| blastodermic layers | The primordial cell layer's on the yolk surface of a telolecithal egg; in the earliest stages they consist of protoderm, and they later differentiate into ectoderm, endoderm, and mesoderm. (05 Mar 2000) |
|---|---|
| germ layers | The three layers of cells comprising the early embryo. (12 Dec 1998) |
| medullary layers of thalamus | Layers of myelinated fibres that appear on transverse sections of the thalamus; the lamina medullaris externa marks the ventral and lateral borders of the thalamus and delimits it from the subthalamus and reticular nucleus of thalamus; the lamina medullaris interna is interposed between the mediodorsal and ventral nuclei of the thalamus and encloses the intralaminar nuclei (centromedian, paracentral, and central lateral nuclei). Synonym: laminae medullares thalami, medullary layers of thalamus. (05 Mar 2000) |
| granular layers of cerebral cortex | Layers 2 (outer) and 4 (inner) of the cortex cerebri. (05 Mar 2000) |
| granular layers of retina | The outer nuclear layer, layer 4, of the retina, neuroepithelial layer of retina, and the inner layer, layer 6, of the retina, ganglionic layer of retina. Synonym: granular layers of retina, stratum nucleare externum et internum retinae. (05 Mar 2000) |
| circular layers of muscular tunics | The inner, circular layer of the smooth muscle of the muscular coat. Nomina Anatomica lists circular layers of muscular coats (stratum circulare tunicae muscularis...) of the following: 1) colon (... Coli ); 2) rectum (... Recti ); 3) small intestine (... Intestini tenuis ); 4) stomach (... Gastrici ). Synonym: stratum circulare tunicae muscularis gastricae, stratum circulare tunicae. (05 Mar 2000) |
| molecular layers of olfactory bulb | The layer's, composed mainly of nerve fibres, on the outer and inner sides of the layer of mitral cells of the bulb. (05 Mar 2000) |
| plexiform layers of retina | Layer's of the retina where synapses occur; in the external layer, processes of rods and cones synapse with bipolar neuron dendrites; in the internal layer, axon terminals of bipolar cells synapse with ganglion cell dendrites. See: retina. Synonym: stratum plexiforme externum et internum retinae. (05 Mar 2000) |
| nuclear layers of retina | The outer nuclear layer, layer 4, of the retina, neuroepithelial layer of retina, and the inner layer, layer 6, of the retina, ganglionic layer of retina. Synonym: granular layers of retina, stratum nucleare externum et internum retinae. (05 Mar 2000) |
| elastic layers of arteries | elastic laminae of arteries |
| elastic layers of cornea | See: anterior limiting layer of cornea, posterior limiting layer of cornea. (05 Mar 2000) |
| epithelial layers | See: epithelium. (05 Mar 2000) |
| layers of cerebellar cortex | The thin gray surface layer of the cerebellum, consisting of an outer molecular layer or stratum moleculare, a single layer of Purkinje cells (the ganglionic layer), and an inner granular layer or stratum granulosum. Synonym: cortex cerebelli. (05 Mar 2000) |
| layers of cerebral cortex | The outer portion of the brain, consisting of layersof nerve cells and the pathways that connect them. The cerebralcortex is the part of the brain in which thought processes take place.In Alzheimer's disease, nerve cells in the cerebral cortex die. (22 May 1997) |
| layers of retina | Light sensitive layer of the eye. In vertebrates, looking from outside, there are four major cell layers: (i) the outer neural retina, which contains neurons (ganglion cells, amacrine cells, bipolar cells) as well as blood vessels, (ii) the photoreceptor layer, a single layer of rods and cones, (iii) the pigmented retinal epithelium (PRE or RPE), (iv) the choroid, composed of connective tissue, fibroblasts and including a well vascularised layer, the chorio capillaris, underlying the basal lamina of the PRE. Behind the choroid is the sclera, a thick organ capsule. In molluscs (especially cephalopods such as the squid) the retina has the light sensitive cells as the outer layer with the neural and supporting tissues below. See: retinal rods, retinal cones, rhodopsin. (18 Nov 1997) |