Library · Histology
Histology of the pleura
Make it clearer
If you take a small piece of pleura, the covering around the lung, and look at it under the microscope, you find two things stacked together. On top, facing the open space, is a layer of flat cells called mesothelium; underneath, holding it up, is connective tissue, the body's support material. That combination is called a serous membrane.
The way to picture it is as a bag: the mesothelium is the lining inside and the connective tissue is the fabric outside. And the cells of that lining, which are squamous, meaning flattened like scales, are not there just as a covering: they release serous fluid, a watery fluid that moistens the membrane. Rub two dry fingers together, then rub them again with a drop of water between them; the difference you feel is exactly what that fluid is for: cutting down the friction between organs.
In brief
The pleura is a serous membrane: it is a mesoderm-derived epithelium called mesothelium, resting on connective tissue.
These membranes are essentially sacs: the mesothelium lines the inside and the connective tissue sits on the outside.
The serous fluid secreted by the cells of this thin squamous mesothelium lubricates the membrane and reduces friction between organs.
Rub two dry fingers together, then rub them with a drop of water between them: that difference is what the fluid secreted by the mesothelium adds.
Sources (2)
- OpenStax, Rice UniversityAnatomy and Physiology 2e, 22.2 The LungsPublished
- OpenStax, Rice UniversityAnatomy and Physiology 2e, 4.1 Types of TissuesPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated