Neuroanatomy Flashcards
(177 cards)
1
Q
The nervous system can be divided into…
A
CNS: brain and spinal cord
PNS: 12 pairs of cranial nerves and 31 pairs spinal nerves and branches
2
Q
What is the first structure the brain develops from?
A
Neural tube
3
Q
What primary vesicles does the neural tube divide into? When does this occur?
A
Prosencephalon
Mesencephalon
Rhombencephalon
4 weeks
4
Q
What secondary vesicles are formed from the primary vesicles of the brain? When does this occur?
A
1st and 3rd divide at 6-8 weeks:
Prosencephalon forms telencephalon and diencephalon
Mesencephalon remains the same
Rombencephalon forms melencephalon and mylencephalon
5
Q
What structures of the brain evolve from the 5 secondary vesicles?
A
Top - toe order... Telencephalon ---> Cerebral hemispheres Diencephalon ---> Thalamus, hypothalamus Mesencephalon ---> Midbrain Melencephalon ---> Pons, cerebellum Myelencephalon ---> Medulla oblongata
6
Q
What are the components of the brainstem?
A
Midbrain
Pons
Medulla oblongata
7
Q
What is the role of neurones, principle cells of the CNS?
A
‘Communicators’ that recieve info via synapses, integrate it and then transmit electrical impulses to another neurone or effector cell
8
Q
Most neurones are multipolar/ unipolar?
A
Multipolar
9
Q
What is the basic structure of a neurone?
A
Dendrites
One axon
Cell body
10
Q
What are the four types of glial ‘glue’ cells
A
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
11
Q
What is the most numerous cell in the CNS?
A
Glial cells
12
Q
What is the role of astrocytes? What do they look like?
A
Roles in support, maintain blood-brain barrier, environmental homeostasis
Star shape
13
Q
What is the role of oligodendrocytes? What do they look like?
A
Produce myelin in the CNS
Round nucleus which is stained
14
Q
What is the role of microglia? What do they look like?
A
Immune monitoring and antigen presentation (don’t originate from CNS)
Similar to macrophages
15
Q
What is the role of ependymal? What do they look like?
A
Line ventricles (no barrier to CSF) Square-shaped cells that are 'epithelium like'
16
Q
What three structures give rise to the bumpy surface of the brain?
A
Gyrus (bumps)
Sulcus (grooves)
Fissures (deeper than sulcus)
17
Q
The white matter of the brain contains ___ and is found on the inside/outside of the brain which is the opposite to the spinal cord
A
Axons, glial cells, blood vessels
Inside
18
Q
The grey matter of the brain contains ___ and is found on the inside/outside of the brain which is the opposite to the spinal cord
A
Neurones, cell processes, synapses, glia, blood vessels
Outside
(H pattern in spinal cord)
19
Q
The posterior fibres in the spinal cord are involved in motor/sensory information whereas the anterior fibres convey motor/sensory information
A
Sensory from dorsal (posterior) horn
Motor from the ventral (anterior) horn
20
Q
The precentral gyrus is associated with what type of cortex?
A
Somatosensory
21
Q
The postcentral gyrus is associated with what type of cortex?
A
Somatomotor
22
Q
The lentiform nucleus can be split into…
A
Putamen
Globus pallidus
23
Q
What is the functions of the corpus callosum?
A
Connects both hemispheres of the brain
Connects brain to spinal cord
24
Q
What is the name for the touching part between the thalamus and hypothalamus?
A
Interthalamic adhesion
25
Columns in the spinal cord are composed of ___ matter, whereas horns are composed of ___ matter
White
| Grey
26
Which sulci border the frontal lobe posteriorly and inferiorly respectively?
Central sulcus
| Lateral sulcus
27
Which sulci border the parietal lobe anteriorly, inferiorly and posteriorly respectively?
Central sulcus
Lateral sulcus
Parieto-occipital sulcus (to preoccipital notch)
28
Which sulci border the occipital lobe anteriorly?
Parieto-occipital sulcus
29
Which sulci border the frontal lobe superiorly, inferiorly and medially respectively?
Lateral sulcus
Parieto-occipital sulcus (to preoccipital notch)
Calcarine sulcus (to preoccipital notch)
30
What is known as the fifth or 'hidden' lobe?
