Ventricular System Flashcards
What are the ventricles?
- Series of CSF-filled interconnected spaces
- Continuous with the subarachnoid space and central canal
Ventricular System
- Series of …-filled interconnected spaces
- Continuous with the … space and central canal
- Series of CSF-filled interconnected spaces
- Continuous with the subarachnoid space and central canal

Subarachnoid space - Between … and … layer of meninges
Subarachnoid space - Between pia and arachnoid layer of meninges
Development of the ventricles
- … forms neural tube
- … of neural tube becomes ventricles and central canal
- Ependymal layer lines … and central canal
- Neuroectoderm forms neural tube
- Lumen of neural tube becomes ventricles and central canal
- Ependymal layer lines ventricles and central canal

Development of the ventricles
- Lumen expands at … end to form ventricles
- There is a … associated with each part of the brain
- Lumen expands at cranial end to form ventricles
- There is a ventricle associated with each part of the brain

Lateral Ventricles
- Two lateral ventricles (surrounded by ….)
- Very large …-shape (one for each cerebral hemisphere)
- Divided into:
- Body - … lobe
- Anterior horn - … lobe
- Posterior horn - .. lobe
- Inferior horn - … lobe
- Two lateral ventricles (surrounded by telencephalon)
- Very large C-shape ( one for each cerebral hemisphere)
-
Divided into:
- Body - parietal lobe
- Anterior horn - frontal lobe
- Posterior horn - occipital lobe
- Inferior horn - temporal lobe

Lateral Ventricles
- … lateral ventricles (surrounded by telencephalon)
- Very large C-shape ( one for each cerebral hemisphere)
- Divided into:
- … - parietal lobe
- .. horn - frontal lobe
- … horn - occipital lobe
- … horn - temporal lobe
- Two lateral ventricles (surrounded by telencephalon)
- Very large C-shape ( one for each cerebral hemisphere)
-
Divided into:
- Body - parietal lobe
- Anterior horn - frontal lobe
- Posterior horn - occipital lobe
- Inferior horn - temporal lobe

What is the best imaging to view the lateral ventricles?
MRI

Lateral ventricles on MRI
- CSF on T1 weighted appears …
black

Lateral ventricle borders
- Septum … separates lateral ventricles - both white and grey matter
- Corpus callosum sits in …
- … nucleus sits in lateral wall
- … (part of limbic system) sits in floor of inferior horn
- Septum pellucidum separates lateral ventricles - both white and grey matter
- Corpus callosum sits in roof
- Caudate nucleus sits in lateral wall
- Hippocampus (part of limbic system) sits in floor of inferior horn

Lateral ventricle borders
- … … separates lateral ventricles - both white and grey matter
- Corpus callosum sits in roof
- Caudate nucleus sits in lateral wall
- Hippocampus (part of limbic system) sits in floor of … horn
- Septum pellucidum separates lateral ventricles - both white and grey matter
- Corpus callosum sits in roof
- Caudate nucleus sits in lateral wall
- Hippocampus (part of limbic system) sits in floor of inferior horn

Interventricular foramen
- Lateral ventricles communicate with the … ventricle through the Interventricular foramen
- (also called Foramen of …)
-
Lateral ventricles communicate with the third ventricle through the Interventricular foramen
- (also called Foramen of Monro)

Lateral ventricles communicate with the third ventricle through the ….
Interventricular foramen

Third ventricle
- Third ventricle appears as a …-like cleft
- Thalami sit in lateral walls
- … forms the roof
- Third ventricle appears as a slit-like cleft
- Thalami sit in lateral walls
- Fornix forms the roof

Summary of associated structure - Ventricles

Cerebral aqueduct
- … ventricle communicates with … ventricle through the cerebral aqueduct
- Also called Aqueduct of Sylvius
- Surrounded by the …
- Third ventricle communicates with fourth ventricle through the cerebral aqueduct
- Also called Aqueduct of Sylvius
- Surrounded by the midbrain

Third ventricle communicates with fourth ventricle through the … …
Third ventricle communicates with fourth ventricle through the cerebral aqueduct

Fourth ventricle
- Surrounded by …:
- … posterior
- Pons and medulla anterior
- Cerebellar peduncles lateral
- superior and inferior medullary … form the roof
- Continuous with the central canal of the spinal cord and … space
- Surrounded by hindbrain:
- Cerebellum posterior
- Pons and medulla anterior
- Cerebellar peduncles lateral
- superior and inferior medullary velum form the roof
- Continuous with the central canal of the spinal cord and subarachnoid space

Fourth ventricle
- Surrounded by hindbrain:
- Cerebellum posterior
- … and … anterior
- … peduncles lateral
- superior and inferior … velum form the roof
- Continuous with the … canal of the spinal cord and subarachnoid space
-
Surrounded by hindbrain:
- Cerebellum posterior
- Pons and medulla anterior
- Cerebellar peduncles lateral
- superior and inferior medullary velum form the roof
- Continuous with the central canal of the spinal cord and subarachnoid space

