Mesothelium

Mesothelium
Cytology of normal mesothelial cells, with typical features.[1] Wright's stain
Histology of the peritoneal mesothelial lining, and underlying fibrous tissue. H&E stain.
Details
Precursor	Somatopleuric mesenchyme
Identifiers
Latin	mesothelium
TH	H2.00.02.0.02017, H3.04.08.0.00003
FMA	14074
Anatomical terminology [edit on Wikidata]

The mesothelium is a membrane composed of simple squamous epithelial cells of mesodermal origin,^[2] which forms the lining of several body cavities: the pleura (pleural cavity around the lungs), peritoneum (abdominopelvic cavity including the mesentery, omenta, falciform ligament and the perimetrium) and pericardium (around the heart).

Mesothelial tissue also surrounds the male testis (as the tunica vaginalis) and occasionally the spermatic cord (in a patent processus vaginalis). Mesothelium that covers the internal organs is called visceral mesothelium, while one that covers the surrounding body walls is called the parietal mesothelium. The mesothelium that secretes serous fluid as a main function is also known as a serosa.