Insular lobe or insula
31
What fissure extends down between the cerebral hemispheres splitting the frontal, parietal and occipital lobes?
Longitudinal cerebral fissure
32
What are the layers of the meninges from superficial to deep?
1. Dura
2. Arachnoid matter
(Subarachnoid space)
3. Pia matter
33
Where does CSF drain to?
Subarachnoid space (and some to central canal of spinal cord)
34
Outline the route taken by CSF
Lateral Vs - Interventricular foramen - 3rd V - cerebral aqueduct - 4th V - SA space
35
What is known as the 3rd nervous system? Where is it located? What is it divided into?
Enteric nervous system
In digestive system (Oesophagus - rectum)
2 wall plexuses
1. Myenteric (between SM)
2. Submucosal (submucosa)
36
Outline the blood supply to the brain, splitting it into two systems
INTERNAL CAROTID SYSTEM
Anterior cerebral arteries
Middle cerebral arteries
Internal carotid arteries (form MCA)
VERTEBROBASILAR SYSTEM
Basilar artery
Vertebral arteries
37
What is the Circle of Willis?
An arterial polygon formed as the internal carotid and vertebral systems anastomose around the optic chiasm and infundibulum of the pituitary stalk
38
What territory of the brain is supplied by the ACA, MCA and PCA respectively?
Medial frontal lobe
Lateral frontal lobe, parietal lobe and temporal lobe
Mostly occipital lobe
39
Outline the venous drainage of the brain
Blood drains into intercavernous and cavernous dural venous sinuses, then into jugular foramen and finally the internal jugular vein
40
Where does the spinal cord end?
L1/L2
41
What are the two enlargements of the spinal cord?
Cervical (UL)
| Lumbar (LL)
42
What are the terms used to describe a group of cell bodies outside the CNS vs. inside the CNS?
Ganglion
| Nucleus
43
What is the pathway taken by each segment of the spinal cord?
Rootlets ---> Roots ---> Subarachnoid space ---> Intervertebral foramina ---> Roots fuse to form mixed spinal nerve --> Ramii
44
Posterior root is enlarged by...
Dorsal root ganglion
45
Where does the spinal cord terminate? What does it continue as?
Conus medullaris
| Thin CT cord = Filum terminale
46
Which foramen allows spinal and cranial meninges to be continuous with each other?
Foramen magnum
47
The spinal cord is suspended in the spinal canal by what ligament? What is it formed from?
Denticulate ligament
| Pial and arachnoid tissue
48
What are the 3 components of white matter in the spinal cord?
Posterior, lateral and anterior fasciculi
49
What are the 5 components of grey matter in the spinal cord?
Left and right posterior and anterior horns (arms of 'H')
| Dorsal and ventral grey commisures (join of 'H') which surround central canal
50
What is the arterial supply of the spinal cord and what do they originate from?
Vertebral arteries ---> 1 anterior and 2 posterior longitudinal arteries
Vertebral, intercostal, lumbar arteries ---> Segmental arteries
Various spinal arteries ---> Radicular arteries
51
Where do radicular arteries travel?
Along dorsal and ventral roots
52
What is the venous drainage of the spinal cord?
Similar to supply - longitudinal and segmental veins
53
In the spinal canal, what is the space between dura and bone known as? What is it composed of?
Epidural space
| Adipose tissue and venous plexuses
54
Information from the periphery reaches the cortex in the spinal cord. What parts of the body are an exception to this?
Face and scalp
55
The ascending spinal cord tract is sensory/motor, whereas the descending is sensory/motor
Sensory
| Motor
56
What is the role of the dorsal column/ medial lemniscus system?
SENSORY: Fine touch, vibration and conscious proprioception (mostly upper limb)
57
Where do the fibres from the medial lemniscus system originate, cross and synapse to reach the cortex?
Medial lemniscus!
Medulla
Thalamus
58
What is the role of the spinothalamic tract?
SENSORY: Carries pain, temperature and deep pressure
59
Where do the fibres from the spinothalamic tract originate, cross and synapse to reach the cortex?
Spinal lemniscus (Medulla)
Segmentally in spinal cord
Thalamus
60
What is the role of the corticospinal/pyramidal tract?
