This document discusses four types of simple epithelium: squamous, cuboidal, columnar, and pseudostratified. Squamous epithelium is scale-like and found lining blood vessels and body cavities. Cuboidal epithelium lines small ducts and tubules, and can be secretory or absorptive. Columnar epithelium lines ducts of exocrine glands and the stomach, and is adapted for secretion and absorption. Pseudostratified epithelium appears to have multiple layers but actually has cells of different heights contacting the basement membrane, seen in airways.

1. SYED SHAHZAIB MUHAMMAD SPECIAL THANKS: ARS PMAS UAAR
14-arid-2069
Epithelium: Types of simple
epithelium
Squamous
Squamous means scale-like.
simple squamous epithelium is a single layer of flat scale-
shaped cells.
Both the endothelial lining of blood vessels and the mesothelial lining of the body cavities are
simple squamous epithelium.
Try to identify the simple squamous epithelia in these pictures.
Cuboidal
Lines small ducts, tubules.
It can have an excretory, secretory or absortive function - i.e. in
salivary glands.
This image opposite is of ducts in the kidney, which are lined by simple cuboidal epithelium.

2. Columnar
This picture shows columnar cells from the stomach. A few of the cells are outlined, to help you
identify them.
This is a single layer of cells, and the cells are all tall
columnar.
Tall columnar epithelium lines the ducts of many exocrine glands.
This type of epithelium is adapted for secretion and/or absorption, and can also be protective.
Simple secretory columnar epithelium lines the stomach and uterine cervix.The simple columnar
epithelium that lines the intestine also contains a few goblet cells.

3. In histological slides of pseudostratified epithelium, it looks as though some of the cells are not
in contact with the basal lamina, and the nuclei are at different levels. So it looks as though there
is more than one layer of cells.
However EM shows that all the cells contact the basal lamina, so this is a 'simple' epithelium.
But it is called pseudostratified, because of its appearance.
Pseudostratified ciliated columnar epithelium containing goblet cells lines most of the major
airways.
show labels
This is an example of pseudostratified epithelium, from
the jejunum.
Identify the goblet cells. What shape do the rest of the
epithelial cells have? (squamous, cuboidal or columnar?)
It is hard to identify the nuclei of the goblet cells.
However, the goblet cells have a very characteristic pale
purple staining due to the mucus that they contain.