EVERYDAY SCIENCE

Detailed explanation-1: -Three layers of membranes known as meninges protect the brain and spinal cord. The delicate inner layer is the pia mater. The middle layer is the arachnoid, a web-like structure filled with fluid that cushions the brain. The tough outer layer is called the dura mater.

Detailed explanation-2: -The arachnoid sits between the dura and the pia and is an avascular membrane that is involved in cerebrospinal fluid (CSF) metabolism via the subarachnoid space.

Detailed explanation-3: -The space between the arachnoid and pia is called the subarachnoid space and it is filled with the cerebrospinal fluid (CSF).

Detailed explanation-4: -Meninges are formed by three tissue membranes that are primarily known as wrappers of the brain. They consist of dura mater, arachnoid and pia mater. The dura mater or pachymeninx (pachy-thick) is the outer membrane and forms a sac that envelops the other meningeal layers.

Detailed explanation-5: -The dura mater is composed of two layers: the periosteal/endosteal layer and the meningeal layer. The dural venous sinuses are between these two layers. The dura folds to form septa that create the falx cerebri, tentorium cerebelli, falx cerebelli, and diaphragma sellae.