Question

Which of the following forms the cerebrospinal fluid?
A. Choroid plexus
B. Dura mater
C. Arachnoid mater
D. Cerebrum and spinal cord

Answer 1

Hint: The space between the dura mater and the arachnoid is known as the subdural space, and the space between the arachnoid and the rash is known as the subarachnoid space. The spaces around the brain and its cavity are filled with a lymphatic fluid called cerebrospinal fluid (CSF). The spinal cord also contains cerebrospinal fluid.

Complete answer:
 Let’s first understand about all the options given above
The brain is surrounded by three membranes called Meninges these are Dura mater, Arachnoid mater and pia mater.
The outer dura mater is the hard, white membrane under the skull.
Intermediate arachnoid layer with fibrous tissue.
Thin transparent pia mater is situated close to the surface of the brain and spinal cord. In both places, the pia mater merges with the thin dorsal surface of the brain, forming the choroid plexus.
 The meninges protect the brain from external vibrations.
The choroid plexus (CP) is a major source of cerebrospinal fluid (CSF), which acts as a fluid cushion and disposal site for nervous system waste in vertebrates. CSF is mainly, but not exclusively, excreted by the choroid. Cerebral interstitial fluid, ependyma, and capillaries can also play an obscure role in cerebrospinal fluid secretion.
Hence, from the above points it’s clear that the correct option is Choroid plexus (A).

Note:
Cerebrospinal fluid (CSF) protects our central nervous system (CNS)from external shock. It helps in the exchange of nutrients and waste products between nerve tissue and blood, and also maintains constant pressure inside and outside the brain. The brain is made up of two types of nerve tissue: gray matter on the outside and white matter on the inside. The first consists of non-fixed neurons, and the second consists of medullary neurons. The brain, or brain, is a two-sided, symmetrical white structure.