Ventricular System Flashcards
How many ventricles are there?
Four
(2 lateral, third, fourth)
Where are the lateral ventricles located?
In the cerebral hemispheres
Where is the third ventricle located?
By thalamus and hypothalamus
Where is the fourth ventricle located?
Located by pons, medulla oblongata, and cerebellum
Which embryonic structure do the lateral ventricles originate from?
Telencephalon
Which embryonic structure does the third ventricle originate from?
Diencephalon
Which embryonic structure does the fourth ventricle originate from?
Metencephalon
Which embryonic structure does the cerebral aqueduct develop from?
Mesencephalon
How do the ventricles develop from embryonic layers?
Outpouches form
Do the lateral ventricles communicate with each other?
No
Do the lateral ventricles communicate with the third ventricle?
Yes
How do the lateral and third ventricles communicate?
Via the interventricular foramen of Monro
What are the three horns of the lateral ventricles?
Anterior, posterior, and inferior horns
What structure forms the roof of the lateral ventricles?
Corpus callosum
What structure forms the floor of the lateral ventricles?
Caudate nucleus
What structure forms the lateral walls of the lateral ventricles?
Thalamus
What does the septum pellucidum do?
Separates the lateral ventricles
What structure forms the medial wall separating the lateral ventricles?
Septum pellucidum
Which structure creates CSF?
Choroid plexus
Where is the choroid plexus found in the lateral ventricles?
Body of the ventricle
What cell type creates CSF?
Ependymal cells
What structure connects the third and fourth ventricles?
Cerebral aqueduct of Sylvius
Which brain structures is the third ventricle bounded by?
Thalamus and hypothalamus
What is the fourth ventricle continuous with?
The central canal of the spinal cord
Between which brain structures is the fourth ventricle located?
Posterior to the medulla oblongata and pons, anterior to cerebellum
How many openings does the fourth ventricle have?
Three foramina
2x Luschka
1x Magendie
What are the foramina of the fourth ventricle?
2x Luschka - lateral
1x Magendie - posterior
What structure is at the inferior end of the central canal?
Terminal ventricle
What does CSF contain?
Inorganic salts, glucose, trace proteins, lymphocytes
At what pressure is CSF maintained at?
8-15mmHg
What is the total volume of CSF?
135-150mls
How often is CSF recycled in the brain?
4 times a day
What volume of CSF is produced each day?
Around 500mls
What are the four functions of CSF?
Protection via buffering brain
Buoyancy via reducing net weight of brain and relieving pressure at base of brain
Removal of waste products from CSF to blood
Endocrine functions via transport of hormones
Where is CSF produced?
In choroid plexus in the ventricles
Where is the majority of CSF drained?
Via arachnoid granulations in superior sagittal sinus
What structure stops the backflow of blood into ventricular system?
Arachnoid villi act as one way valves
How does pressure influence the flow of CSF?
If CSF pressure is greater than venous pressure so CSF flows into bloodstream and not the other way round.
If venous pressure is greater than CSF pressure, blood would flow into ventricular system however arachnoid villi prevent this
What is hydrocephalus?
Overproduction of CSF
What are the two subtypes of hydrocephalus?
Communicating (defective absorption)
Non communicating (obstruction)
What are the four potential causes of hydrocephalus?
Overproduction of CSF
Defective absorption of CSF
Venous drainage insufficiency
Obstruction in ventricular system
In communicating hydrocephalus, what is the most likely cause for the condition?
Defective absorption of CSF
In communicating hydrocephalus, what is the rarest cause for the condition?
CSF overproduction
In communicating hydrocephalus, what is an unusual cause for the condition?
Venous drainage insufficiency
What is the treatment for hydrocephalus?
Depends on cause
Surgical interventions include resection of obstruction and/or insertion of a shunt to redirect CSF to a blood vessel or the abdomen
