substantia(redirected from Ousia)
Also found in: Wikipedia.
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.
[L. substantia, essence, material, fr. sub- sto, to stand under, be present]
substantia/sub·stan·tia/ (sub-stan´shah) pl. substan´tiae [L.] substance.
substantia al´ba the white nervous tissue, constituting the conducting portion of the brain and spinal cord, composed mostly of myelinated nerve fibers.
substantia ferrugi´nea locus caeruleus.
substantia gelatino´sa the gelatinous-appearing cap forming the dorsal part of the posterior horn of the spinal cord.
substantia gri´sea gray substance; the gray nervous tissue composed of nerve cell bodies, unmyelinated nerve fibers, and supportive tissue.
substantia ni´gra the layer of gray substance separating the tegmentum of the midbrain from the crus cerebri.
1. the tough, fibrous, transparent main part of the cornea, between Bowman's membrane and Descemet's membrane.
2. the main part of the sclera, between the episcleral lamina and the lamina fusca.
[L. substantia, essence, material, fr. sub-sto, to stand under, be present]
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.