Coelomic epithelium refers to the
epithelium
Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...
that lines the surface of the body wall and
abdominal
The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...
organs. It constitutes the outermost layer of the male and female
gonad
A gonad, sex gland, or reproductive gland is a Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gon ...
s, thus forming the
germinal epithelium of the female or
of the male. It is also called the germinal epithelium of Waldeyer or sometimes the superficial epithelial cells in
embryology
Embryology (from Ancient Greek, Greek ἔμβρυον, ''embryon'', "the unborn, embryo"; and -λογία, ''-logy, -logia'') is the branch of animal biology that studies the Prenatal development (biology), prenatal development of gametes (sex ...
. It is often encountered in the medical setting as an important source of various types of
ovarian cancer
Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different ...
, primary peritoneal serous cancer and
endometriosis
Endometriosis is a disease in which Tissue (biology), tissue similar to the endometrium, the lining of the uterus, grows in other places in the body, outside the uterus. It occurs in women and a limited number of other female mammals. Endomet ...
(coelomic metaplasia). ,
During gonadal
sex
Sex is the biological trait that determines whether a sexually reproducing organism produces male or female gametes. During sexual reproduction, a male and a female gamete fuse to form a zygote, which develops into an offspring that inheri ...
development, the coelomic epithelium, additionally with germ cells and mesenchymal cells make the indifferent gonad. As the coelomic epithelium is confronted with XY chromosomes, they will differentiate into
sertoli cells
Sertoli cells are a type of sustentacular "nurse" cell found in human testes which contribute to the process of spermatogenesis (the production of sperm) as a structural component of the seminiferous tubules. They are activated by follicle-sti ...
, which subsequently produce anti-Müllerian hormone, leading to the regression of the Müllerian duct. As the coelomic epithelium is confronted with XX chromosomes, the cells will differentiate into granulosa cells, which will not produce anti-Müllerian hormone and thus allow the development of the Müllerian duct.
The coelomic metaplasia theory provides a theory for the pathology of endometriosis (a condition where endometrial tissue grows outside the uterus). The coelomic epithelium develops into: peritoneum, pleura and the surface of the ovary. This combines retrograde and metaplasia and may explain the distant sites of endometriosis.
References
Abdomen
Epithelium
{{anatomy-stub