The Brain and Spinal Cord Flashcards
(171 cards)
1
Q
What does the central nervous system encompass?
A
- Brain
- Spinal Cord
- Cavities (immersed in cerebrospinal fluid)
- Nerves
2
Q
What cavity is the brain located in?
A
The cranial cavity
3
Q
The cranial cavity is a subdivision of?
A
The dorsal cavity
4
Q
How much does the brain weigh?
A
3 lbs
5
Q
What is the protective coverings over the brain?
A
Meninges
6
Q
What is the brain surrounded by?
A
Cerebrospinal fluid that cushions and provides buoyancy.
7
Q
What is the brain/nerve network responsible for?
A
Transmitting electrochemical messages in the body
8
Q
The brain contains regions of what?
A
White and grey matter
9
Q
What are the 3 main regions of the brain?
A
1) Cerebrum
2) Cerebellum
3) Brainstem
10
Q
What is white matter?
A
Brain tissue composed of nerve axons that are covered with myelin.
11
Q
What is myelin?
A
Fatty tissue that helps conduction of nerve impulses (gives white matter it’s “white” appearance.
12
Q
What do axons do?
A
Carry the nerve impulses between neurons
13
Q
What is grey matter?
A
Composed of nerve cell bodies, which are unmyelinated
14
Q
What are the nerve cell bodies?
A
Control centres that route sensory and motor stimuli and create a response.
15
Q
What is the largest part of the brain?
A
The cerebrum
16
Q
How is the cerebrum divided?
A
Left and right hemispheres
17
Q
How are the right and left hemispheres connected?
A
In the midline by the corpus callosum
18
Q
What separates the right and left hemispheres?
A
The falx cerebri
19
Q
How are the left and right hemispheres divided?
A
Each hemisphere divides into 4 lobes.
20
Q
What type of matter is the cerebrum?
A
Both white and grey
21
Q
What is the grey matter of the cerebrum?
A
- Outer layer of the cortex
- The basal nuclei (deep in midline)
22
Q
What is the white matter of the cerebrum?
A
Lies deep in the cortex
23
Q
What are the 4 lobes of the cerebral hemispheres?
A
1) Frontal lobe
2) Parietal lobe
3) Occipital lobe
4) Temporal lobe
24
Q
What do the 4 lobes correspond to?
A
Their adjacent cranial bone
25
How does the cerebrum appear?
Lots of folds and grooves
26
What are the small folds in the cerebrum called?
Gyri
27
What are the shallow grooves in the cerebrum called?
Sulci
28
What are the deep grooves in the cerebrum called?
Fissures
29
What are the fissures in the cerebrum?
1) Longitudinal
| 2) Lateral
30
What is another name for the lateral fissure in the cerebrum?
Sylvian
31
What is the corpus callosum?
A bundle of white matter located in the midline
32
What is the function of the corpus callosum?
It is a neural bridge (connection) between the left and right hemispheres.
33
What forms the roof of the lateral ventricles?
The corpus callosum
34
How is the corpus callosum divided and what are the divisions?
4 Parts:
1) Rostrum
2) Genu
3) Body
4) Splenium
35
What is another name for the basal nuclei?
Ganglia
36
What is the basal nuclei?
Distinct regions of grey matter deep within the cerebral white matter.
37
What is the purpose of the basal nuclei?
Serve as relay stations for sensory stimuli
38
What do the basal nuclei lie adjacent to?
The lateral ventricles
39
What does the basal nuclei include?
1) The caudate nucleus
| 2) Lentiform nucleus
40
What part of the basal nuclei has multiple parts and what are they?
The lentiform nucleus includes the Putamen and the Globus Pallidus
41
What is the thalamus?
Two oval masses of grey matter that serve as relay stations for nerve impulses
42
Where is the thalamus located?
At the base of the cerebral hemispheres on either side of the third ventricle.
43
What do the thalami form? **
Lateral walls of the third ventricle
44
What is the massa intermedia?
A tissue bridge between the right and left thalami that passes through the third ventricle in the midline
45
What are the functions of the brainstem?
1) Connects brain to spinal cord
| 2) Controls vital functions (Breathing, heart rate)
46
What are the parts of the brainstem?
1) Midbrain
2) Pons
3) Medulla Oblongata
47
What is the superior and smallest part of the brainstem?
The midbrain
48
What is directly inferior to the midbrain?
The pons
49
What does the midbrain surround?
The cerebral aquaduct
50
What is the pons?
A prominent anterior bulge
51
Where is the pons located?
Between the midbrain and the medulla oblongata
52
What are the functions of the pons?
1) Acts as a bridge between the midbrain and the medulla oblongata
2) Controls involuntary functions (sleep, hearing, balance)
53
What does the pons form? **
The anterior wall of the fourth ventricle
54
What is the medulla oblongata?
The inferior portion of the brainstem that regulates vital functions
55
What vital functions does the medulla oblongata regulate?
- heart rate
- respiratory rhythm
- blood pressure
- breathing
56
What does the medulla oblongata extend between?
Extends between the pons and the foramen magnum
57
What is the foramen magnum?
