3- Blood Supply and Meninges Flashcards
1
Q
What percentage of the total body weight is made up by the brain?
A
2%
2
Q
What percentage of total oxygen inspired does the brain consume ?
A
20%
3
Q
What is a stroke?
A
Decreased blood supply to the brain over a long period of time
4
Q
How common is a stroke in over 65s?
A
1 in 100
5
Q
What are the 2 pairs of arteries that supply the brain called?
A
- Vertebral artery
2. Internal carotid artery
6
Q
What is the vertebral artery a branch of?
A
The subclavian artery
7
Q
What joins the vertebral and Internal carotid arteries?
A
The circle of Willis at the base of the brain
8
Q
Where does the vertebral artery ascend?
A
Ascend in the neck through transverse foramen of the cervical vertebrae
Enters the skull the skull via the foramen magnum
9
Q
What do the vertebral arteries do once they enter the skull?
A
They fuse forming the Basilar artery
10
Q
The Internal carotid artery is a branch of what?
A
Our common carotid artery
11
Q
How does the internal common carotid artery enter the skull?
A
Via the carotid canal
12
Q
Name the branches of the vertebral artery that supply the spinal cord
A
Anterior spinal artery
Posterior spinal artery
13
Q
When are the anterior and posterior branches formed?
A
Prior to the vertebral arteries fusing in the skull
14
Q
What does the vertebral artery branch into prior to fusing?
A
- The anterior spinal artery
- The posterior spinal artery
- The posteriors inferior cerebellar artery
15
Q
What does The posteriors inferior cerebellar artery supply?
A
The posteriors inferior cerebellum
16
Q
What does the basilar artery branch into?
A
- Anterior inferior cerebellar artery (AICA)
- Pontine artery
- Superior cerebellar arteries
- Posterior cerebral artery
17
Q
What does The Anterior inferior cerebellar artery supply?
A
The anterior inferior cerebellum
18
Q
What does the pontine artery supply?
A
Supply the pons
19
Q
What does the superior cerebellar artery supply?
A
the superior aspect of the cerebellum
20
Q
Why is the posterior cerebral artery called the instead of cerebellar?
A
Because it goes to the back of the cerebrum
21
Q
Name the branches of the internal common carotid artery
A
- Middle cerebral artery
2. Anterior cerebral arteryW
22
Q
What forms the circle of Willis?
A
The closing of the middle and anterior cerebral arteries into a circle
23
Q
Name the 3 pairs of cerebral arteries
A
Post. Cerebral
Middle Cerebral
Ant. Cerebral
24
Q
Name the 3 pairs of cerebellar arteries
A
Post. Inf . Cerebellar
Ant. Inf. Cerebellar
Sup. Cerebellar
25
What does the circle of willis do?
Interconnects the internal carotid and vertebral – basilar system
26
What does the circle of willis surround?
Surrounds optic chiasm and hypothalamus
27
What does the circle of willis ensure?
Ensures that blood flow doesn't decrease if any of the arteries are blocked
28
What is a berry Aneurysm?
Abnormal dilations around the circle of Willis or at the points of arterial branching within the brain
29
What can Berry Aneurysms cause?
If they rupture they can lead to a vascular stroke
30
What percentage of strokes are caused by berry aneurysms?
10%
31
What does the anterior cerebral artery (ACA) supply ?
1. Superior and medial areas of frontal and parietal lobes
| 2. Corpus callosum
32
What does the middle cerebral artery (MCA) supply ?
Lateral areas of frontal, temporal and parietal lobes
33
What does the posterior cerebral artery (PCA) supply ?
Occipital lobe
| Inferior and medial surface of temporal lobe
34
Which artery is affected if their is a lesion in the primary auditory cortex
MCA
35
Which artery is affected if their is a lesion in the primary visual cortex
PCA as it is in the occipital lobe
36
What are deep/perforating arteries?
Other smaller beached off the arterial circle
37
What are is another name for the deep arteries?
Striate arteries (delicate)
38
What do deep/ perforating/ striated arteries supply?
1. Deep nuclei
2. Deep grey matter
3. Internal capsule
4. Supply Includes major descending motor pathway
39
What is the internal capsule
Made up of white matter
| It Is the major fibre bundle to and from cerebral cortex
40
If their was an injury to any of the striate arteries what could happen
You might experience some motor deficits
41
Where is all the blood from the brain drained into?
The internal jugular veins
42
What are meninges?
Protecting airbags
43
How many layers of meninges do we have and what are they called?
We have 3 layers:
1. Dura mater
2. Arachnoid mater
3. Pia mater
44
What do the meninges cover?
The central nervous system:
| The brain and spinal cord
45
What is the first layer of meninges called?
Dura mater
46
Describe the dura mater
It is a tough fibrous layer that surrounds and protects the brain
47
Name the meninges under the dura mater
The arachnoid mater
48
Describe the arachnoid mater
It is shiny and translucent
It is thin and delicate
Spider weblike
Very vascular
49
What is the inner most later of meninges called?
