layer
(lā'ĕr 
)
A thin sheetlike structure of more or less uniform thickness.
SEE: stratum.
bacillary l.The rod and cone layer of the retina.
basal l.The outermost layer of the uterine endometrium lying next to the myometrium. SYN: basilar layer.
SEE: Bernard gland ular layer.
choriocapillary l.Lamina choriocapillaris.
claustral l.The layer of gray matter between the external capsule and insula.
clear l.The stratum lucidum of the epidermis.
SEE: stratum lucidum.
columnar l.A layer of tall, narrow epithelial cells forming a covering or lining.
compact l.The dense surface layer of the uterine endometrium.
cuticular l. of epithelium A layer of dense cytoplasm at the luminal end of some epithelial cells, esp. the layer at the surface of columnar epithelium of the intestine.
enamel l.The innermost layer the enamel organ. SYN: ameloblastic layer.
SEE: enamel organ.
ependymal l.The inner layer of cells of the embryonic neural tube.
feeder l.A layer of connective tissue cells that are used to nourish cultured tissue cells in the laboratory. The feeder cell layer is often derived from mouse fibroblasts. Feeder cells supply metabolites to the cells they support, do not grow or divide, and can be inactivated by gamma irradiation.
functional l.The portion of the endometrium adjacent to the uterine cavity. After it is shed in menstruation, it is regenerated by the basal layer.
SEE: basal layer.
ganglionic l.1The fifth layer of the cerebral cortex.2The inner layer of ganglion cells in the retina whose axons form the fibers of the optic nerve.
germ l.Any of the three primary layers of the developing embryo from which the various organ systems develop.
SEE: ectoderm; endoderm; mesoderm.
germinative l.The deepest layer of the epidermis, consisting of a basal layer of keratinocytes. SYN: malpighian layer; stratum germinativum.
granular exterior l.The second layer of the cerebral cortex, consisting of pyramidal cells.
granular interior l.The fourth layer of the cerebral cortex, consisting principally of closely packed stellate cells.
ABBR: HVL
The amount of lead, copper, cement, or other material that would dissipate a beam of radiation by 50%. The number of half-value layers required for safety in blocking the area on a patient is five, because that represents 50% of 50% and 50% of that, and so forth. For example, 50% + 25% + 12.5% + 6.23% + 3.12% = 96.9%. Thus the patient would be shielded from all but about 3% of the radiation. (Examples of the thickness of material required to protect from radiation are 2 in [5 cm] of lead or 2 ft [61 cm] of cement.)SEE: under Henle, Friedrich G. J..
SEE: under Huxley, Thomas H..
SEE: Langhans layer.
malpighian l.Germinative layer.
mantle l.The middle layer of the neural tube of the developing embryo.
molecular l.1The outermost layer of the cerebral or cerebellar cortex.2The inner or outer plexiform layer of the retina.
molecular l. of the cerebral cortex The most superficial layer of the cortex of the brain, consisting of outer stellate cells and granule cells.
mucus l.A thick, slippery coating of glycoproteins and other secreted organic chemicals that line and protect the intestinal epithelium. SYN: mucus barrier.
nervous l.The portion of the retina that contains the nerves
odontoblastic l.The layer of connective tissue cells at the outer edge of the pulp where the cells produce the dentin of the tooth.
SEE: under Ollier, Louis Xavier Edouard.
osteogenic l.The inner layer of the periosteum. It contains osteoblasts that become active during repair of fractures. SYN: Ollier layer.
outer nuclear l.The layer of the retina containing the nuclei of the visual receptor cells, the rods, and cones.
papillary l.The superficial layer of the dermis lying immediately under the epidermis into which it extends, forming dermal papillae. SYN: stratum papillare.
pigment l.The outermost layer of the retina. Cells contain the pigment fuscin.
SEE: fuscin; layer of rods and cones.
SEE: Purkinje layer.
reticular l.The inner layer of the dermis lying beneath the papillary layer.
l. of rods and cones The layer of the retina of the eye next to the pigment layer. It contains the rods and cones.
SEE: pigment layer.
somatic l.In the embryo, a layer of extraembryonic mesoderm that forms a part of the somatopleure.
SEE: somatopleure.
spinous l.The layer between the granular and basal layers of the skin. Prickle cells are present in this layer. SYN: prickle cell layer; stratum spinosum.
SEE: stratum malpighii.
splanchnic l.In the embryo, a layer of extraembryonic mesoderm that with the endoderm forms the splanchnopleure.
spongy l.The middle layer of the uterine endometrium, containing dilated portions of uterine gland s. SYN: stratum spongiosum.
subendocardial l.The layer of loose connective tissue between the endocardium and the myocardium.
subendothelial l.The layer of fine fibers and fibroblasts lying immediately under the endothelium of the tunica intima of larger arteries and veins.
subodontoblastic l.A relatively cell-free zone just below the odontoblastic layer in the dental pulp. SYN: Weil basal layer.
Tomes granular l.The layer of interglobular dentin beneath the dentinocemental junction in the root of a tooth.