Lect 21 - meninges and ventricular system

Flashcards covering the meninges, ventricular system, and cerebrospinal fluid.

What are the three layers of the meninges, which protect the brain?

Dura mater, arachnoid, and pia mater

What is the outermost layer of the meninges called, and what is it known for?

Dura mater, known as the 'tough mother', is dense and fibrous.

Where are venous sinuses formed within the dura mater?

In the space between the inner and outer layers of the dura mater.

What is the function of dural folds, and from which layer of the dura mater are they formed?

They separate major divisions of the brain and provide stability. They are formed from the inner layer of the dura mater.

Name the three dural folds and the brain regions they separate.

Falx cerebri (cerebral hemispheres), falx cerebelli (cerebellar hemispheres), tentorium cerebelli (cerebrum from cerebellum)

What two things are collected in the venous sinuses?

Venous blood from the brain and ‘old’ CSF.

Why is the arachnoid layer named as such, and where is it located?

It has a spider-like appearance due to lots of blood vessels. It's located beneath the dura mater and above the pia mater.

What is a key structural feature that the arachnoid layer lacks?

It does not extend into sulci (valleys).

Name three special features of the arachnoid layer.

Subarachnoid space, arachnoid granulations, arachnoid trabeculae

What structural component connects the arachnoid and pia mater?

Arachnoid trabeculae

What fluid fills the subarachnoid space, and how is the outer layer of the arachnoid bound?

Cerebrospinal fluid (CSF); the outer layer is bound with tight junctions.

What is the function of arachnoid granulations?

Transport ‘old’ CSF from the subarachnoid space into the venous sinus.

What is the innermost layer of the meninges, and what are its characteristics?

Pia mater, known as the 'delicate mother', is transparent and delicate.

How does the pia mater differ in its adherence to the brain compared to the arachnoid?

The pia mater adheres to the brain and follows gyri and extends into sulci, while the arachnoid does not extend into sulci.

What is the ventricular system?

Network of interconnected ‘spaces’ within the brain

What type of cells line the spaces in the ventricular system and what is their function?

Ependymal cells; they circulate the CSF (waving cilia).

Name the ventricles of the ventricular system and their locations.

Lateral ventricles (2, in each cerebral hemisphere), third ventricle (1, in diencephalon), cerebral aqueduct (1, in midbrain), fourth ventricle (1, at the level of the cerebellum)

Where is the cerebral aqueduct located, and what ventricles does it connect?

Located in the midbrain, it connects the 3rd ventricle to the 4th ventricle.

Where is CSF produced and what are its functions?

Produced by the choroid plexus within the ventricles; provides support and cushion, and transports nutrients and waste.

What cells make up the blood/CSF barrier within the choroid plexus?

Epithelial cells.

List the circulation path of CSF starting from the lateral ventricles.

Lateral ventricles → 3rd ventricle → cerebral aqueduct → 4th ventricle → subarachnoid space.

Where does CSF exit to after circulating within the subarachnoid space?

Through arachnoid granulations into the venous sinus.