceral motor
76
Olfactory nerve modality
SVS
77
Optic nerve modality
SSS
78
Occulomotor nerve modality
GSM and GVM
79
Trochlear nerve modality
GSM
80
Abducens nerve modality
GSM
81
Trigeminal (ophthalmic) nerve modality
GSS
82
Trigeminal (maxillary) nerve modality
GSS
83
Trigeminal (mandibular) nerve modality
GSS and SVM
84
Trigeminal neuralgia
Chronic pain disorder affecting the trigeminal nerve
| Episodic, unilateral, shock-like pain that tends to increase in severity over time and can be debilitating
85
Trigeminal neuralgia causes
Pressure on the trigeminal nerve e.g., contact with blood vessel or tumour
Aging, degradation of myelin sheath
86
Trigeminal neuralgia treatment
Anticonvulsants, muscle relaxants, botox, microvascular decompression, rhizotomy
87
Facial nerve modality
SVM, GVM, SVS
88
Bell's palsy
Muscles on one side of face are weak or paralysed causing stiffness and drooping
89
Bell's palsy causes
Trauma or pressure on facial nerve
| Viral infection
90
Bell's palsy treatments
Corticosteroids and antivirals
91
Vestibulocochlear nerve modality
SSS
92
Glossopharyngeal nerve modality
GSS, GVS, SVS, GVM, SVM
| Innervates salivary glands, posterior tongue (taste and sensation), carotid body and sinus and swallowing muscles
93
Vagus nerve modality
GSS, GVS, SVS, GVM, SVM
| Larynx, pharynx, thoracic and abdominal viscera, epiglottis, smooth muscle of GI tract
94
Accessory nerve modality
GSM
95
Hypoglossal nerve modality
GSM
| Innervates tongue muscles
96
Corneal reflex
Blinking (consensual – happens both sides)
Afferent = trigeminal nerve
Efferent = facial nerve
97
Pupillary reflex
Constriction when exposed to light
Afferent = optic nerve
Efferent = occulomotor nerve
98
Gag reflex
```
Afferent = glossopharyngeal nerve
Efferent = vagus nerve
```
99
What structure does the olfactory nerve pass through?
The cribiform plate
100
What structure does the optic nerve pass through?
The optic canal
101
What structure does the occulomotor nerve pass through?
The superior orbital fissure
102
What structure does the trochlear nerve pass through?
The superior orbital fissure
103
What structure does the trigeminal nerve pass through?
Ophthalmic: superior orbital fissure
Maxillary: foramen rotundum
Mandibular: foramen ovale
104
What structure does the abducens nerve pass through?
The superior orbital fissure
105
What structure does the facial nerve pass through?
Internal acoustic meatus
106
What structure does the vestibulocochlear nerve pass through?
Internal acoustic meatus
107
What structure does the glossopharyngeal nerve pass through?
The jugular foramen
108
What structure does the vagus nerve pass through?
The jugular foramen
109
What structure does the accessory nerve pass through?
The jugular foramen
110
What structure does the hypoglossal nerve pass through?
The hypoglossal canal
111
What output structure and cerebellar system are associated with the archicerebellum?
The fastigial nucleus and the vestibulocerebellum
112
What output structure and cerebellar system are associated with the palaeocerebellum?
The interpositus nucleus and the spinocerebellum
113
What output structure and cerebellar system are associated with the neocerebellum?
The dentate nucleus and the cerebrocerebellum
114
Describe the pathway of inputs and outputs via the fastigial nucleus
A balance/eye movement signal goes up the spinal cord into the vestibular nucleus in the inferior pons which then relays a signal into the cortex of the cerebellum. This is processed and sent back to the deep cerebellar nucleus the fastigial nucleus located in the vermis (and flocculonodular lobe) in the archicerebellum. Both the fastigial nucleus and the flocculonodular lobe send a signal back to the lateral vestibular nucleus which utilises the vestibulospinal tract to get to the lower motor neuron pool. The fastigial nucleus also sends a signal to the reticular formation which travels down the reticulospinal tract to the lower motor neuron pool.
