Question

Pia mater is-
(a)Innermost meninges
(b)Middle meninges
(c)Outer meninges
(d)None of the above

Answer 1

Hint: Meninges refers to the brain and spinal cord membranes. The dura mater, arachnoid mater, and pia mater are classified as three layers of meninges. Such coverings have two main functions: to provide the cerebral and cranial vasculature with a protective framework.

Complete answer:
The delicate innermost layer of the meninges is the pia mater. The thin fibrous tissue that surrounds the cerebrospinal fluid is impermeable to the fluid and provides protection for the other layers of the meninges. This serves as a brain buffer. It makes it possible to move through blood vessels and nourish the brain.
The function of the pia mater, along with the other meningeal layers, is to protect the central nervous system by containing the cerebrospinal fluid that cushions the brain and spine. The cranial pia mater covers the brain's surface.

Additional Information:
Dura mater is a thick membrane that surrounds the brain and spinal cord made of dense irregular connective tissue. It is the outermost of the three membrane layers which protect the central nervous system, called the meninges. The arachnoid substrate and the pia mater are the other two meningeal layers.
One of the three meninges, the protective membranes covering the brain and spinal cord, is the arachnoid mother. In the fetus, the arachnoid mater is a derivative of the neural crest mesectoderm.
So, the correct answer is ‘Innermost meninges’.

Note: There are structural and embryological variations between the brain and the spinal cord's meningeal coverings. Both the mesenchyme and the encephalic neural crest-derived from the encephalic meninges, while the paraxial mesenchyme originates from the meninges of the spine and caudal regions of the brain.