MOTOR: fine, precise movement especially of distal limb muscles, for example digits
61
Where do the fibres from the CST start and end?
| Where do the fibres from the corticospinal tract cross?
Cortex and spinal cord (lumbar region)
Medulla at decussation of pyramids (why it is also referred to as pyramidal tract)
NOT ALL OF THEM!
62
The crossed fibres of the CST form what part of the CST?
Lateral
63
The uncrossed fibres of the CST form what part of the CST?
Ventral (cross segmentally)
64
Which spinal tract is involved in decorticate posturing?
Corticospinal tract (FLEXOR - ARMS LIKE C)
65
What is the motor system outside the pyramidal tract known as? What tracts is it composed of?
Extrapyramidal system
| Tectospinal, reticulospinal, vestibulospinal tracts
66
What is the role of the tectospinal tract?
Input to cervical segments - mediate reflex head and neck movement due to visual stimuli e.g. following a moving bus with your eyes
67
What is the role of the reticulospinal tract?
Forms central core of brainstem - receives input from all parts of CNS and influences voluntary movement, breathing and heart rate
68
Where do fibres from the reticulospinal tract originate from?
Reticular formations in the pons and medulla
Pons - extensor movement, inhibits flexor
Medulla - flexor movement, inhibits extensor
69
What is the role of the vestibulospinal tract?
Excitory input to 'antigravity' extensor muscles e.g. stabilise yourself if falling (LATERAL)
Control head movement via neck and back muscles (MEDIAL)
70
Where do fibres from the vestibulospinal tract originate from and where do they receive inputs from?
```
Vestibular nuclei (lateral (Deiters nucleus) and medial) of pons and medulla
CNIII from vestibular labyrinths and cerebellum
```
71
Which spinal tract is involved in decerebrate posturing?
Vestibulospinal tract (EXTENSOR - ARMS LIKE E)
72
Where does the TST start and end?
Optic tectum or superior colliculus (roof of midbrain) and spinal cord (cervical region)
73
Where does the TST recieve inputs from?
Retina, visual cortex and afferents
74
What is the role of the cerebellum?
Involved in planning intended movement in motor cortex and feeding it to the CST for movement to occur
75
What is the basal ganglia? What is their role?
Series of grey matter structures key to initiation and inhibition of movement
Role in posture and muscle tone
76
How is white and grey matter distributed in the cerebellum?
Core of white matter
| Grey matter outside
77
What exists anterosuperiorly, posteriorely and superiorly to the cerebellum respectively?
Cerebral hemispheres
Pons and medulla
Lateral fissure
78
List the lobes that combine to form the cerebellum
Anterior
Posterior
Floccolus ('ear') - part of flocculonodular lobe
79
List the fissures that exist within the cerebellum and give their position
Primary (between anterior and posterior)
| Horizontal (splits posterior)
80
What cavity does the cerebellum exist within? What cavities exists superiorly and posteriorly to this?
Tentorium cerebelli
Falx cerebri
Falx cerebelli
81
How is the cerebellum attached to the brainstem?
Via 3 peduncles - superior, middle and inferior cerebellar peduncles
82
Which is the largest cerebellar peduncle?
Middle
83
What parts of the cerebellum can be attributed to its function?
Vermis (line down middle of A and P lobe)
| Grey matter within the core (series of nuclei that communicate outputs from the cerebellum)
84
What are the 3 layers of the cortex from outside to inside?
Molecular layer
Purkinje cell layer
Granule cell layer
85
Where do afferent inputs to the cerebellum arrive from? (3)
MOTOR
Spinal cord (via somatic proprioceptors and pressure receptors)
Cerebral cortex (via pons)
Vestibular apparatus via nuclei
86
Where in the cerebellum do afferent projections enter and project to?
Cerebellar peduncle
| Granular layer
87
Where does the efferent output from the cerebellum come from? What is the function of this?
Axons of purkinje cells
| Coordinate function of all motor tracts
88
Where do efferent outputs from the cerebellum synapse? What happens after this?
Thalamus
| Sends fibres to motor cortex
89
A lesion to a cerebellar hemisphere would cause symptoms on the ipsilateral side. True/False?
True
90
What symptoms would we expect from a lesion to a unilateral hemisphere?
Coordination problems - intention tremor, unsteady gait
91
What symptoms would we expect from a lesion to bilateral hemispheres?
