Here are the types of epithelium identified in the sections: 1. Simple columnar epithelium 2. Simple cuboidal epithelium 3. Pseudostratified ciliated epithelium 4. Simple columnar epithelium 5. Simple ciliated columnar epithelium 6. Simple cuboidal epithelium 7. Pseudostratified ciliated epithelium 8. Simple columnar epithelium 9. Pseudostratified ciliated epithelium 10. Mesothelium 11. Pseudostratified ciliated epithelium

1. Epithelial tissues I.

2. 1. Simple squamous epithelium
2. Simple cuboidal epithelium
3. Simple columnar epithelium
4. Pseudostratified columnar
epithelium with cilia

3. Characteristics of the epithelial cells:
They are tightly packed together with very little intercellular
matrix. (Intercellular junctions: t ight j unct ions, zonulae
adherent es, desm osom es, gap j unct ions).
Epithelia are derived from all t hree em bryonic germ layers.
The principal functions of epithelial tissues are covering and
lining of surfaces (cove r in g e pit h e lia ), absorpt ion of
subtances (a bsor pt ive e pit h e liu m ), secret ion of
substances (gla n du la r e pit h e liu m ), sensation (sensory
epithelium/neuroepithelium).
The epithelial cells rest on a basem ent m em brane (lamina
lucida + lamina densa + lamina fibroreticularis), and are
connected to this membrane by hemi- desmosomes.
The apical surface of the epithelial cells may be equipped
with structures that greatly increase t he surface area
(microvilli, stereocilia), and structures which are
responsible for motility (kinocilia, flagellum).

4. The simple squamous epithelium consists of a single row of
flattened cells. In cross section the cytoplasm of these cells
is extremely attenuated, so that it is hardly visible. The part
of the cell containing the nucleus is enlarged, the nucleus
stands out in relief.
Location: squamous alveolar cells in the lung (type I
pneumocytes), parietal wall of the renal Bowman capsule,
the narrow segment of renal loop of Henle.
Special types of simple squamous epithelium:
1. Endothelium: epithelium lining the inner surface of the
heart and blood vessels
2. Mesothelium: epithelium of serous membranes lining
certain body cavities (pericardium, pleura, peritoneum)

5. Simple squamous epithelium
1.Mesenterium (Ag)
Actually it is not a section,
but a very thinly stretched
membrane (mesenterium
of frog or rat), and each
side of this membrane
presents mesothel cells
arranged mosaically, side
by side.
Mesothel
cells
The cell-boundaries are
visible by silver nitrate
treatment as silver
granules deposit in the
intercellular spaces.

6. It is formed by one row of cuboidal cells that possess
spherical nuclei .
Location:
Follicles of the thyroid gland
Distal and proximal renal tubules
Epithelium germinativum covering the ovary
Amniotic epithelium
The cuboidal cells may have resorbing function,
presenting m icr o villi attached to their apical surface
(e.g. proximal renal tubules).

7. Simple cuboidal epithelium:
68. Thyroid gland (HE)
The simple cuboidal
epithelium of the follicles
represent an epithelium of
both covering and
endocrine glandular type
involved in the secretion of
thyroxin. The cells are
flattened in hypofunction
of the gland, and they are
Cell nuclei Follicles taller in hyperfunction.
The cell boundaries are
hardly visible, and the
cuboidal epithelium might
be recognized according to
the spherical shape of the
nuclei.

8. Simple columnar epithelium:
It consists of a single row of cells that have cylindrical or
prismatic shape and oval nuclei.
Location:
In the digestive tract from the cardia to the anal canal.
Striated ducts of the salivary glands
Epithelium of the uterus
Cells that have resorbing function present brush border
formed by microvilli that are disposed on the apical surface.
Location of the simple columnar epithelium with brush
border:
Small and large intestine
Location of the simple ciliated columnar epithelium:
Oviduct

9. Simple columnar epithelium:
49. Gallbladder (HE)
Oval cell nuclei The inner surface of the
gallbladder is lined by
simple columnar
epithelium equipped with
brush border.
The cell boundaries are not
clearly visible, but this
form of epithelium may be
recognized by the oval
nuclei disposed in one row.
The brush border exhibits
positive PAS reaction.

10. The cells form a single row, but their nuclei are disposed at
different levels so that it gives the illusion of stratification.
Every cell is lying on the basal membrane, that s why this is
a type of simple epithelium. Cells that reach the surface
usually present cilia.
Location of the pseudostratified epithelium with stereocilia:
Ductus epididymidis
Ductus deferens
Location of the pseudostratified epithelium with kinocilia:
Respiratory tract to bronchioles
Auditory tube, lining of the tympanic cavity
Inner surface of the lacrimal sac

11. The inner surface of the
The trachea is covered by
epithelial pseudostratified
lining of
epithelium with kinocilia.
the trachea
Goblet cells appear
among the ciliated
columnar cells; their
secretion product is not
stainable with H.E., but
exhibits positive PAS
reaction.
Unstained
goblet cells

12. I de n t ify t h e t ype of t h e e pit h e liu m
in t h e follow in g se ct ion s!

25. 1. Simple columnar epithelium (gallbladder)
2. Simple cuboidal epithelium (medulla of kidney)
3. Pseudostratified ciliated epithelium (respiratory tract)
4. Simple columnar epithelium (small intestine)
5. Simple ciliated columnar epithelium (oviduct)
6. Simple cuboidal epithelium (medulla of kidney)
7. Pseudostratified ciliated epithelium (respiratory tract)
8. Simple columnar epithelium (uterus)
9. Pseudostratified ciliated epithelium (tail of the
epididymis)
10. Mesothelium
11. Pseudostratified ciliated epithelium (tail of the
epididymis)