Search results
Results from the WOW.Com Content Network
The arachnoid mater covering the brain is referred to as the arachnoidea encephali, and the portion covering the spinal cord as the arachnoidea spinalis. The arachnoid and pia mater are sometimes considered as a single structure, the leptomeninx, or the plural version, leptomeninges (lepto, from the Greek root meaning "thin" or "slender").
The middle element of the meninges is the arachnoid mater, or arachnoid membrane, so named because of its resemblance to a spider web. It cushions the central nervous system. This thin, transparent membrane is composed of fibrous tissue and, like the pia mater, has an outer layer of tightly packed flat cells, forming the arachnoid barrier. [8]
Arachnoid granulations (also arachnoid villi, and pacchionian granulations or bodies) are small outpouchings of the arachnoid mater and subarachnoid space into the dural venous sinuses of the brain. The granulations are thought to mediate the draining of cerebrospinal fluid (CSF) from the subarachnoid space into the venous system .
The anatomy of spiders includes many characteristics shared with other arachnids. These characteristics include bodies divided into two tagmata (sections or segments), eight jointed legs, no wings or antennae, the presence of chelicerae and pedipalps , simple eyes , and an exoskeleton , which is periodically shed .
This results in fluid-filled cavities with random spacing and size. The mesenchymal material between these cavities is the origin of the arachnoid trabeculae. The upper and lower surfaces of the layer become the arachnoid and pia mater membranes, to which the trabecular structure remains attached.
Arachnoid (astrogeology), a geological structure found only on the planet Venus; Arachnoid (botany), referring to organs with a cobwebby exterior appearance; Arachnoid granulation, small protrusions of the arachnoid mater; Arachnoid mater, a layer of the meninges, membranes that contain the central nervous system
The pia firmly adheres to the surface of the brain and loosely connects to the arachnoid layer. [6] Because of this continuum, the layers are often referred to as the pia arachnoid or leptomeninges. A subarachnoid space exists between the arachnoid layer and the pia, into which the choroid plexus releases and maintains the cerebrospinal fluid ...
Between the arachnoid mater and the pia mater is the subarachnoid space and subarachnoid cisterns, which contain the cerebrospinal fluid. [11] The outermost membrane of the cerebral cortex is the basement membrane of the pia mater called the glia limitans and is an important part of the blood–brain barrier. [12]