```
Speech problems (Dysarthria)
Gait problems (Ataxic gait)
```
92
What symptoms would we expect from a lesion to the midline of the cerebellum?
Posture problems - falls over when standing
93
List some basal ganglia
Caudate nucleus
Putamen and globus pallidus (lentiform nucleus)
Subthalamic nucleus
Substantia nigra
94
What is the striatum of the basal ganglia?
Caudate nucleus
| Putamen
95
What is the corpus striatum?
Caudate nucleus
Putamen
Globus pallidus
96
What does the lentiform nucleus look like?
```
Globus pallidus (two stripes)
Putamen (lentil)
```
97
What does the caudate nuclei look like?
Horn
98
What is located lateral and medial to the internal capsule (white matter tract)?
Lentiform nucleus
| Thalamic nuclei
99
What does the substantia nigra look like? Where is it located in the brainstem?
Black lines
| Midbrain
100
What disease is characterised by degeneration of dopaminergic neurones of substantia nigra?
Parkinsons Disease
101
What pathway is used to enhance normal movement by the basal ganglia?
Direct pathway
| Enhance outflow of thalamus
102
What pathway is used to inhibit unwanted movement by the basal ganglia?
Indirect pathway
| Inhibit outflow of thalamus
103
Unilateral lesions of the basal ganglia affect the ipsilateral side. True/ False?
False
| Affect contralateral side
104
What symptoms would we expect from a lesion to the basal ganglia?
Change in muscle tone
Dyskinesias (abnormal involuntary movement) inc. tremor, chorea (rapid asymmetrical movements typically by the distal limbs), myoclonus (muscle jerks)
105
What symptoms would we expect in Parkinsons Disease?
REDUCED OUTPUT TO CORTEX
Akinesia (impairment of the power of voluntary movement)
Rigidity
Resting tremor
106
What is Huntingdon's Disease?
Progressive degeneration of basal ganglia and cerebral cortex
107
What symptoms would we expect in Huntingdon's Disease?
Chorea
| Progressive dementia
108
Which CN has functions outwith the head?
Vagus nerve
109
What is a cranial nerve associated with in the brain?
Association with streak of grey matter in the brain/ brainstem with one function
110
Which direction do most cranial nerves exit the brain? What are the exceptions?
Anteriorly
CN IV - posteriorly
CN VIII - laterally
111
Soma of sensory nerve cells are found within the CNS. True/ False?
False
| In ganglia outside the CNS
112
Which CN is the only sensory modality that does not synpase in the thalamus before reaching the cortex?
Olfactory nerve
113
Which CNs have a nuclei of origin close to the midline?
CN III, IV, VI, (XII - closeish)
114
What is the modality and function of the olfactory nerve?
Sensory
| Smell
115
What is the modalities and functions of the oculomotor nerve?
Somatic motor - levator ps., SR, MR, IR, IO
| Parasympathetic - sphincter pupillae ciliary muscle
116
What is the ciliary ganglion controlled by?
Edinger westphal nucleus
117
What is the modality and function of the trochlear nerve?
Somatic motor - SO
118
What is the modality and function of the abducens nerve?
Somatic motor - LR
119
What is the modality and function of the hypoglossal nerve?
Somatic motor - geniog, hyog, stylog, intrinsic tongie muscles
120
Where does the spinal accessory nerve arrive from?
Cervical spinal cord
121
What are the 3 functions of the trigeminal nerve and the 4 nuclei associated with it?
1. Somatosensation of face with oral sparing (discriminative touch, vibration - PONTINE TRIGEMINAL NUCLEUS)
(pain, temperature - SPINAL NUCLEUS)
2. Proprioception associated chewing (TMJ, muscles of mastication, teeth) - MESENCEPHALIC NUCLEUS
3. Motor control (muscles of mastication, tensor tympani, mylohyoid, A belly of digastric, tensor veli palatini) - MOTOR NUCLEUS
122
What are the trigeminal sensory nuclei?
Mesencephalic nucleus
Pontine trigeminal nucleus (PRINCIPAL)
Spinal nucleus
123
Where does the trigeminal sensory nucleus start and finish?
Midbrain
| Cervical spinal cord
124
What is the only site in the CNS where cell bodies of primary afferent neurones live inside the CNS?
