meninges

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meninges

(mĭnĭn`jēz), three membranous layers of connective tissueconnective tissue,
supportive tissue widely distributed in the body, characterized by large amounts of intercellular substance and relatively few cells. The intercellular material, or matrix, is produced by the cells and gives the tissue its particular character.
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 that envelop the brain and spinal cord (see nervous systemnervous system,
network of specialized tissue that controls actions and reactions of the body and its adjustment to the environment. Virtually all members of the animal kingdom have at least a rudimentary nervous system.
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). The outermost layer, or dura mater, is extremely tough and is fused with the membranous lining of the skull. In the brain it forms a vertical sheet that separates the cerebral hemispheres and a horizontal sheet that lies between the cerebrum and the cerebellum. The thin arachnoid membrane lies below and in close contact with the dura mater. The innermost layer, or pia mater, is in direct contact with the brain and spinal cord and contains the blood vessels that supply them. The pia mater and arachnoid membrane are separated by the subarachnoid space containing the cerebrospinal fluid, which carries nutrients, absorbs the impact of shocks, and acts as a barrier to disease organisms. Thus, the meninges provide a fluid-filled jacket for the protection of neural tissues and allow for the flexing and twisting of the vertebral column about the spinal cord.

Meninges

 

the connective-tissue membranes enveloping the brain and spinal cord in vertebrates and man.

A primitive meninx develops in the embryo and differentiates into dura mater (adjoining the periosteum) and primary pia mater (adjoining the brain and forming the folds of the brain’s vascular plexuses). Three meninges are distinguished in adult mammals and man. In the brain region, dura mater, the outer membrane, forms the periosteum of the inner surface of the skull and passes longitudinal and transverse processes into the cranial cavity. The principal processes are the falciform, wedged between the two cerebral hemispheres (a rudiment is found in birds), and the tentorium cerebelli, which separates the cerebellum from the lower surface of the occipital lobes of the cerebrum. Sinuses form, when the dura mater splits, in certain places in the cranium; venous blood flows into them from the brain. In the spinal cord region, the dura mater consists of two layers, outer (periosteum) and inner. These are divided by the epidural space, which is filled with adipose tissue and venous plexuses.

The primitive pia mater in mammals splits into arachnoid and vascular or secondary, meninges. The arachnoid is internal to the dura mater. In the cranial cavity, it adjoins the surface of the gyri of the cerebral cortex, without entering the sulci or other depressions (thereby forming cisternae). In the spinal cord region, the arachnoid adheres firmly to the inner layer of the dura mater.

The innermost of the membranes is the meninx vasculosa, which adheres to the surface of the spinal cord and brain and extends into the brain’s sulci and depressions, containing the blood vessels that feed the brain. The subarachnoid space, between the arachnoid and the meninx vasculosa, is filled with cerebrospinal fluid. The arachnoid and the meninx vasculosa, which join near the cerebral cortex, are given the common name of “pia mater.”

meninges

[mə′nin·jēz]
(anatomy)
The membranes that cover the brain and spinal cord; there are three in mammals and one or two in submammalian forms
References in periodicals archive ?
In study on Meninges surrounding the cerebellum in the treatment group compared with the normal state of control group meningeal tissue, pia matter was observed as hyperemia and edematous (fig 3,4).
3] However, it is not anatomically restricted to the chest cavity and has been described in various extrapleural sites, such as upper respiratory system, lung, liver, nasal cavity, paranasal sinuses, mammary glands, orbita, mediastinum, greater salivary glands, meninges, and even the kidney.
Meningitis is a relatively rare infection that affects the delicate membranes -- meninges -- that cover the brain and spinal cord.
Mair began chemotherapy again, but started to suffer from migraines and feeling unwell, it discovered that the cancer had spread to the meninges lining of the brain and was untreatable She passed away peacefully surrounded by her family on 6 December 2012.
com/prnh/20130307/600769 Meningococcal disease caused by the bacterium Neisseria meningitidis is a life threatening condition which severely infects the meninges or the thin lining surrounding the brain and the spinal cord.
The meninges is the collective name for the three membranes that envelop the brain and spinal cord.
Moreover, the tegmen mastoideum was destroyed and the meninges of the right temporal lobe and cerebellum were thickened and enhanced by contrast.
A highly infectious bacterial infection that most commonly affects the lungs, but can also affect the kidneys, the meninges (the protective coverings of the brain), joints, bones and pelvis if it is long term.
The deposition of GAGs in the meninges impairs the function of arachnoid granulations, leading to abnormal CSF reabsorption.
Ali has been diagnosed with meningocele -- a protrusion of the meninges through an opening in the spinal column, forming a bulge filled with cerebrospinal fluid.
Wei's son, Xiao Wei, suffers from myelomeningocele, a more severe form of spina bifida in which the meninges and spinal cord become herniated.
These membranes are called the meninges and help protect the brain from injury and infection.