Question

Give function of meninges and CSF.

Answer 1

Hint: Protective covering of the brain is known as meninges. CSF stands for cerebrospinal fluid and is present in subarachnoid space. The choroid plexus responsible is a network of loose connective tissue of pia mater that secrets this fluid.

Complete answer:
The brain is surrounded by three protective layers of connective tissue along with the cranium. They are:-
> Dura mater: It is the outermost covering of the brain. It is usually thick,tough and encircles the cranial cavity. Its surface is covered with simple squamous epithelium. The space present between the dura mater and the arachnoid membrane is known as subdural space. It does contain a fluid.
> Arachnoid mater: It is the middle layer. It is a very thin layer and non- vascular. The space present between the pia mater and the arachnoid membrane is called subarachnoid space. This space is filled with cerebrospinal fluid.
> Pia mater : It is the innermost layer. It is thin and highly vascular and is in close association with the brain. It is covered by simple squamous epithelium.

CSF: The cerebrospinal fluid is lymph-like fluid present in the ventricles of the brain. This fluid is secreted by the choroid plexus at the time of filtration of blood. It is alkaline in nature and serves are carious following functions:
> Acts as a shock-proof cushion for the brain and the spinal cord.
> It also acts as a medium for exchange of respiratory gases, food, waste products.
> It also maintains constant pressure inside the cranium.

Note:
CSF acts as a blood brain barrier as it keeps check on the passage of ions and molecules passing from blood to the brain. It serves the function of preventing the brain and spinal cord from drying.