agyhártyákra

Agyhártyákra, commonly referred to as meninges in English, are the three protective membranes that cover the brain and spinal cord of vertebrates. These membranes are the dura mater, the arachnoid mater, and the pia mater, arranged from outermost to innermost.

The dura mater is the tough, fibrous outer layer. It is a thick, inelastic membrane that provides robust protection against physical trauma. It adheres closely to the inner surface of the skull and forms dural folds that compartmentalize the cranial cavity, preventing excessive movement of the brain.

Beneath the dura mater lies the arachnoid mater, a delicate, web-like membrane. The space between the arachnoid mater and the dura mater is called the subdural space, which can fill with fluid or blood in certain pathological conditions.

The innermost layer is the pia mater, a thin, highly vascularized membrane that directly adheres to the surface of the brain and spinal cord, following all of its gyri and sulci. Blood vessels within the pia mater supply nutrients and oxygen to the nervous tissue.

The space between the arachnoid mater and the pia mater is known as the subarachnoid space. This space is filled with cerebrospinal fluid (CSF), which acts as a cushion, absorbing shock and protecting the central nervous system from damage. CSF also circulates nutrients and removes waste products. Inflammation of the meninges is called meningitis, a serious condition that can be caused by infections.