The Pia mater
50
Describe the Pia mater
It is very thin
It is tightly applied into the surface of the brain and cervix of the spinal cord
Cant really be separated
51
What path does the Pia mater follow?
Follows the cortex of the brain and follows the sulk and gyri of the brain
52
What is special about the dura mater?
It has 2 layers:
The outer periosteal layer of dura
The Inner meningeal layer of dura
53
What is the outer periosteal layer of the dura?
It is firmly attached to the bone of the skull
54
What is the inner meningeal layer of the dura?
It is firmly attached to the arachnoid
55
What is the space between the arachnoid and Pia called?
The Subarachnoid space
56
What is found in the Subarachnoid space?
cerebrospinal fluid (CSF)
57
Are both the layers of the dura mater attached to each other?
Yes apart from at certain points
58
What do the 2 layers of dura allows
For dural infoldings (partitions) only at specific areas
59
What forms as a result of dural infoldings?
A space between the outer and inner layer of the dura mater called a dural sinus
60
What are found in the dural sinuses?
Venous blood
61
Which dural infolding separates the 2 hemispheres?
The Faix cerebri
62
What can happen if a vessel in the brain bursts?
Can suffer from a haemorrhage
63
What happens an artery bursts between the periosteal layer and the skull?
The patient can suffer from a Epidural haemorrhage (hematoma)
64
The bursting of which artery can lead to an epidural haemorrhage?
A torn meningeal artery
65
What happens a blood vessel bursts between the meningeal dura and the arachnoid?
Accumulation of blood causing a subdural haemorrhage
66
The bursting of which vessel can lead to a subdural haemorrhage?
Torn bridging vessels
67
What happens a blood vessel bursts in the subarachnoid space
Accumulation of blood causing a subarachnoid haemorrhage
68
The bursting of which vessel can lead to a Subarachnoid haemorrhage?
Torn cerebral arteries
69
Where is the Falx cerebri found?
Between the cerebral hemispheres
70
Where is the Tentorium cerebelli found?
between occipital lobes and cerebellum
71
Name some sinuses found in the brain?
1. Superior sagittal sinus
2. Transverse sinus
3. Inferior sagittal sinus
72
Where are Dural Venous Sinuses found?
Located within the dural infoldings
73
Where do dural venous sinuses receive blood from?
Little superficial veins
74
Where does the superior sagittal sinus empty blood into?
To the confluence of sinuses
75
Where does the inferior sagittal sinus empty blood into?
The straight sinus
76
Where do Deep veins empty blood into?
The great cerebral vein and the straight sinus
77
Once in the straight sinus where does all the blood go?
Into the. confluence of sinus
78
Once in the confluence of sinuses where does all the blood go?
Into the transverse sinus
79
What does our transverse sinus become?
The sigmoid sinus
80
Where does the sigmoid sinus drain blood into?
Our internal jugular veins
81
Briefly describe the pathway of venous drainage starting at the superficial veins
1. Superficial veins
2. Superior sagittal sinus
3. Confluence of sinuses
4. Transverse sinuses
5. Sigmoid sinus
6. Internal jugular veins
82
Briefly describe the pathway of venous drainage starting at the deep veins
1. Deep veins
2. Internal cerebral veins
3. Straight sinus
4. Confluence of sinuses
5. Transverse sinuses
6. Sigmoid sinus
7. Internal jugular veins
83
Name the 3 meninges of the spill cord
1. Dura mater
2. Arachnoid
3. Pia
84
What is found between the dura and the vertebrae (SPINAL CORD)?
The epidural space occupied by fat
85
What is found in the sub arachnid space?
Cerebral spinal fluid
86
What is the pia firmly attached to in the spinal cord?
The cord
87
What projects out of the Pia?
Denticulate ligaments
88
What do Denticulate ligaments
| do?
They anchor the spinal cord
89
What is found in our ventricular system?
Fluid filled cavities
90
Name the 5 ventricles in out brain?
1. Lateral ventricle
2. Third ventricle
3. Cerebral aqueduct
4. Fourth ventricle
5. Central canal
91
What does the central canal make upon an adult brain?
he ventricular system as it fils up with fluid
92
What connects our lateral ventricle to our third ventricle?
The interventricular foramen
| foramen of Monroe
93
What connects our 4th ventricle to our 3rd ventricle?
The cerebral aqueduct
94
What connects our 4th ventricle to the rest of the subarachnoid space?
2 Lateral apertures (foramina of Luschka)
| and a Median aperture (foramen of Magendie)
95
What does the lateral ventricle follow?
The shape of the brain
96
Where is the 3rd ventricle located?
Between the 2 thalami
97
Where is the 4th ventricle located?
Between the pons and the cerebellum
98
Why are ventricles formed in the brain?
due to the enormous growth and distortion an elaborate system of ventricles are formed.
