Gross Brain, Brain Stem, And Spinal Cord Flashcards
1
Q
What are the cranial meninges?
What do they do?
A
3 dense regular CT layers
Separate soft tissue of brain from bones of cranium
2
Q
Functions of Cranial Meninges (3)?
A
‣ Enclose and protect blood vessels that supply the brain
‣ contain and circulate cerebrospinal fluid
‣ Form some of the veins that drain blood from the brain
3
Q
What are the layers of the cranial meninges from superficial to deep?
A
‣ Dura Mater
‣ Arachnoid Mater
‣ Pia Mater
4
Q
What is the composition of
Dura mater?
A
‣ Tough membrane composed of 2 fibrous layers
‣ Strongest
5
Q
What are the layers of the dura mater?
A
- Periosteal layer: more superficial layer, attaches to the periosteum of the cranial bones
- Meningeal layer: deep to the periosteal layer
‣ meningeal layer fuses to periosteal
6
Q
What can the 2 layers of Dura Mater form?
A
dural venous sinuses
When meningeal and periosteal layer become separated
7
Q
What is an epidural hematoma from?
How will it appear on a CT?
A
Ruptured middle meningeal a.
Will look like a “lens” on a CT
8
Q
What is the composition of the arachnoid layer?
A
‣ Composed of web of collagen and elastic fibers = arachnoid trabeculae
9
Q
What is between the arachnoid and dura mater layers?
When is this formed?
A
Potential space - Subdural space
Only occurs when an accel/deacell. Event has happened and caused a bleeding from a bridging v.
10
Q
How does a Subdural hematoma appear on a CT?
A
Crescent shaped
11
Q
What space is found deep to the arachnoid layer of meninges?
What is found in here?
A
Subarachnoid space
CSF
12
Q
How does a subarachnoid hemorrhage occur?
How does it appear on a CT?
A
Hemorrhage from cerebral artery; berry aneurysm
Spiderweb
13
Q
What is the pia mater?
A
Innermost meninges
Adheres to brain and follow contour of brain
14
Q
What are the 12 CNs?
A
- Olfactory
- Optic
- Oculomotor
- Trochlear
- Trigeminal
- Abducens
- Facial
- Vestibulocochlear
- Glossopharyngeal
- Vagus
- Spinal accessory n.
- Hypoglossal
15
Q
What brainstem nuclei give rise to the modalities in
CN 3?
A
GSE - nucleus f oculomotor n. In mesencephalon
GVE - edinger-westphal nucleus (paras.)
16
Q
What brainstem nuclei give rise to the modalities in
CN 4?
A
GSE - Nucleus of Trochlear N. In Mesencephalon
17
Q
What brainstem nuclei give rise to the modalities in
CN 5?
A
GSE: motor nucleus of trigeminal n.
SVE: Principal sensory nucleus of CN 5;
Mesencephalic Nucleus of Trigeminal n.; Spinal Nucl. Of Trigeminal N.
18
Q
What brainstem nuclei give rise to the modalities in
CN 6?
A
GSE: Nucleus of Abducens N.
19
Q
What brainstem nuclei give rise to the modalities in
CN 7?
A
GSA: Rostral Nucleus, cadual nucleus?
GVE: Superior salivatory nucleus
SVA: solitary tract nucleus
SVE: Nucleus of Facial N. (In lower part of pontine tegmentum)
20
Q
What is the floor of the fourth ventricle divided into?
What divides them?
A
Medial part = basal lamina
Lateral part = alar lamina
Sulcus limitans
21
Q
What nuclei lie in the basal lamina?
A
Motor nuclei (efferent)
22
Q
What nuclei lie in the alar lamina?
A
Sensory nuclei (afferent nuclei)
23
Q
Where does visceral nuclei lie in the alar and basal lamina?
A
In both:
Visceral nuclei (SVE, GVE, SVA, GVA) lie closer to sulcus limitans than somatic nuclei
24
Q
What is the sequence of the nuclear column from midline to lateral?
What lamina of the floor of the 4th ventricle are they in?
A
From median sulcus of 4th entirely to lateral aspect
GSE —> SVE—> GVE
(GSE closest to median sulcus)
(GVE is farther from median sulcus but next to sulcus limitans)
Basal lamina (medial pat)
25
What is the sequence of nuclei on the alar lamina?
On other side of sulcus limitans..
GVA—> SVA—> GSA—> SSA
(SSA is farthest from sulcus limitans laterally)
26
Where does the CN 1 originate from?