How does the fourth ventricle communicate?
- Three foramina exit into subarachnoid space:
- 2 Foramen of Luschka (lateral)
- 1 Foramen of Magendie (middle)

Fourth ventricle communication
- Three foramina exit into subarachnoid space:
- 2 Foramen of … (lateral)
- 1 Foramen of … (middle)
- Three foramina exit into subarachnoid space:
- 2 Foramen of Luschka (lateral)
- 1 Foramen of Magendie (middle)

In a coronal view of the fourth ventricles, what is the shape?
Rhomboid (diamond) shape of fourth ventricles

CSF produced by … …
CSF produced by choroid plexus
Choroid Plexus
- … produced by choroid plexus
- Filters blood from branches of internal carotid and basilar arteries
- Choroid plexus present throughout ventricles:
- CSF produced by choroid plexus
- Filters blood from branches of internal carotid and basilar arteries
- Choroid plexus present throughout ventricles:

Structure of the choroid plexus
- Very simple structure
- Capillary network surrounded by … epithelium
- During CSF production
- Blood filtered through … capillaries
- Components transported through … epithelium into ventricles
- Very simple structure
- Capillary network surrounded by cuboidal epithelium
-
During CSF production
- Blood filtered through fenestrated capillaries
- Components transported through cuboidal epithelium into ventricles

Structure of the choroid plexus


Cuboidal epithelium
- Specialized ependymal cells
- … present to increase SA
- Actively transport … components (or by facilitated diffusion)
- …directional (uptake of metabolites into circulatory system)
- Not all … produced by choroid plexus within ventricles
- …% from other sites within brain parenchyma
- Specialized ependymal cells
- Villi present to increase SA
- Actively transport CSF components (or by facilitated diffusion)
- Bidirectional (uptake of metabolites into circulatory system)
-
Not all CSF produced by choroid plexus within ventricles
- 40% from other sites within brain parenchyma

CSF composition
- CSF differs in composition compared to blood plasma - … protein in CSF compared to plasma
- Differences maintained by … transport process
- Very few cells (0-3 lymphocytes/cubic mm)
- CSF composition ideal for physiological functioning of neurons
- CSF differs in composition compared to blood plasma - lower protein in CSF compared to plasma
- Differences maintained by active transport process
- Very few cells (0-3 lymphocytes/cubic mm)
- CSF composition ideal for physiological functioning of neurons
*

More protein in plasma or CSF?
More in plasma - lower in CSF

CSF circulation within ventricles


CSF passes out of ventricles into the … space
CSF passes out of ventricles into the subarachnoid space
CSF circulation within subarachnoid space


Not much CSF passes through central canal - why?
Central canal is usually blocked in adults

Subarachnoid space
- Lies between … and …
- Subarachnoid space follows contours of brain
- CSF in contact with brain … - IMPORTANT
- Transfer of micronutrients into brain
- Removal of …
- Lies between pia and arachnoid
- Subarachnoid space follows contours of brain
- CSF in contact with brain parenchyma - IMPORTANT
- Transfer of micronutrients into brain
- Removal of metabolites

T2 weighted MRI - CSF appears…
white
Arachnoid granulations
- … of arachnoid membrane (villi) through dura mater into venous sinuses
- Mainly within the superior … and … venous sinuses
- Herniations of arachnoid membrane (villi) through dura mater into venous sinuses
- Mainly within the superior sagittal and transverse venous sinuses
*

Absorption of CSF
- CSF pressure in subarachnoid space … pressure in venous sinuses - in order for CSF to … through
- Prevents blood … in subarachnoid space
- In disease:
- If venous pressure … CSF pressure
- Tips of arachnoid … close off - act as …-way …
- CSF pressure in subarachnoid space exceeds pressure in venous sinuses - in order for CSF to move through
- Prevents blood pooling in subarachnoid space
-
In disease:
- If venous pressure exceeds CSF pressure
- Tips of arachnoid granulations close off - act as one-way valves
CSF volume
- … CSF produced per day (0.35 ml/min)
- Total volume in system = 90-140ml
- Normally quoted …
- 30 ml ventricles, 110 ml subarachnoid space
- Normally quoted …
- Continuously moving
- Excess absorbed by arachnoid …
- 500ml CSF produced per day (0.35 ml/min)
- Total volume in system = 90-140ml
- Normally quoted 140
- 30 ml ventricles, 110 ml subarachnoid space
- Normally quoted 140
- Continuously moving
- Excess absorbed by arachnoid granulations
Main functions of CSF
- CSF is functionally important
-
Lots of functions:
- Hydraulic buffer to cushion brain against …
- Vehicle for removal of … from CNS
- Stable … environment for neuronal function
- Transport of … and chemicals
- CSF is functionally important
-
Lots of functions:
- Hydraulic buffer to cushion brain against trauma
- Vehicle for removal of metabolites from CNS
- Stable ionic environment for neuronal function
- Transport of neurotransmitters and chemicals
Colour of CSF in disease
- CSF normally …, … fluid, but is discoloured in some pathological states:
- …/…/… (Xanthocromia)
- E.g. subarachnoid haemorrhage - Lysis of RBC, haemoglobin release
- …/…
- E.g. Bacterial meningitis - Leukocytes increased, Indicative of infection
- …/…/… (Xanthocromia)
- CSF normally clear, sterile fluid, but is discoloured in some pathological states:
- Yellow/Orange/Pink (Xanthocromia)
- E.g. subarachnoid haemorrhage - Lysis of RBC, haemoglobin release
- Cloudy/Turbid
- E.g. Bacterial meningitis - Leukocytes increased, Indicative of infection
- Yellow/Orange/Pink (Xanthocromia)
CSF is normally what colour?
clear - but discoloured in some pathological states