Mesencephalic nucleus
125
Why do we get bilateral representation of touch, vibration etc. in the cortex from the trigeminal nerve?
Most fibres of the ventral trigeminothalamic tract cross in the midline but some don't
126
What are the 3 functions of the facial nerve and what 3 nuclei are associated with each?
1. Motor supply to muscles of facial expression, stapedius - FACIAL MOTOR NUCLEUS
2. Parasympathetic to pterygopalatine and submandibular ganglia - SALIVATORY NUCLEUS
3. Taste to the A 2/3s of the tongue via chorda tympani - SOLITATORY NUCLEUS
127
What are the 4 functions of the glossopharyngeal nerve and what 3 nuclei are associated with each?
1. Tactile sense, pain, temperature from P tongue and upper pharynx - SPINAL TRIGEMINAL NUCLEUS (small area of ear)
2. Taste to P 1/3 of tongue - SOLITATORY NUCLEUS
3. PS to otic ganglion (parotid gland) - SALVATORY NUCLEUS
4. Motor supply to stylopharyngeus - NUCLEUS AMBIGUUS
128
What are the 4 functions of the vagus nerve and what 4 nuclei are associated with each?
1. Tactile sense, pain, temperature from pharynx to abdomen - SPINAL TRIGEMINAL NUCLEUS
2. Taste (epiglottis) - SOLITATORY NUCLEUS
3. PS to ganglia serving thoracic and abdominal viscera - DORSAL (MOTOR) NUCLEUS
4. Motor to muscles of pharynx and larynx (+ CN XI) - NUCLEUS AMBIGUUS
129
What CNs are supplied by the solitatory nucleus?
VII, IX, X
130
What CNs are supplied by the salvatory nucleus?
VII, IX
131
What CNs are supplied by nucleus ambiguus?
IX, X and cranial part of XI
132
List the areas of taste attributed to the solitary nucleus on the tongue and their sensory CN supply from front-back
```
A 2/3 - VII
P 1/3 - IX
Epiglottis - X
Carotid sinus/ body - IX
Aortic arch and viscera (pulmonary stretch receptors) - X
```
133
What tract provides the motor input to CN V, VII, X, XII
CST
134
What supplies input to PS efferents of CN III, VII, IX, X?
Hypothalamus directly and via reticular formation
135
What is reticular formation?
Network of loosely aggravated cells with cell bodies, axons and dendrites in the central core of the brainstem
136
What are the functions of the reticular formation?
Integrate CN reflexes
Conduct and modulate pain
Voluntary movement
Regulate autonomic activity
Integrate basic functions - respiration, SLEEP
Activate cerebral cortex (component of ARAS)
137
Which CN is involved in hearing?
CN VIII - Cochlear nerve
138
What route is taken by the cochlear nerve to reach the thalamus?
```
ECOLI
Cochlear nerve (EIGHTH CN) -->
Cochlear nucleus (C) -->
Superior olivary nucleus (O)-->
(LATERAL LEMNISCUS)
Inferior collicus (I) -->
Medial geniculate body (in thalamus)
```
139
A unilateral hearing problem is typically an issue with the cochlea. True/ False?
False
Typically, a brainstem issue
Superior to cochlear nuclei, some fibres are crossed and some are not = bilateral input
140
What are the auditory ossicles of the middle ear?
Malleus, incus and stapes
141
What is contained within the organ of corti in the cochlea?
Inner and outer hair cells
142
What is the role of the spiral ganglion within the cochlea?
Bipolar neurones that are stimulated by hair cells and carry action potentials from organ of corti to cochlear nuclei in pons
143
Where is the primary auditory cortex in the brain - in terms of lobes and fissures?
Temporal lobe
| Close to lateral fissure
144
What area of the auditory cortex do low frequency fibres end, versus high frequency fibres?
Anterolateral
| Posteromedial
145
What is the function of the superior olivary nucleus and lateral lemniscus in hearing?
Sound localization and relays info for stapedial and tensor tympani reflexes
146
What is aphasia? Which side of the brain is dominant for language?
Inability to use language
| Left predominantly
147
What would we expect to happen if there was damage to Broca's area? Where is Broca's area?