Olfactory bulb
27
Where is the olfactory bulb? What does it control?
Forebrain
Controls olfaction
28
Where does CN 2 originate from?
Where does it transmit to?
Retina
Transmits visual impulses to visual cortex (occipital lobe)
29
What nuclei make up the GSE column?
3, 4, 6, 11, 12
Oculomotor nucleus
Trochlear nucleus
Abducens nucleus
Hypoglossal nucleus
30
What nuclei make up the SVE column?
5, 7, 9, 10
Motor nucleus of Trigeminal N. (Pons)
Nucleus of facial N.
(Pontine tegmentum)
Nucleus ambiguus
(Medulla)
(9, 10, and 11 receive fibers from this)
31
What nuclei make up the GVE column?
What do they give origin to?
Give origin to preganglionic fibers
3, 7, 9, 10
Edinger-westphal nucleus (midbrain)
Superior and inferior Salivatory Nuclei (dorsal part of pons)
Dorsal vagal nucleus (Vertical in medulla)
32
What nuclei make up the GVA and SVA columns?
GVA: 9, 10
SVA: 1, 7, 9, 10
Nucleus of solitary tract (medulla) (9 and 10)
Commissural nucleus of vagus (10)
Gustatory nucleus (in upper part of solitary tract, for SVA [taste] for 7, 9, 10)
33
How does the commissural nucleus of the vagus nerve form?
Fibers from solitary tract end here and fuse together
34
What nuclei make up the GSA column?
GSA: 5, 7, 9, 10
Principle sensory nucleus of the trigeminal n. (Pons)
-for proprioceptive impulses, touch and pressure
Spinal nucleus of Trigeminal N.
(Extends from main nucleus in pons down to medulla, continuous with substantia of spinal cord)
-receives GSA from 7, 9, 10; mediates pain and thermal sensibility
Mesencephalic Nucleus of Trigeminal N.
(Main nucleus in pons to midbrain)
-center for jaw jerk, proprioceptive impulses from Ms. of mastication
35
What nuclei make up the SSA column?
2, 8
2 cochlear nuclei
- dorsal and ventral nucleus
(At level of pontine medullary junction)
Vestibular nucleus
(Partly in medulla partly in pons)
36
What are the 3 sub-nuclei of the spinal nucleus?
Oralis
Interpolaris
Caudalis
37
What are the 4 nuclei of the vestibular nucleus?
Medial
Lateral (aka Deiter’s nucleus)
Inferior
Superior vestibular nuclei
38
Where does the nucelus of the solitary tract mainly send fibers to?
Where does it receive fibers from?
From: 7, 9, 10
Send to: hypothalamus, thalamus, cerebral cortex
39
What does the PNS consist of?
Collection of spinal and cranial Ns. Whose branches convey messages to and from the CNS
40
What does the CNS consist of?
Brain and spinal cord?
41
What is the brain composed of?
Forebrain
Cerebellum
Brain stem
42
What composes the forebrain?
Cerebral hemispheres
| Diencephalon
43
Where is the brainstem?
Between forebrain and spinal cord
44
What is “Grey matter”?
Areas w/ neuronal/glial cell bodies and dendrites
45
What is “White matter” ?
Areas where there is a collection of axons, many myelinated
46
What is a nuclei?
Collections of cell bodies w/ common function
47
What is a “cortex”?
What are examples?
Layers of grey matter over other parts of CNS
Cerebral and cerebellum vortices
48
What are other terms for white matter?
Fascicles, funiculars, lemniscus, peduncle, tract
49
What are the 2 parts to the name of a tract?
1st: location of neuronal cell bodies from which axons originate
2nd: site of axon termination
50
What does central white matter consist of?
```
Arcuate fibers
Longitudinal/Association fasciculi
Projection tracts
Corpus callosum
Anterior commissure
```
51
What do arcuate fibers do?
Connect cortical areas within
SAME sulci/gyri
52
What do longitudinal/association fasciculi do?
Connect cortical areas within
SAME Hemisphere
53
What do projection tracts do?
Connect cortical areas within
OTHER Body Regions
54
What does the corpus callosum do?
How many axons does it contain?
Interconnects 2 cerebral hemispheres
~250 million axons
55
What does the anterior commissure do?
Commissural fibers to and from temporal lobe
| Esp. Inferior parts
56
What is a gyrus?
Ridge of cortical tissue
57
What is a sulcus? Fissure?
