The ventricular system Flashcards

1
Q

What is the ventricular system?

A

Series of CSF-filled interconnected spaces

Continuous with the subarachnoid space and central canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do the ventricles develop?

A

From the lumen of the neural tube
Lumen expands at cranial end
Ventricles associated with each part of the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name the ventricles

A
Lateral ventricles
Third ventricle
Cerebral aqueduct
Fourth ventricle
Central canal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the lateral ventricles

A

Two ventricles - very large
One for each cerebral hemisphere
Body, anterior, posterior and inferior horn corresponding to lobes of the hemispheres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What separates the lateral ventricles?

A

Septum pellucidum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a T1 weighted MRI

A

Fluid appears black

Good for structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a T2 weighted MRI

A

Fluid appears white

Good for fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What sits in the roof of the lateral ventricle?

A

Corpus callosum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What sits in the lateral wall of the lateral ventricles?

A

Caudate nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What sits in the floor of the inferior horn?

A

Hippocampus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do the lateral ventricles communicate with the third ventricle?

A

Through the interventricular foramen (also called foramen monro)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is the third ventricle located?

A

Slit like cleft between thalami

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What forms the roof of the third ventricle?

A

Fornix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do the third and fourth ventricles communicate?

A

Through cerebral aqueduct (aqueduct of sylvius)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the fourth ventricle surrounded by?

A

Hindbrain
Cerebellum posterior
Pons and medulla anterior
Cerebellar peduncles lateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the shape of the fourth ventricle

A

Rhomboid shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the fourth ventricle continuous with?

A

Continuous with the central canal of the spinal cord and subarachnoid space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Name the three foramen which exit into the subarachnoid space

A
  • Two Foramen of Luschka (lateral)

- One Foramen of Magendie (middle)

19
Q

What do the 3 foramina communicate with?

A

Cisterna Magna

20
Q

What produces CSF?

A

Choroid plexus

21
Q

What does the choroid plexus do?

A

Filters blood from branches of internal carotid and basilar arteries

22
Q

Where is the choroid plexus found?

A

Throughout the ventricles

23
Q

What is the structure of the choroid plexus?

A

Capillary network surrounded by cuboidal epithelium
Tight junctions between epithelial cells - prevents macromolecules from entering CSF- forms blood brain barrier. Permeable to water and CO2

24
Q

What happens during CSF production?

A

Blood filtered through fenestrated capillaries

Components transported through cuboidal epithelium into ventricles

25
Q

Describe the cuboidal epithelium

A

Specialized ependyma
Villi increase surface area
Active transport of CSF
Bidirectional

26
Q

What proportion of CSF is produced in the ventricles?

A

60%

27
Q

Why do the ionic compositions of plasma and CSF differ?

A

Regulation by active transport

Ideal for physiological functioning of neurons

28
Q

What is the main major difference between CSF and plasma?

A

Hardly any protein

29
Q

Describe CSF circulatory pathway

A

Lateral ventricles
Third ventricle
Fourth ventricle
Cisterna magna (subarachnoid space)
Down doral spinal subarachnoid space and up ventral spinal subarachnoid space
Over cerebral hemispheres into arachnoid granulations
or over cerebellum/cerebral hemispheres

30
Q

Where is the subarachnoid space found?

A

Lies between pia and arachnoid

Follows contours of the brain

31
Q

How is the subarachnoid space functionally important?

A

In contact with brain parenchyma

  • Transfer of micronutrients into brain
  • Removal of metabolites
32
Q

What are the arachnoid granulations?

A

Herniations of the arachnoid membrane through dura mater into venous sinuses
Mainly within the superior sagittal and transverse sinuses

33
Q

How is CSF absorbed?

A

CSF pressure must exceed that in venous sinuses
If venous pressure exceeds CSF pressure the tips of villi close off and prevents reflux of blood into the subarachnoid space
Arachnoid villi act as one-way valves

34
Q

How much CSF is produced each day?

A

500 ml

35
Q

What is the total volume in the system?

A

90-140 ml constantly moving and excess is absorbed by arachnoid granulations

36
Q

What are the main functions of CSF?

A

Hydraulic buffer to cushion brain against trauma
vehicle for removal of metabolites form CNS
Stable ionic environment for neuronal function (communicates with brain interstitial fluid via pia)
Transport of neurotransmitters and chemicals

37
Q

What colour is normal CSF?

A

Normally clear sterile fluid

38
Q

What colour is CSF in disease?

A

Discoloured in pathological states
Yellow (xanthochromia) - subarachnoid haemorrhage - lysis of red cells and haemoglobin release (converted to bilirubin)
Cloudy - Multiple sclerosis - protein content (gamma globulin) increase or in bacterial meningitis - leukocytes are increased, indicative of infection

39
Q

How is CSF sampled?

A

Taken by lumbar puncture at lumbar cistern - No spinal cord L3/4 in adults or L3/5 in children

40
Q

What is hydrocephalus?

A

Dilation of brain ventricles due to blocked CSF circulation, impaired absorption or over secretion
Increased intracranial pressure
Pressure on surrounding tissues affects neurological function
Can be congenital or acquired

41
Q

What are the symptoms of hydrocephalus?

A

Headache, vomiting, visual disturbances, papilledema, seizures, altered cognition, balance and coordination problems

42
Q

What is non communicating hydrocephalus?

A

Blockage within the ventricular system due to tumour, cyst, stenosis
CSF does not circulate over surface of the brain
Surgery: Inset shunt to reduce intracranial pressure

43
Q

What is dandy walker syndrome?

A

Congenital malformation of the cerebellum
Obstruction in the foramina of fourth ventricle (symmetrical dilation of lateral, third and fourth ventricles)
In infancy child’s head may become enlarged

44
Q

What is communicating hydrocephalus?

A

Obstruction in the arachnoid villi. Movement of CSF into venous sinus impaired
Eg. Impaired absorption following subarachnoid haemorrhage, trauma or bacterial meningitis