Q.What are the three protective coverings of the brain ?

The brain is enclosed by three protective connective-tissue membranes called meninges — the duramater (outermost), arachnoid mater (middle), and piamater (innermost) — which together protect the brain and, with the cerebrospinal fluid between them, cushion it against mechanical shock.

The three meninges, from outermost to innermost, are:

1. Duramater — the outermost, thickest, and toughest of the three layers, made of dense fibrous connective tissue; it lies just beneath the skull bone and provides strong mechanical protection to the brain.

2. Arachnoid mater — the middle layer, a thin, delicate, web-like (cobweb-like) membrane. Between the arachnoid mater and the piamater lies the subarachnoid space, which is filled with cerebrospinal fluid (CSF); this fluid cushions the brain and absorbs mechanical shocks.

3. Piamater — the innermost layer, a thin, delicate membrane that is richly supplied with blood vessels and closely follows and adheres to every fold and contour of the brain's surface, helping supply it with nutrients and oxygen.

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