Ventricular System Flashcards
1
Q
What does the CSF do for the brain
A
Let’s it partially float in the skull cavity
2
Q
How ar the four ventricles of the brain connected
A
Thigh out narrow pipe like openings
3
Q
Where is the CSF primarily produced
A
Brain ventricles
4
Q
The CSF acts as a buffer to do what
A
Absorb stress transferred through the rigid skull
5
Q
CSF circulation
A
Ventricles to surface of brain and then drains in venous sinuses of skull
6
Q
CSF circulates ____________ from the ventricles to the subarachnoid space to the venous sinuses of the brain
A
Unidirectional
7
Q
Pathology due to disruption of CSF circulation causes what
A
Hydrocephalus
8
Q
What are the 4 brain ventricles
A
- 2 lateral ventricles
- third ventricle
- fourth ventricle
9
Q
CSF production and circulation
A
- choroid plexus
- expend y’all lining of choroid plexus
- choroid plexus produces the CSF
10
Q
What produces the CSF
A
Choroid plexus
11
Q
Disruption of CSF circulation
A
Hydrocephalus
12
Q
Where are the lateral ventricle located
A
In each hemisphere
13
Q
Where is the third ventricle located
A
Midbrain
14
Q
Where is the fourth ventricle located
A
Between the pons and medulla, and the cerebellum
15
Q
Located in the caudal medulla and spinal cord; usually not patent over much of its existence
A
Central canal
16
Q
Communications between ventricles
A
- interventricular foramina (of monro) - lateral and third ventricle
- cerebral aqueduct (Sylvius)
- foramina of Lushka and Magendie
17
Q
Which lobes do the C shaped lateral ventricles course through?
A
All of the lobes of the cerebral hemispheres in which they reside
18
Q
What are the five parts of each lateral ventricle
A
- anterior horn (frontal lobe)
- body (frontal and parietal)
- posterior horn (occipital)
- inferior horn (temporal)
- atrium or trigone (body and posterior and inferior horns meet here )
19
Q
What is the third ventricle
A
A midline slit in the diencephalon
20
Q
What is the lateral wall of the third ventricle
A
A medial surface of the thalamus and hypothalamus and part of the hypothalamus forms its floor
21
Q
Roof of the third ventricle
A
Thin membranous roof containing choroid plexus
22
Q
Anteriorly, ther third ventricle ends at the __________
A
Lamina terminalis
23
Q
At the posterior end of hte maillary body, the third ventriclal does what
A
Narrows fairly abruptly to become the cerebral aqueduct (sylvius)
24
Q
Where does the interventricular foramen lay
A
In the anterior part of each wall of the third ventricle
25
Recess of the third ventricle, inferiorly
Inferiorly, the optic recess lies in front of the optic chiasm at the base of the lamina terminalis
26
Where does the infundibular recess of the third ventricle lay
Behind the chiasm
27
Superior recess of third ventricle
Pineal recess invades the stalk of the pineal gland
28
Suprapineal recess of third ventricle
Lies just anterior to stalk of pineal gland
29
Where is the fourth ventricle situated
Between the cerebellum posteriorly and the pons and rostral medulla anteriorly
30
Shape of fourth ventricle
Like a tent with a doubly peaked roof, the peaks protruding into the cerebellum
31
The portion of the roof of the fourth ventricle rostral to the peak
Superior medullary velum
32
The portion of the roof of the fourth ventricle caudal to the peak
Inferior medullary velum
33
The floor of the fourth ventricle is referred to as
Rhomboid fossa
34
At the lateral point of the floor of the ventricle becomes a narrow tube that proceeds anteriorly and curves around the brainstem. This tubular prolongation is the what
Lateral recess of the fourth ventricle, aka the foramen of Lushka
35
Where does CSF exit the system
Foramen of Luschka
36
What does hte fourth ventricle communicate with
Subarachnoid cisterns
37
What do the lateral and third ventricle communicate with
Only with other parts of the ventricular system, each having only one draining opening
38
What does the lateral ventricle communicate with
Each other and the 3rd ventricle through the interventricular foramen (Monroe)
39
How does the 3rd ventricle communicate with the 4th ventricle
Through the relatively long canal- the cerebral canal aka aqueduct of Sylvius
40
What happens if there is obstruction of the ventricles
Block the free circulation of CSF
41
How many aperture in the fourth ventricle
3
| Through which the ventricular system communicates freely with subarachnoid space
42
What are the 3 apertures of the 4th ventricle
--median aperture (foramen of magendie)
-the two lateral apertures
(Foramina of Luschka)
43
Clear, colorless fluid surrounding the brain and spine
CSF
44
Where is CSF produced
Choroid plexuses
45
Functions of CSF
Acts as a cushion or buffer
46
What does CSF occupy
Ventricular system and the subarachnoidal space
47
How does CSF circulate
Unidirectionally from ventricles to surface of brain
48
How is CSF propelled
Forward passively through the pulsation of the brain circulation, no active propulsion
49
How much CSF within and around brain and spinal cord
150-200ml
50
How much CSF in ventricles
25ml
51
What is turnaround time for CSF
3.5 times a day
52
CSF circulation
Lateral ventricles--3rd ventricle--4th ventricle--subarachnoid space--venous sinuses
53
All four ventricles contain strands of highly convoluted and vascular membranous material called ________
Choroidal plexus
54
Lateral ventricle and chorda plexus
There is a band of choroid plexus in each arterial ventricle
55
The plexus is enlarged in the region of the atrium, and here it is called the ______
Glomus
56
Choroid plexus and age
Becomes calcified
57
Choroid plexus in the lateral ventricles
Grows through the interventricular foramen, forming part of its posterior wall
58
How is the choroid plexus formed
By an evagination of the ependymal layer of cells containing arterioles, capillaries, and venules
59
Epedndymal layer of choroid plexus
Specialized as cuboidal, secretory epithelium, the choroid epithelium
60
How does the choroid plexus generate CSF?