MOTOR/ EXPRESSIVE APHASIA
Difficulty in producing language - typically few words/ most important ('broken')
Frontal lobe
148
What would we expect to happen if there was damage to Wernicke's area? Where is Wernicke's area?
SENSORY/ RECEPTIVE APHASIA
Difficulty comprehending language - words out of order/ meaningless words
Temporal lobe
149
Which CN is involved in balance?
CNVIII - vestibular nerve
150
Which part of the inner ear is involved in balance?
3 semicircular canals
151
What are the main connections of vestibular nuclei?
Thalamus
Nuclei of CN III, IV, VI (Eye control)
Cerebellum (flocculonodular lobe)
Spinal cord
152
There is no 'vestibular cortex', where does the projection of vestibular information typically converge?
Parietal cortex/ posterior to postcentral gyrus that represents hand and mouth)
Anterior to primary auditory cortex
Posterior insular cortex
153
What part of the thalamus is involved in processing visual information?
Lateral geniculate nucleus
154
Each optic tract, LGN, optic radiation and visual cortex deals with visual information from the contralateral/unilateral field.
Contralateral
155
What is the role of the superior cocculi in vision?
Recieve inputs and outputs to nuclei of CN III, IV, VI and motor nucleus of VII and spinal cord
Mostly involved in 'automatic vision'
156
Where is the primary visual cortex located in the brain - in terms of lobes and fissures?
Occipital lobe
| Above and below the calcarine sulcus
157
Which visual field is projected to gyrus superior to the calcarine sulcus?
Lower visual field
| Upper projects to inferior
158
Which pole of the cortex does the macula project to?
Posterior pole (occupies large proportion)
159
What is Meyer's loop?
Fibres of geniculocalcarine tract that form part of the internal capsule
Visual information from upper half of field first loop anteriorly around temporal part of lateral ventricle
160
What type of eye movement is the visual cortex involved in?
Movements in response to visual stimuli (tracking moving objects) - SMOOTH
161
What type of eye movement is the frontal eye fields involved in?
Movements of command (no moving visual stimuli) - JUMPY
162
In the consensual light reflex, what is the mechanism behind the constriction of the contralateral pupil?
Pretectal fibres project bilaterally to EW nucleus
163
In the accommodation reflex, what receives inputs from the visual cortex?
Oculomotor nerve
| EW nucleus
164
What is meant by the term 'cortical localization'?
Some higher functions are greater in one cerebral hemisphere - this is the dominant hemisphere
165
What are the 3 types of white matter tracts in the brain?
Association fibres - connect cortical sites lying in same hemisphere
Commissural fibres - connect one hemisphere to other
Projection fibres - connect hemispheres to deeper structures including thalamus, corpus striatum, brain stem and spinal cord
166
Which part of a myelinated axons allows the spread of saltatory conduction?
Node of Ranvier
167
What is the route for sympathetic nerve supply to the eye?
```
T1 sympathetic trunk ganglion --->
Superior cervical sympathetic ganglion --->
Internal carotid plexus --->
Ciliary ganglion --->
Short ciliary nerve
```
168
Where does the lateral and medial VST terminate, respectively?
Lumbar spinal cord
| Cervical spinal cord
169
Where do axons of the TST deccusate?
Dorsal tegmental decussation in the brainstem
170
What is the function of the rubrospinal tract, and where do the fibres originate?
Extra-pyramidal tract that excites flexors and inhibitis extensors of UL
Red nucleus in midbrain
171
What is the function of the spinocerebellar tract?
SENSORY
| Transmits unconscious proprioceptive information for posture and movement
172
The DCML pathway divided into what two divisions after synapsing?
>T6: Nucleus cuneatus
| < T6: Nucleus gracillus
173
What is the function of the limbic system?
Encircles corpus callosum and is involved in higher emotional functions and memory
174
The afferent limb of the pupillary light reflex is controlled by which cranial nerve?
CNII
175
The efferent limb of the pupillary light reflex is controlled by which cranial nerve?
CNIII (thrEEE)
176
Outline the somatotopic layout of the corticopsinal tract, in terms of anatomical location controlled, at the spinal cord
```
Medial = UL
Lateral = LL
```
177
Which artery does CNIII travel close too, once exiting the midbrain, and can damage CNIII if there is an aneurysm?
Posterior communicating artery