Groove located b/w gyri
Fissure = deep sulci
58
What does the folding seen in brain do?
Increase total cortical area and total number of cortical neurons
59
What are the 4 prominent sulci?
Central sulcus
Lateral sulcus
Parietooccipital sulcus
Cingulate sulcus
60
What is the limbic lobe?
Strip of cortex that encircles telencephalon-diencephalon junction
(Between corpus callosum, and F, P, and O lobes)
61
What does the frontal lobe contain generally?
Motor areas
62
What are the gyri in the
Frontal lobe?
Precentral
| Superior/middle/inferior frontal gyri
On lateral surface
63
What does the precentral gyrus house?
Primary motor cortex
64
What are the function of the primary motor cortex?
Where do you find this cortex?
In precentral gyrus
Planning and initiating voluntary movements
65
What lobe is broca’s area in?
What does it do?
Left Frontal lobe
Motor aspects (Production) of written and spoken language
66
What gyrus is Broca’s area in?
Opercular and triangular parts of inferior frontal gyrus
67
Where is the prefrontal cortex?
Function?
Frontal lobe
Executive functions - personality,d excision making, insight and foresight
68
What does the parietal lobe contain generally?
What gyri doe it have?
Somatosensory areas
Post-central gyrus
Superior/inferior parietal lobules
69
What is the function of the post central gyrus?
What lobe do you find it in?
Primary somatosensory cortex to process tactile and proprioceptive info and sensory localization
Parietal lobe
70
What does the inferior parietal lobule do?
Where do you find this?
Language comprehension
Usually left hemisphere
71
What other functions does the parietal lobe assist in that is not tactile, propioceptive, sensory, or language comprehension?
Not assoc. w/ any structure
Remain does spatial orientation and directing attention
72
What is a Homonculus?
Somatotopic map that is spatially distorted along central sulcus (post central gyri)
Reflects amt. of innervation to a given body area
73
Where is genitalia on a homunculus map?
Most medial
74
Where are toes for the motor cortex of homunculus map?
Most medial
75
What is most inferior along precentral gyri on homunculus?
Motor to Tongue then swallowing
76
What is most inferior along the post central gyri for homunculus?
Somatosensory to pharynx and intra-abdominal
77
What is generally contained in the temporal lobe?
Auditory areas
78
What are the gyri found in the temporal lobe?
Superior
Middle
Inferior temporal gyri
Occipitotemproal gyrus (fusiform)
79
What are the 4 functions of the temporal lobe?
1. Primary auditory cortex
2. Wernicke’s area
3. High order processing of visual info
4. Learning and memory
80
Where is the primary auditory cortex specifically?
Superior surface of temporal lobe
Continues as small are of superior temporal gyrus
81
Where is wernicke’s area specifically?
What does it do?
Posterior portion of superior temporal gyrus (left hemisphere) of temporal lobe
Comprehension of lingual
(Supramarginal and angular gyri also)
May also be a bit in parietal
82
Where does higher order processing of visual info in the temporal lobe occur?
Inferior surface
83
Where does learning and memory in the temporal lobe occur?
Most medial part
84
What are the gyri in Limbic lobe?
Cingulate gyrus
Parahippocampal gyrus
85
What are the 3 structures found in the limbic lobe?
Uncus
Hippocampus
Amygdala
86
Where is the uncus in the limbic lobe?
Anterior end of parahippocampal Grus that hooks back on itself to form medial bump
87
Where is the hippocampus in limbic lobe?
At hippocampal sulcus, folding into temporal lobe
88
Where is the amygdala in the Limbic lobe?
Beneath the uncus
89
What are the functions of the Limbic lobe?
Important in emotional responses, drive-related behavior, memory
90
What is the insula?
Additional area of cerebral cortex
91
Where is the Insula found?
Buried in the lateral sulcus
| Concealed with portions of frontal, parietal, and temporal lobes
92
When can you see the insula?
Pry open the lateral sulcus and remove opercula
93
What is the opercula?
Portion of temporal, frontal or parietal lobes that cover insula
94
What outlines the insula?
What does it do?
Circular sulcus
Marks borders w/ the opercular areas of cortex
95
What are the gyri found in occipital lobe?
Lateral occipital gyri found on lateral surface
96
What 3 structures does the occipital lobe contain?
Cuneus
Primary visual cortex
Visual association cortex
97
What is the Cuneus of the Occipital lobe?
Wedge shaped area bounded w/ parietooccipital and calcarine sulci
98
Where is the primary visual cortex?
