germinal epithelium

germinal epithelium

n.

See surface epithelium.

---

germinal epithelium,

1 the epithelial layer covering the genital ridge from which the gonads are derived in early embryonic development.

2 the epithelial covering of the ovary, formerly thought to be the site of the formation of the oogonia. See also oogenesis.

---

epithelium [ep″ĭ-the´le-um] (pl. epithe´lia) (Gr.)

the cellular covering of internal and external surfaces of the body, including the lining of vessels and other small cavities. It consists of cells joined by small amounts of cementing substances. Epithelium is classified into types on the basis of the number of layers deep and the shape of the superficial cells.

ciliated epithelium epithelium bearing vibratile, hairlike processes (cilia) on its free surface.

columnar epithelium epithelium whose cells are of much greater height than width.

cuboidal epithelium epithelium whose cells are of approximately the same height and width, and appear square in transverse section.

germinal epithelium thickened peritoneal epithelium covering the gonad from earliest development; formerly thought to give rise to germ cells.

glandular epithelium that composed of secreting cells.

pigmentary epithelium (pigmented epithelium) that made of cells containing granules of pigment.

sense epithelium (sensory epithelium) neuroepithelium (def. 1).

simple epithelium that composed of a single layer of cells.

squamous epithelium that composed of flattened platelike cells.

stratified epithelium epithelium made up of cells arranged in layers.

transitional epithelium a type characteristically found lining hollow organs, such as the urinary bladder, that are subject to great mechanical change due to contraction and distention; originally thought to represent a transition between stratified squamous and columnar epithelium.

---

epithelium

pl. epithelia [Gr.] the cellular covering of internal and external surfaces of the body, including the lining of vessels and other small cavities. It consists of cells joined by small amounts of cementing substances. Epithelium is classified into types on the basis of the number of layers deep and the shape of the superficial cells. Standard classifications include ciliated (cilia attached), columnar (taller than wide), cuboidal (same height as width), pseudostratified (single layer but because of varying cell height appears to be more than one), simple (one cell layer), squamous (flattened, plate-like cells), stratified (more than one layer), transitional (variable number of layers apparent). Other types are listed below.

---

anterior epithelium

the thin layer of stratified squamous cells that form the outermost layer of the cornea.

corneal epithelium

see anterior epithelium (above).

germinal epithelium

thickened peritoneal epithelium covering the gonad from earliest development; formerly thought to give rise to germ cells.

glandular epithelium

that composed of secreting cells.

lens epithelium

cuboidal epithelium covering the lens.

pigmentary epithelium, pigmented epithelium

that made of cells containing granules of pigment.

posterior epithelium

the single layer of epithelial cells on the back of the cornea, between stroma and aqueous humour; the corneal endothelium.

retinal pigment epithelium

see retina.

sense epithelium, sensory epithelium

see neuroepithelium (1).