Simple Squamous Epithelium
Simple squamous epithelium, oviduct.
is a term for the epithelial layer of the
serous membranes (
that line the body cavities and cover the organs that
project into the cavities. The other component of these
membranes is the loose connective tissue layer beneath
the mesothelium. The membrane that lines the cavity
wall constitutes the
, and the
) covers the organs located within the cavity.
The mesothelium secretes a slippery
that allows organs to easily slide against and over
each other or against the cavity wall (e.g., beating heart,
expanding or contracting lungs, peristaltic activity of the
intestine) without damage to the mesothelium.
A representation of a simple squamous
epithelium lining a body cavity.
are ﬂ attened, generally pentagonal in
shape, and form irregular borders with one another. The
is immediately adjacent to the meso-
thelium, which is barely visible with the light microscope.
The basement membrane includes the
additional layer, the
. The term “basal lam-
ina” is used at the electron microscope level and includes
found beneath the basement membrane. The loose con-
nective tissue beneath the basement membranes of meso-
thelia is the second component of the serous membranes
(cancer of the mesothelium) is a
neoplasm that arises from surfaces of the
cavities. It is only occasionally found in the
mesothelium. This type of tumor is more
commonly seen in individuals who either were exposed
to asbestos or who smoke. Mesothelioma cells develop
long, slender, and curved microvilli. These tumors may
invade nearby tissues and organs. In general, cancer
cells are those that can
(spread) from their
original site to distant parts of the body, and mesothe-
liomas are no exception. The lymphatic system is a
common route through which metastasis may occur.
Normal mesothelial cell
Excessive ﬂ uid in a mesothelial-lined cavity is called an
“effusion,” for example, a
. Inﬂ amma-
tion of the pleura is called
; of the peritoneum, it
; and of the pericardium,
These may exist in conjunction with a variety of clinical
conditions or diseases.