In the walls of the calcarine sulcus
99
Where is the visual association cortex?
| What is its function?
Remainder of occipital lobe (not already taken by cuneus or primary visual cortex)
Involved in higher order processing of visual info
100
What is the internal capsule?
White matter structure divided into limbs, each with specific fiber groups
101
What does the internal capsule contain? And what does it do?
Most of the fibers interconnecting cerebral cortex and deep structures of thalamus
Basal nuclei
Brainstem
102
What does the internal capsule physically separate?
Physically separates lenticular nuclei from thalamus and caudate
103
What limbs is the internal capsule divided into?
```
Anterior limb
Genu
Posterior limb
Sublenticular limb
Retrolenticular limb
```
104
What is the basal nuclei?
Caudate and lenticular nuclei that lies deep to cerebral cortex in each hemisphere
105
What is the lenticular nucleus divided into?
Putamen and Globus Pallidus
106
What separates the lenticular nuclei from the thalamus and the caudate?
Thick sheet of fibers ==
The Internal Capsule
107
What is included in the diencephalon?
Thalamus
Hypothalamus
Epithalamus
Subthalamus
108
Where are mammillary bodies located?
Two rounded protuberance on the inferior surface of hypothalamus
109
What is the role of the brain stem?
Major role in cranial nerve functions and convey info to and from forebrain
110
What is in the brain stem?
Midbrain
Pons
Medulla
111
What are the major structures in hte midbrain?
Tectum
Superior and inferior colliculi
Cerebral peduncles
112
Where are the Quadgeminal colliculi located?
Paired superior and inferior colliculi behind cerebral aqueduct
113
What are the structures of the
Pons
Basal pons
| Pontine tegmentum
114
What does the pontine tegmentum assist in?
Forming part of floor of 4th ventricle
115
What does the open rostral part of the medulla contain?
Part of 4th ventricle
116
What is the caudal closed part of the medulla continuous with?
Spinal cord
117
What is the function of the cerebellum?
Sensory info processing
Influences motor neurons
118
What does damage to the cerebellum cause?
Abnormalities of
Equilibrium
Postural control
Coordination of voluntary movements
119
What are the transverse ridges present on the cerebellum?
Folia
120
What is the cerebellum divided into?
Lobes and lobules
121
Where is white matter in the cerebellum?
Medullary center
Both afferent and efferent fibers
122
Which CN exit SOF?
3, 4, v1, 6
123
What CNs exit the internal acoustic meatus?
CNs 7 and 8
124
What CNs exit the jugular foramen?
9, 10, 11
125
Where does the spinal component of CN 11 exit?
Foramen magnum
126
What is the arterial supply to the internal capsule?
Mostly fed by lenticular striae arteries
| Except anterior choroidal artiers that feed posterior and retrolenticular limbs
127
What does the insula function in?
Taste
128
What is the function of the parahippocampus and Hippocampus?
Learning and Memory
129
What is the function of the amygdala?
Fear and emotion
130
How do posterior rootlets enter the spinal cord?
Via posterolateral sulcus
| Shallow longitudinal groove
131
How do anterior roots leave the SC?
Via anterolateral sulcus
132
What and where is the substantia gelatinosa?
Posterior horn of SC
Region of grey matter that caps posterior horn
133
What is contained in the body of the posterior horn?
Interneurons and projection neurons that transmit somatic adn visceral SENSORY info
134
Where and what is Lissauer’s tract?
Posterior horn
White matter b/w substantia gelatinosa and surface of SC
135
Where and what is Clark’s nucleus?
| Aka Posterior thoracic nucleus
Cells on medial surface of the base of the posterior horn from T1 to L2
Role in sensory processing
Treated as part of the posterior horn
136
Where is White matter and grey matter in the spinal cord?
Outside: white
Inside: grey
137
Where is white and grey matter in the brain?
White: inside
Grey: outside
138
What is in the anterior horn of the SC?
Cell bodies of motor neurons supplying skeletal muscles
139
What is role of anterior horn?
Provide cns control over body movements (both vol. and involuntary.)
140
WHat is the anterior horn influenced by to modulate movements?
Different pathways
141
What is the intermediate gray matter seen in SC?
Collection of various projection neurons, sensory interneurons, and interneurons
142
What forms the lateral horn?
Preganglionic sympathetic neurons from T1-L3 in the intermediolateral cell column
Will only see it in thoracic!!
143
How do axons leave the lateral horn?