Opening of the skull
58
What is the medulla oblongata continuous with?
The spinal cord
59
What is the cerebellum?
Part of brain that is the centre for motor functions
60
How is the cerebellum divided?
Right and left hemispheres
61
Where is the cerebellum located?
Posterior to the pons and medulla oblongata
62
What does the cerebellum form? **
The posterior wall of the fourth ventricle
63
What separates the cerebrum from the cerebellum?
The tentorium cerebelli
64
What are the parts of the cerebellum?
1) Vermis
| 2) Cerebellar peduncles
65
What is the Vermis?
A midline structure in the cerebellum that connects it's two hemispheres
66
What are the cerebellar peduncles?
Nerve tracts that connect the cerebellum to other parts of the brain stem
67
What types of cerebellar peduncles are there?
Superior, middle and inferior
68
What are the fluid filled cavities in the brain called?
The ventricles
69
What are the ventricle components in the brain?
- Right and left lateral ventricles
- Third ventricle
- Fourth ventricle
70
Are the ventricles connected?
Yes, by channels
71
What do the ventricles do?
Produce and provide a pathway for cerebrospinal fluid to circulate
72
What is cerebrospinal fluid (CSF)?
A clear, colourless fluid that acts as a protective cushion and provides buoyancy to support the weight of the brain.
73
What produces CSF?
The choroid plexus of the ventricles
74
Where does CSF circulate?
In the subarachnoid space.
75
Where does CSF drain?
Into the blood via the dural sinuses
76
What are the largest ventricles?
The left and right lateral ventricles
77
What are the lateral ventricles?
Paired, C-shaped ventricles located within each cerebral hemisphere.
78
What are the lateral ventricles located lateral to?
The midline
79
What are the lateral ventricles separated by?
Separated medially by the cavum septum pellucidum
80
What do the lateral ventricles communicate with?
The third ventricle
81
What are the features of the lateral ventricles?
1) Body
2) Horns
3) Trigone
4) Interventricular Foramen
82
What is the body of the lateral ventricles?
The central portion
83
What are the horns of the lateral ventricles?
Extensions off of the body
84
How many horns do the lateral venticles have?
3
- Frontal/Anterior
- Occipital/posterior
- Temporal/inferior
85
What is another name for the trigone of the lateral ventricles?
Atria
86
What is the trigone of the lateral ventricles?
The triangular are of the body connected to all the horns
87
What is the interventricular foramen?
The channel between each lateral ventricle and the third ventricle
88
What is another name for the intraventricular foramen?
Foramen of Munro
89
Describe the relationship between the anterior and posterior horns of the lateral ventricles.
The anterior horns lie medial to the posterior horns.
90
Which horns are more superior on the lateral ventricles? The anterior or posterior?
The anterior are more superior
91
Where are the anterior horns of the lateral ventricles in reference to the foramen of munro?
Anterior
92
Where is the third ventricle in reference to the lateral ventricles?
Medial
93
What is the cavum septum pellucidum?
A thin triangular membrane located in the midline just inferior to the corpus callosum
94
What does the cavum septum pellucidum do?
Separates the medial walls of the lateral ventricles
95
What is the choroid plexus?
It lines areas within all the ventricles (each one)
96
What does the choroid plexus produce?
A continuous supply of cerebrospinal fluid
97
Where is the choroid plexus located in the lateral ventricles?
On the floor
98
Where is the choroid plexus located in the third ventricle?
On the roof
99
Where is the choroid plexus located in the fourth ventricle?
The posterior wall
100
What is the third ventricle?
A midline, slit like cavity that sits inferior to the lateral ventricles.
101
What forms the lateral walls of the third ventricle?
The left and right thalami
102
What runs through the third ventricle?
The massa intermedia of the thalamus
103
What is the cerebral aquaduct?
The connection between the 3rd and 4th ventricles.
104
What is another name for the cerebral aquaduct?
The aquaduct of sylvius
105
Where does the cerebral aquaduct extend?
Posteriorly from the third ventricle
106
What is the fourth ventricle?
A diamond shaped cavity that sits inferior and posterior to the third ventricle.
107
Where is the fourth ventricle located in reference to the pons?
Posterior
108
Where is the fourth ventricle located in reference to the cerebellum?
Anterior
109
What drains the fourth ventricle?
Three channels:
1 Foramen of Magendie
2 Foramen of Luschka
110
What is the foramen of magendie?
A single, posterior, midline opening that drains the 4th ventricle into the central canal of the spinal cord.
111
What is the foramen of luschka?
Two lateral openings that drain the fourth ventricle
112
What do the 3 openings that drain the 4th ventricle communicate with?
The subarachnoid space
113
What are the meninges?
3 distinct membranes that cover the brain and spinal cord
114
What are the functions of the meninges? (5)
- Protect neural cells
- Provide support for vessels
- Create venous sinuses in head
- Form partitions in the brain
- Allows circulation of CSF
115
What are the layers of the meninges? (Think of the PAD acronym - "they pad the brain").
