| 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) |
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| blastodermic disk | The aggregation of blastomeres of a telolecithal ovum after cleavage has occurred. (05 Mar 2000) |
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| blastodermic ectoderm | External layer of the blastula. (05 Mar 2000) |
| blastodermic vesicle | In mammalian development, cleavage produces a thin walled hollow sphere, whose wall is the trophoblast, with the embryo proper being represented by a mass of cells at one side. The blastocyst is formed before implantation and is equivalent to the blastula. (18 Nov 1997) |
| 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) |