Via ventral roots?
144
Does the parasympathetic nucleus form a distinct horn from S2-S4?
No
145
Of the spinal cord gray matter, what is
Lamina 1?
Marginal zone
Thin layer of gray matter covering the substantia gelatinosa
146
Of the spinal cord gray matter, what is
Lamina 2?
Substantia gelatinosa
147
Of the spinal cord gray matter, what is
Lamina 3-6?
Body of the posterior horn
148
Of the spinal cord gray matter, what is
Lamina 7?
Corresponds to intermediate gray matter (incl. Clarke’s nucleus)
Also includes extensions into anterior horn
149
Of the spinal cord gray matter, what is
Lamina 8?
Comprises some of the interneurons zones of the Anterior Horn
150
Of the spinal cord gray matter, what is
Lamina 9?
Consists of clusters of Motor Neurons embedded in the Anterior horn
151
Of the spinal cord gray matter, what is
Lamina 10?
Zone of gray matter surrounding the central canal
152
Marginal Zone Nucleus:
Levels?
Lamina?
Function?
All levels
Lamina 1
Some Spinothalamic tract cell
153
Substantia Gelatinosa
Levels?
Lamina?
Function?
All levels
Lamina 2
Modulate transmission of pain and temperature information
154
Body of posterior horn nucleus:
Levels?
Lamina?
Function?
All levels
Lamina 3-6
Sensory processing
155
Clarke’s nucleus:
Levels?
Lamina?
Function?
T1-L2
Lamina 7
Posterior spinocerebellar tract cells
156
Interomediolateral column nucleus :
Levels?
Lamina?
Function?
T1-L3
Lamina 7
Preganglionic sympathetic neurons
157
Sacral parasympathetic nucleus:
Levels?
Lamina?
Function?
S2-S4
Lamina 7
Preganglionic parasympathetic neurons —> pelvic viscera
158
Accessory Nucleus:
Levels?
Lamina?
Function?
Medulla -C5
Lamina 9
Motor Neurons —> SCM and Traps
159
Phrenic nucelus:
Levels?
Lamina?
Function?
C3-C5
Lamina 9
Motor neurons —> diaphragm
160
What conveys info to/from the CNS?
Primary afferents = to
Lower motor neurons = from
161
Where do primary afferents terminate in the CNS?
Contralateral or ipsilateral?
On second order neurons
Most are IPSILATERAL
162
Where do Lower motor Nuerons convey info to?
To skeletal msucle
163
Where do the second order neurons go from the CNS after being activated by primary afferent?
To a target in the CNS
Can cross the midline
164
What do third order neurons do?
Relay the message to the final target in specific cortical area
Cortex will decide on given output
165
How are tracts named?
According to
Location of cell body of origin
&
Final destination
166
What are 3 ascending tracts?
Posterior columns
Spinocerebellar tracts
Anterolateral system (ALS)
167
What is the function of the posterior column?
Ascending or descending ?
Ascending
Conveys ipsilateral proprioceptive, tactile, and vibratory info from body (NOT FACE)
168
What is the function of the spinocerebellar tracts?
Ascending or descending ?
Ascending
Info relays to cerebellum, thalamus, and motor cortex to influence efficiency of motor activity
(Postural and motor control)
169
What is the function of the anterolateral system?
Ascending or descending ?
Ascending
Relays pain, temp, and nondiscriminative touch from body (NOT Face)
170
What are 3 descending tracts?
Corticospinal tract
Vestibulospinal tract
Rubrospinal fibers
171
What is the function of the corticospinal tract?
Ascending or descending ?
Descending
Controls voluntary, fine movements of the musculature
172
What is the function of the vestibulospinal tract?
Ascending or descending ?
Descending
Influence motor neurons innervation go primarily axial and neck musculature
173
What is the function of the rubrospinal fibers?
Ascending or descending ?
Descending
Excite Flexor motor neurons
Inhibit Extensor motor neurons
(At neck)
174
Where does the posterior column MEdial Lemniscus pathway cross?
What is it for?
In caudal medulla (brainstem)
Touch/propioception
175
Where does the Spinothalamic pathway cross?
What is it for?
Immediately goes into SC and crosses
Pain/temperature
176
Where does the corticospinal pathway cross?
What is it for?
Crosses at Medulla
Voluntary motor output
177
Where is wernicke’s area?
Posterior portion of superior temporal gyrus
And supramarginal and angular gyri too
178
What does wernicke’s area do?
Comprehension of language