115
Describe the pathway of inputs and outputs via the interpositus nucleus
A balance/posture signal goes up the spinal cord via the dorsal spinocerebellar tract into the cortex of the cerebellum. This is processed and sent back to the deep cerebellar nucleus the interpositus nucleus located in the palaocerebellum. This sends a signal to the red nucleus in the midbrain which then utilises the rubrospinal cord to take the signal to the lower motor neuron pool.
116
Describe the pathway of inputs and outputs via the dentate nucleus
A coordination signal goes up the spinal cord via the inferior olivary nucleus which then relays that signal to the cerebellar cortex for processing. It then travels to the deep cerebellar nucleus the dentate nucleus, which trasmits it to the red nucleus in the midbrain and also to the thalamus. Both areas then send the signal along upper motor neurons in areas 4 and 6 in the grey horn, then to the lower motor neuron pool.
117
Olfactory trigone
Where the olfactory inputs enter the brain
118
Describe the limbic system
The olfactory bulb ends at the olfactory trigone, where two branches end at the lateral amygdaloid complex and the septal nuclei, which are joined together by the stria terminalis. The septal nuclei also is connected to the substantia nigra by the medial forebrain bundle.
119
Another name for medial forebrain bundle
Nigrostriatal pathway
120
Medial septal nuclei
Inferior part of caudate nucleus
121
Lateral amygdaloid complex
Where the end of the olfactory bulb is when the olfactory tract stops—generally referred to as the amygdala
122
Describe the hippocampal complex
The dentate gyrus sits next to the parahippocampal gyrus and via the fornix transmits information around the corpus callosum to the mammillary bodies. The mammillary bodies are connected to the anterior thalamic nucleus by the mammillothalamic tract, The fornix also branches out near the end around the anterior commissure to connect to the septal nuclei of the limbic system.
123
Papez's circuit
```
Parrahippocampal gyrus -->
Hippocampus -->
Fornix mammillary body -->
Anterior thalamic nucleus -->
Cingulate gyrus -->
Frontal cortex -->
Cingulate gyrus -->
Parahippocampal gyrus
```
124
What structure produces norepinephrine?
Locus coeruleus (in the pons)
125
What structure produces serotonin?
Raphe nucleus (in the tegmentum of the pons)
126
General astrocyte role
Innate immune response – Release pro- and anti-inflammatory molecules, phagocytose and form scars
127
General microglia role
Surveyors of brain's microenvironments – resident macrophages of the brain
128
4 different types of astrocyte
Protoplasmic
Interlaminar
Fibrous
Polarised
129
Protoplasmic astrocyte
Most common type, reside in layers 2–6 of cortex. GFAP processes do not overlap. Regulate blood flow in response to increased synaptic transmission.
130
Fibrous astrocyte
Found in white and grey matter. Processes intermingle – they don't form a domain structure. Support role for neurons and respond to brain injury.
131
Microglia and Alzheimer's
Studies have found that microglia have the ability to phagocytose amyloid plaques in AD but so far there has been no increase in cognition
132
Reticular formation
A collection of about 100 nuclei in the tegmentum which is partitioned into different roles:
In the midbrain it is responsible for arousal and awareness
In the pons it is responsible for controlling eye movement and posture
In the medulla it is responsible for involuntary movement of the GI, CV and respiratory systems
133
Pericytes in the brain
Encase endothelial cells in brain capillaries and instruct them to for the blood brain barrier
134
Neurotransmitters
Released from pre-synaptic terminal to act on post-synaptic neuron and produce relatively fast inhibitory or excitatory effects
135
Neuromodulators
Produce slower pre- and post-synaptic responses. Released by nerve cells and astrocytes.
136
Neurotrophic factors
Released by non-neuronal cells and neurons and work over long time scales. Act on tyrosine kinase receptors.
137
Fast acting neurotransmitters
Work via ion channels e.g. GABA, glutamate
138
Slow acting neurotransmitters
Work via GPCRs e.g. dopamine, acetylcholine, GABA