If CSF is cloudy/turbid…
indicates infection

If CSF is yellow/orange/pink (xanthocromia) it means…
lysis of RBC, haemoglobin release - e.g. in subarachnoid haemorrhage

CSF sampling - how?
- Taken by lumbar puncture
- At lumbar cistern - no spinal cord
CSF sampling
- Taken by … ..
- At lumbar cistern - no .. ..
-
Taken by lumbar puncture
- At lumbar cistern - no spinal cord

CSF sampling between L.. and L.. in adults
lumbar puncture - L3 and L4

Hydrocephalus
- Dilation of brain …
- Due to blocked … circulation, impaired absorption, or over secretion
- Increased intracranial (…) pressure
- … on surrounding tissues affects neurological function
- Symptoms include: headaches, vomiting, visual disturbances, papilledema (Swelling of optic disc), seizures, altered cognition, balance and coordination problems
- Can be congenital or …
- Dilation of brain ventricles
- Due to blocked CSF circulation, impaired absorption, or over secretion
- Increased intracranial (CSF) pressure
-
Pressure on surrounding tissues affects neurological function
- Symptoms include: headaches, vomiting, visual disturbances, papilledema (Swelling of optic disc), seizures, altered cognition, balance and coordination problems
- Can be congenital or acquired
Hydrocephalus
- … of brain ventricles
- Due to … CSF circulation, impaired …, or over …
- Increased … (CSF) …
- Pressure on surrounding tissues affects neurological function
- Symptoms include: headaches, vomiting, visual disturbances, papilledema (Swelling of optic disc), seizures, altered cognition, balance and coordination problems
- Can be … or acquired
- Dilation of brain ventricles
- Due to blocked CSF circulation, impaired absorption, or over secretion
- Increased intracranial (CSF) pressure
- Pressure on surrounding tissues affects neurological function
- Symptoms include: headaches, vomiting, visual disturbances, papilledema (Swelling of optic disc), seizures, altered cognition, balance and coordination problems
- Can be congenital or acquired
Symptoms of hydrocephalus:
Symptoms include: headaches, vomiting, visual disturbances, papilledema (Swelling of optic disc), seizures, altered cognition, balance and coordination problems
Non-communicating hydrocephalus
- … within the ventricular system
- Due to …, cyst, … (E.g. narrowing of cerebral aqueduct)
- CSF does not … over surface of brain
-
Blockage within the ventricular system
- Due to tumour, cyst, stenosis (E.g. narrowing of cerebral aqueduct)
- CSF does not circulate over surface of brain

Surgery for non-communicating hydrocephalus:
insert shunt to reduce intracranial pressure

What is Dandy-Walker syndrome?
- Type of non-communicating hydrocephaly - Congenital malformation of the cerebellum (1:30,000 births)
- Obstruction within foramina of fourth ventricle
- Symmetrical dilation of lateral, third and fourth ventricles
- In infancy, child’s head may become enlarged

Dandy-Walker syndrome
- Type of non-communicating hydrocephaly - … malformation of the cerebellum (1:30,000 births)
- Obstruction within foramina of … ventricle
- Symmetrical … of …, … and … ventricles
- In infancy, child’s head may become …
- Type of non-communicating hydrocephaly - Congenital malformation of the cerebellum (1:30,000 births)
- Obstruction within foramina of fourth ventricle
- Symmetrical dilation of lateral, third and fourth ventricles
- In infancy, child’s head may become enlarged

Communicating hydrocephalus
- Obstruction in the … villi
- Movement of CSF into … sinuses is impeded
- E.g. impaired absorption following subarachnoid …, trauma or bacterial …
- Obstruction in the arachnoid villi
-
Movement of CSF into venous sinuses is impeded
- E.g. impaired absorption following subarachnoid haemorrhage, trauma or bacterial meningitis

What is communicating hydrocephalus?
- Obstruction in the arachnoid villi
- Movement of CSF into venous sinuses is impeded
- E.g. impaired absorption following subarachnoid haemorrhage, trauma or bacterial meningitis