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substance; used in anatomic nomenclature in naming various components of body tissues or structures.
substantia al´ba white matter.
substantia gelatino´sa the substance sheathing the posterior horn of the spinal cord and lining its central canal.
substantia gri´sea gray matter.
substantia ni´gra a dark layer of gray matter separating the tegmentum of the midbrain from the crus cerebri.
those regions of the brain and spinal cord that are largely or entirely composed of nerve fibers and contain few or no neuronal cell bodies or dendrites.
Etymology: L, substantia, essence, albus, white
the part of the central nervous system that is enclosed in myelin sheaths. The myelin contributes a white coloring to otherwise gray nerve tissue.
substantia alba; white matter central nervous system regions containing large amounts of myelin with few/no nerve cell bodies; e.g. spinal tracts with myelinated nerve fibres
pl. substantiae [L.] substance.
the white matter of the spinal cord and the brain.
the substance sheathing the posterior horn of the spinal cord and lining its central canal.
the gray matter of the spinal cord and brain.
substantia grisea centralis
the central gray matter that surrounds the cerebral aqueduct.
the layer of gray substance separating the tegmentum of the midbrain from the crus cerebri.
substantia propria corneae
layer of transparent lamellated fibrous connective tissue which constitutes the bulk of the cornea; composed of collagen fibers disposed in platelike formations, fibroblasts and ground substance with many nerve fibers but no blood vessels.
substantia propria choroid
loose connective tissue of the choroid.