Ventricles & CSF Flashcards
1
Q
what is a ventricle of the brain
A
internal cavity of the brain filled with cerebrospinal fluid
2
Q
what is CSF
A
a protein rich fluid essential for brain function
3
Q
what part of the neural tube do the lateral ventricles develop from
A
prosencephalon
4
Q
where are the lateral ventricles found
A
near the cerebral hemispheres
5
Q
what part of the neural tube does the third ventricle develop from
A
diencephalon
6
Q
where is the third ventricle found
A
near the thalamus and hypothalamus
7
Q
what part of the neural tube does the fourth ventricle develop from
A
hindbrain
8
Q
where is the fourth ventricle found
A
near the pons, medulla obongata and cerebellum
9
Q
three parts of the brain developmentally
A
forebrain, midbrain and hindbrain
10
Q
what foes the forebrain consist of
A
cerebrum, thalamus and hypothalamus
11
Q
what developmental parts of the brain is the brainstem made up of
A
midbrain and hindbrain
12
Q
what does the hindbrain consist of
A
pons, medulla oblongata and the cerebellum
13
Q
four primary divisions of the neural tube
A
- prosencephalon
- mesencephalon
- rhombencephalon
- spinal cord
14
Q
two subdivisions of the prosencephalon
A
telencephalon and deincephalon
15
Q
what is the telencephalon a subdivision of
A
prosencephalon
16
Q
what is the diencephalon a subdivision of
A
prosencephalon
17
Q
what are the main constituent parts of the telencephalon
A
- olfactory lobes
- cerebral hemispheres
18
Q
what cavities does the telencephalon contain
A
- lateral ventricles
- rostral portion of 3rd ventricle
19
Q
main constituent parts of the diencephalon
A
- epithalamus
- hypothalamus
- thalamus
- infundibulum
20
Q
what cavities are contained by the diencephalon
A
most of the 3rd ventricle
21
Q
main constituent parts of the mesencephalon
A
colliculi/corpora quadrigemini
cerebral peduncle
22
Q
cavities contained by the mesencephalon
A
cerebral aquaduct
23
Q
main subdivisions of the rhombencephalon
A
- metencephalon
- mylencephalon
24
Q
what is the metencephalon a subdivision of
A
rhimbencephalon
25
what is the mylencephalon a subdivision of
rhombencephalon
26
main constituent parts of the metencephalon
cerebellum
pons
27
cavities contained by metencephalon
4th ventricle
28
main constituent parts of the mylencephalon
medulla oblongata
29
why is the spinal cord different from other main divisions of the neural tube
it has no subdivisions or main constituent parts
30
what cavity is contained by the spinal cord
the central canal
31
how do the lateral ventricles communicate with the third ventricle
through the interventricular foramen (of monro)
32
where is the anterior horn of the lateral ventricles
frontal lobe
33
where is the posterior horn of the lateral ventricles
occipital lobe
34
where is the inferior horn of the lateral ventricles
temporal lobe
35
where is the roof of the lateral ventricles
under the surface of the corpus collosum
36
what is the floor of the lateral ventricles
body of caudate nucleus and lateral margin of thalamus
37
do the lateral ventricles communicate with eachother
no
38
why don't the lateral ventricles communicate with eachother
their medial wall is the septum pellucidum
39
what is the interventricular foramen abounded by
* anteriorly: anterior column of fornix
* posteriorly: anterior end of thalamus
40
what is the choroid plexus
a network of blood vessels and cells found in ventricles
41
third ventricle shape
narrow and slit-like
42
third ventricle boundaries
thalamus and hypothalamus
43
fourth ventricle shape
tent-like
44
how do the third and fourth ventricles communicate
by the cerebral aqeduct (or aqueduct of sylvius)
45
what is the fourth ventricle continuous with
* the central canal of the spinal cord
* through its three foramina with the subarachnoud space
46
what are the three foramina of the third ventricle
* laterally, the foramen of Lushka (x2)
* posteriorly the Magendie (x1)
47
where is the fourth ventricle located
behind the pons and medulla oblongata and anterior to the cerebellum
48
what is the terminal ventricle
a small dilation at the inferior end of the central canal