By filtering blood
61
Fenestrated endothelium in choroid capillaries
Allows plasma and fluid through, but blocks cells
62
Draining of CSF
- 4th ventricle through foramina, up and over cerebral hemispheres, through arachnoid Vvilli and into the superior sagittal sinus
- some goes into subarachnoid space around spinal cord. It makes it way caudally to lumbar cistern
- most is returned to venous system through arachnoid villi that penetrate dural sleeves
63
Does the CSF in the subarachnoid space penetrate through to the pia mater?
No
64
Small protrusions of the arachnoid through the dura mater
Arachnoid granulation (arachnoid villi)
65
What do the arachnoid granulation (villi) allow
They protrude into the venous sinuses of the brain and allow CSF to exit the sub arachnoid space and enter the blood stream
66
Where do the largest arachnoid granulation lie?
Superior sagittal sinus
67
What is produced by arachnoid granulation on the inner surface of cranial bones
Small pits called granular fovea
68
What are smaller arachnoid granulation called
Villi
69
What do the arachnoid granulation act as
One way valves
70
Rate of CSF production independent of what
Blood pressure and intra-ventricular pressure
71
Fluid continues to be produces even if the path of its circulation is blocked. When this happens, CSF pressure rises, ventricles expand creating condition called
Hydrocephalus
72
Hydrocephalus can result from
- excess production of CSF
- blockage of CSF circulation
- deficiency in CSF reabsorption
- ex vacuo
73
What is the most common cause of hydrocephalus
Blockage of CSF circulation
74
Blockage of CSF by tumors of the choroid plexus (papilloma)
Hydrocephalus
75
Ventricles still communicate, blockage is outside
Communicating hydrocephalus
76
Blockage is within the ventricles (aqueduct)
Non communicating hydrocephalus
77
Symptoms of increased intracranial pressure
- headache
- nausea/vomitting
- papilledema, except in normal pressure hydrocephalus
- changes in consciousness (sleepiness to coma)
- brain herniation (life threatening)
78
What type of hydrocephalus effects elderly most
Normal pressure hydrocephalus
79
In 50% of cases of normal pressure hydrocephalus, an idiopathic __________ increase in ICP occurs
Intermittent
80
Some causes of normal pressure hydrocephalus
- meningitis
- subarachnoid hemorrhage
- atherosclerosis
81
What does normal pressure hydrocephalus result from
Decreased reabsorption of CSF at the arachnoid granulations
82
Presentation of normal pressure hydrocephalus
Classic triad of bladder incontinence dementia, and ataxia (wet, wacky, wobbly)
83
What is there no presence of in normal pressure hydrocephalus
No papilledema or headaches
84
Diagnosis for normal pressure hydrocephalus q
Clinical signs, with CT/MRI showing ventriculomegaly
85
Pseudotumor cerebri is 8-10 times more common in _____
Women
86
What is pseudotumor cerebri associated with
Obesity and oral contraceptives
87
Identified cause of pseudotumor cerebri
Usually none
88
Presentation of pseudotumor cerebri
Headache, visual disturbances such as diplopia and sixth cranial nerve palsy (abducens)
89
What is a characteristic sign of pseudotumor cerebri
Papilledema
90
Cranial pressure in pseudotumor cerebri
Increased