1) Pia Mater (inner)
2) Arachnoid (middle)
3) Dura Mater (outer)
116
What does "dura mater" mean?
"Tough mother"
117
What is the dura mater?
Strong outer covering of the brain/spinal cord.
118
How many layers does the dura mater have?
Two
1) Periosteal layer
2) Meningeal layer
119
What is the periosteal layer?
Layer of dura mater that adheres to the bone
120
What is the meningeal layer?
Layer of dura mater that adheres to the brain and spinal cord
121
What lies inferior to the dura mater?
The subdural space
122
What are the dura mater partitions?
```
Falx cerebri (1)
Falx cerebelli (1)
Tentorium cerebelli (2)
```
123
What is the falx cerebri?
A partition in the dura mater that projects vertically between the cerebral hemispheres and runs along the longitudinal fissure.
124
What is the falx cerebelli?
A partition in the dura mater that vertically separates the cerebellar hemispheres
125
Where is the falx cerebelli in reference to the falx cerebri?
Inferior and posterior
126
What is the tentorium cerebelli?
It is a partition in the dura mater that folds horizontally in the transverse fissure.
127
The dural layers separate along fissures to form what?
The dural venous sinuses.
128
What drains into the dural venous sinuses?
All veins of the head
129
Where does the blood from the head drain into after the dural venous sinuses?
The internal jugular veins
130
What do the dural venous sinuses communicate with?
The arachnoid area
131
What are the major dural sinuses? (5)
1) Superior sagittal
2) Inferior sagittal
3) Straight
4) Transverse
5) Sigmoid
132
How does the blood from the head return to the heart?
The internal jugular veins via the venous sinuses
133
What is the arachnoid?
The middle layer of meninges that has a cobweb appearance.
134
What are arachnoid villi?
Outgrowths of arachnoid mater that penetrate the dura and project into the venous sinuses.
135
What is the function of arachnoid villi?
They allow for the reabsorption of fluid into the venous system.
136
What is another name for arachnoid villi?
Arachnoid granulations
137
What is the subarachnoid space?
Space between the arachnoid and pia layers that surrounds the brain and spinal cord and receives CSF from the ventricles allowing it to circulate.
138
What are the widened areas located in the subarachnoid space?
Cisterns
139
What are cisterns?
Pools of CSF located in the subarachnoid space, mainly at the base of the skull.
140
What is the largest pool of CSF fluid in the subarachnoid space?
Cisterna Magna
141
What is the Cisterna Magna continuous with?
The spinal space
142
What does "pia mater" mean?
Tender mother
143
What is the pia mater?
The inner meninges covering the brain made of highly vascular, delicate connective tissue.
144
What does the pia mater adhere to?
Directly to the surface of the brain, it follows the contour of the brain and enters the grooves and fissures.
145
What are the two main arterial routes from the heart to the brain?
1) Internal carotid arteries
| 2) Vertrebral arteries
146
What are the internal carotid arteries?
Branches off the common carotid arteries that take a tortuous route within the brain.
147
What do the internal carotid arteries connect to within the brain?
The middle cerebral arteries
148
What are the vertrebral arteries?
Branches of the subclavian arteries
149
Where to the vertrebral arteries enter the skull?
Through the foramen magnum
150
How do the vertrebral arteries travel?
They ascend cranially through the transverse foramina of the cervical spine
151
What do the vertrebral arteries unite to form?
The basilar artery
152
What is the circle of willis?
Arterial circle of major vessels at the base of the brain
153
What does the circle of willis unite?
The anterior and posterior arterial blood supplies
154
What does the circle of willis allow for?
1) Collateral blood flow between the hemispheres
| 2) Continuous blood flow to brain in case of damage in one area
155
What are the posterior cerebral arteries (R &L)?
Branch from the basilar artery
156
What are the posterior communicating artery (R & L)?
Run between the posterior cerebral arteries and the middle cerebral arteries.
157
What are the middle cerebral arteries? (R & L)
Branch from the internal carotid arteries
158
What are the anterior cerebral arteries? (R & L)
Bilateral anterior arteries
159
What is the anterior communicating artery?
Single mid line artery connecting the R and L anterior cerebral arteries
160
What is the spinal cord?
"Nerve cable" that is a continuation of the medulla oblongata, it tapers distally and and contains nerves associated with each vertebra.
161
What level does the spinal cord extend to?
L2
162
Where does the spinal cord widen?
At the cervical and lumbosacral widening
163
What area of the spinal cord tapers distally?
The Conus medullaris
164
What level should the Conus medullaris not extend past?
L@
165
How does the Conus medullaris appear on UT?
Hypoechoic area
166
What are the nerve bundles inferior to the conus medullaris called?
Cauda equine
167
How does the cauda equine appear on UT?
Thinner hyperechoic strands, "horse tail".
168
What is the slender strand from the conus medullaris to the coccyx?
Filum terminale
169
What is the function of the filum terminale?
It anchors the spinal cord
170
How does the filum terminale appear on UT?
A thicker hyperechoic strand
171
What secures the spinal cord laterally to the vertebral canal?
The denticulate ligaments