49
colour of CSF
colourless
50
what does CSF contain
* inorganic salts (similar to those in plasma)
* glucose
* traces of protein
* lymphocytes
51
what is the pressure of CSF
8-15mmHg
52
total volume of CSF
usually 135-150 mls
53
four functions of CSF
* protection
* buoyancy
* excretion of waste products
* endocrine medium
54
protection
| CSF function
protects brain by buffering it
55
buoyancy
| CSF function
because the brain is immersed in fluid, the net weight of the brain is reduced from about 1400gm to about 50gm, pressure at the base of the brain is reduced
56
excretion of waste products
| CSF function
one-way flow from CSF to the blood takes potentially harmful metabolites, drugs and other substances away from the brian
57
endocrine medium
| CSF function
transports hormones to other areas of the brain. hormones released into CSF can be carried to remote sites of the brain where they may act
58
what is a choriod plexus
Cuboidal epithelial cells (ependyma) surrounding a core of capillaries and loose connective tissue - much folded
59
where is CSF formed
mostly in the choroid plexuses of lateral, 3rd and 4th ventricles
and some originates from the ependynal cells actually lining the ventricles
60
how much CSF is produced daily
500ml
61
how many times a day is CSF recycled
4 times
62
why is CSF recycled
to clean out metabolites and toxins
63
example of a toxin recycled by CSF
beta amyloid
64
what is beta amyloid
a plaque that cause Alziemer's
65
where does CSF flow after its formed
into the subarachnoid space through aptertures
into the cisterna magna through the lateral apertures and the medial aperture
66
how is CSF flow facilitated
pulsations of the cerebral and spinal arteries and the movements of the vertebral column, respiration, coughing and the changing of body positions
67
how is CSF absorbed back into the bloodstream
* Small protrusions of the arachnoid through the dura mater into the venous sinuses of the brain allow CSF to exit the sub-arachnoid space and enter the blood stream
* When the CSF pressure is greater than the venous pressure, CSF will flow into the blood stream
* Arachnoid villi act as one way valves
* If CSF pressure is less than the venous pressure, the arachnoid villi will not let blood pass into the ventricular system
68
what is hydrocephalus
* too much CSF
* due to an obstruction somewhere within the ventricular system causing problems with CSF absorption
69
communicating hydrocephalus
- occurs when there is full communication between the ventricles and subarachnoid space
- most often associated with defective absorption of CSF
- occasionally caused by venous drainage insufficiency
- rarely caused by overproduction of CSF
70
non-communicating hydrocephalus
occurs when CSF flow is obstructed, resulting in a lack of communication between ventricles and subarachnoid space
71
what does a shunt procedure do for hydocephalus
relieves pressure by removing excess CSF
72
what is papilledema
- The subarachnoid space around the optic nerve is not usually filled with CSF
- A rise of CSF pressure may compress thin walls of the retinal vein as it crosses the extension of the subarachnoid space to enter the optic nerve
- This will result in bulging forward of the optic disc, and edema of the disc which results in the condition of papilledema
73
what does persistent papilledema lead to
optic atrophy and blindness
74
what can cause an increase of pressure around the brain
- meningitis
- oedema
- tumour
- cerebral abscess
- haematoma
75
what does it mean if CSF is cloudy
indicates presence of polymorphonuclearleukocytes or an excessive quantity of proteins
76
what does an increase of white bloos cells in CSF indicate
inflammation of meninges or encephalitis
77
what does an increase in protein content of CSF indicate
change in vascular permeability (more protein can then enter CSF)
78
what causes blood in the CSF
contamination brought about by a puncture of a vertebral vein by spinal tap needle
79
what causes yellow colouration or xanthochromia of CSF
presence of oxyhaemoglobin in fluid some hours after subarachnoid haemorrhage
