Nervous part 4

Meninges

The three connective tissue membranes covering and protecting the CNS structures

Dura mater

Outermost layer of the meninges. It is a double-layered membrane surrounding the brain, with one of its layers forming the periosteum and the other forming the outermost covering of the brain

Meningeal layer

Layer of the dura mater that forms the outermost covering of the brain and continues as the dura mater of the spinal cord

Falx cerebri

Inner dural membrane fold that separates the two cerebral hemispheres

Tentorium cerebelli

Inner dural membrane fold that separates the cerebral hemispheres from the cerebellum

Arachnoid mater

The middle meningeal layer that have threadlike extensions span the subarachnoid space to attach it to the innermost membrane

Arachnoid granulations

Specialized projections of the arachnoid mater that protrude through the dura mater. Through these, CSF is absorbed into the venous blood in the dural sinuses

Subarachnoid space

Space in the meninges filled with CSF

Pia mater

Innermost membrane of the meninges. It is delicate and clings tightly to the surface of the brain and spinal cord, following every fold

Meningitis

Inflammation of the meninges

Encephalitis

Inflammation of the brain

Cerebrospinal fluid (CSF)

Is a watery "broth" similar to plasma and formed in the choroid plexus. It forms a watery cushion that protects the fragile nervous tissue from blows and other trauma, and helps the brain "float" so it is not damaged by the pressure of its own weight.

Hydrocephalus

CSF accumulation and exertion of pressure on the brain

Blood-brain barrier

Composed of the least permeable capillaries in the body, only letting water, glucose, and essential amino acids to pass

Spinal cord

Is a glistening white continuation of the brain stem and provides a two-way conduction pathway to and from the brain. It is also the major reflex center

Cauda equina

Collection of spinal nerves at the inferior end of the vertebral canal

Dorsal horns

Posterior projection of the spinal cord gray matter that contains interneurons

Dorsal root ganglion

Where the cell bodies of sensory neurons are found

Ventral horns

Posterior projection of the spinal cord gray matter that contain cell bodies of motor neurons of the somatic nervous system

Spinal nerves

The fusion of ventral and dorsal roots of the spinal cord gray matter

White matter of the spinal cord

Composed of myelinated fiber tracts—some running to higher centers, some traveling from the brain to the cord, and some conducting impulses from one side of the spinal cord to the other