99
What do ventricle develop as?
dilations from the central canal of the embryological neural tube
100
Name the 4 ventricles that make up the brain
2 x lateral ventricles
3rd ventricle:
4th ventricle:
101
Where are the 2 lateral ventricles located?
one within each cerebral hemispheres. Follow c-shape of hemispheres.
102
What do the ventricles all contain?
Contain choroid plexus which produce CSF
103
What allows CSF to escape the ventricular system and where does it go?
Series of apertures allow CSF to escape ventricular system into subarachnoid space
104
Briefly describe the schematic view of the ventricular system
1. Lateral ventricles
2. Interventricular foramen
3. 3rd ventricle
4. Cerebral aquaduct
5. 4th ventricle
6. Lateral and median apertures
7. Subbarachnoid space
105
Describe Cerebrospinal fluid (CSF)
it is a clear and colourless solution
106
What is CSF derived from and where is it made?
The blood
| Produced in ventricles by specialised areas of ventricular lining: choroid plexus
107
What is CSF contain?
Contains glucose and inorganic salts, little protein, few cells.
108
What does CSF fill?
Fills subarachnoid space and ventricular system of brain.
109
Why is the CSF important?
It Provides physical protection and chemical stability for CNS
110
Where is CSF made?
The choroid plexus
| in each ventricle
111
Which cells filtrate blood an produces CSF?
Ependyma cells
112
Describe the path CSF takes
1. Lateral ventricle
2. Foramina of Monroe
3. Third ventricle
4. Cerebral aquaduct
5. Fourth ventricle
6. Foramina of Luschka and Magendie
7. Sub arachnid space
8. Reabsorbd into sinuses
113
How is CSF reabsorbed into the sinuses?
Via the arachnoid granulations (villi)
114
What are arachnoid granulations (villi)?
extensions of arachnoid matter into dural sinuses
| predominantly the superior sagittal sinus
115
What happens if we have a blockage in the CFS drainage system?
More CSF will produced than drained leading to build CSF
| This results in hydrocephalus
116
What can hydrocephalus cause?
Build up pressure in the skull
117
what can hydrocephalus cause in children?
Expansion of the skull as pressure builds up in the brain
118
What do doctors do to try and treat Hydrocephalus?
They insert a needle into the ventricles to remove some of the CSF liquid and hope to reduce pressure in the skull
119
How much CSF is produced daily?
About 500ml/day.
120
What are the 4 functions of CSF?
1. Buoyancy: Brain and spinal cord float to reduce traction
2. Cushioning effect to dampen trauma
3. Transport of substances: Nutrients, dissolved gasses, removal of metabolites
4. Provides stable environment
121
What supplies the Inferior and medial surface of temporal lobe?
The posterior cerebral arteries
122
What is the epidural space occupied by?
Fat
123
Through which foramen does the vertebral artery enter the skull?
The foramen magnum
124
What do the anterior and posterior spinal arteries supply?
The spinal cord
125
What supplies the Superior and medial areas of frontal and parietal lobes?
The anterior cerebral artery
126
What supplies the Lateral areas of frontal, temporal and parietal lobes?
The middle cerebral arteries
127
What supplies the posteriors inferior cerebellum?
The posteriors inferior cerebellar artery
128
What supplies the Anterior inferior cerebellum?
The anterior inferior cerebellar artery (AICA)
129
What supplies the pons?
The pontine arteries
130
What empties blood to the straight sinus?
The inferior sagittal sinus and the deep veins
131
What is the space between the occipital loves and the cerebellum called?
The Tentorium cerebelli
132
What supplies the superior aspect of the cerebellum?
The superior cerebellar artery
133
Name the clinical condition associated with Abnormal dilations around the circle of Willis?
Berry aneurysm
134
What is the space between the cerebral hemispheres called?
The Falx cerebri
135
What supplies the Corpus callosum?
The anterior cerebral artery
136
What causes 10% of vascular strokes?
Berry aneurysms
137
What supplies the Occipital lobe?
The posterior cerebral arteries
138
What is the Subarachnoid space?
The space between the arachnoid and pia
139
What is a dural sinus?
Space between the inner and outer dura mater formed due to dural infoldings
140
What empties blood to the confluence of sinuses?
The superior sagittal sinus
141
What empties blood into the great cerebral vein?
Deep veins
142
What is the epidural space?
Space between the dura and vertebrae in the spinal cord
143
What are Denticulate ligaments?
They are projections from the pia that anchor the spinal cord
144
What is the foramen of Monroe?
An intraventricular foramen that connect the lateral ventricle to the third ventricle
145
What is the cerebral aqueduct?
It connects our 3rd ventricle to our 4th ventricle
146
What does the choroid plexus produce?
Cerebrospinal fluid (CSF)
147
What is hydrocephalus?
When there is a blockage somewhere in the CSF drainage system resulting in more CSF being produced than reabsorbed
148
What does CSF stand for?
Cerebrospinal fluid (CSF)
