Pseudostratified columnar
epithelium
• It consists of columnar cells crowded very
closely together.
• In cross section, the nucIei appear to be on two
or more levels and because of the crowding, the
cells appear distorted, and they all do not reach
the surface.
• But in fact every cell rests on the basement
membrane, so the epithelium is technically
"simple", in spite of appearances.
Cells that reach the surface are either
ciliated or goblet cells
• The goblet cells secrete mucous, which forms a film on
the luminal surface of the respiratory passages and
prevents duct from being inhaled into the lungs.
• The cillia move the mucous containing the dust particles
up and out of the respiratory passages.
• The cells that do not reach the surface probably,serves
as progenitor cells producing new cells.
1- Non ciliated pseudostratified epithelium
Vas deferens, human - H&E
2- Ciliated pseudostratified epithelium lines
the mucosa of the trachea. Most of the tall
(columnar) cells are ciliated, a specialization that allows
dust and mucous to be swept upward and eliminated
Psuedostratifed epithelium is
classified into:
1- Non ciliated pseudostratified epithelium
Vas deferens, large ducts, male urethra
2- Ciliated pseudostratified epithelium
• the respiratory tract, e.g. trachea, and
• Epididymis (in the male reproductive
system).
Ciliated pseudostratified
epithelium, Epididymis
Stratified epithelium:
1.Stratified Squamous Epithelium
2.Stratified cuboidal Epithelium
3.Stratified columnar Epithelium
4.Transitional Epithelium
1. Squamous stratified epithelium
• consists of flattened (squamous) cells on the surface overlying
multiple layers of cells that usually are more cuboidal toward the
base of the epithelium.
• The innermost layer (stratum germinativum):
*Contains basophilic, polyhedral cells.
*metabolically active and show mitotic figures to replace those lost
from the outer surface.
may contain tonofibrils (the precursors of keratin).
• Outer layer may be (types of squamous stratified)
• keratinized (dead and hardened) on dry surfaces such as skin, .
OR
• nonkeratinized on wet, mucous surfaces, are seen in the body
opinings such as:
• Mouth, Tongue
• Esophagus,
• Vagina
Stratified squamous epithelium,
keratinized
Skin, epidermis
stratified squamous, keratinized
epithelium, plantar skin (H&E)
Artificial spaces
Artificial spaces
Basal layer
Individual cells of stratified squamous
epithelium
Location of the basement
membrane
Stratified squamous epithelium, non
keratinized, tongue, vertical section
Stratified squamous epithelium, non
keratinized Esophagus, mucosa (cross
section)
stratified squamous,
non/keratinized epithelium,
vagina (H&E)
Lumen of vagina
Outside lumenal side of epithelium
Stratified squamous nonkeratinized
epithelium
Basal side of epithelium
stratified squamous,
non/keratinized epithelium, vagina
(H&E)
Cuboidal stratified epithelium
• Contains tow or more layers of cuboidal cells.
• The basement membrane is usually present
• The free surfaces have a distinct borders.
• It is uncommon type
• Is found in the ducts of the sweet glands and in the
lining of vesicular ovarian follicles (Graffian follicles)
Cuboidal stratified epithelium, Two
Layers
This is sweat gland variant with two layers of
cuboidal cells.
Cuboidal Stratified epithelium lining
of developing ovarian follicles.
T. s. in
mammalian
ovary
showing,
primary and
secondary
follicles
A magnified previous Cuboidal
stratified epithelium
Membrana granulosa
Basement membrane
Cuboidal Stratified epithelium
Testis, young and mature - H&E
Columnar stratified epithelium
• Basal layer is cuboidal or spherical cells
• Columnar layer is above
• Is found on the wet surfaces , where more
protection is required
• Is uncommon,
• but examples:
**Ciliated (nasal surface soft palate)
**Non ciliated (male urethra penis).
Transitional epithelium,
•
•
•
•
Basal layer is columnar cells
followed by polygonal cells going toward the surface
Then followed by pyriform cells
And eventually by pear-shaped dome cells that are convex on
their free border. These cells contain numerous mitotic figures,
large amount of DNA, polypoid nuclei and may be binucleated.
• The basement membrane is not visible in light microscopy.
• The name "transitional" derives from this tissue's ability to
change its shape squamous when stretched.
• also called urothelium, is a stratified epithelium lining the
distensible walls of the urinary tract.
• Function: distention
• Examples: urinary bladder, ureter
The transitional epithelium is highly magnified:
Note that the cells at the exposed surface (A) are large and
rounded. They are also larger than the cells at the attached
surface (B).
Compare this
tissue to
Stratified
Squamous which
has squamous
cells at its
exposed
surface.)
The ureter is lined by transitional epithelium
adventitia
lumen
Mucosa / submucosa
muscularis
ureter (Lee's stain)
Lumen of ureter
Surface cells
Provided slides
1.
2.
3.
Non ciliated pseudostratified epithelium Vas deferens, t.s.
Ciliated pseudostratified epithelium trachea, t.s
Ciliated pseudostratified epithelium Epididymis t.s
4.
Stratified squamous epithelium, keratinized epidermis skin, v.s.
5.
6.
Stratified squamous epithelium, non keratinized, tongue, vertical section
Stratified squamous epithelium, non keratinized Esophagus, mucosa (cross
section)
stratified squamous, non/keratinized epithelium, vagina t.s.
Cuboidal stratified epithelium, Two Layers, sweat gland, skin, v.s.
7.
8.
9.
Cuboidal Stratified epithelium lining of developing ovarian follicles.
Mammalian ovary, t.s.
10. Cuboidal Stratified epithelium, seminiferous tubules, Testis, young
and mature – t.s.
11.
12.
The transitional epithelium. Urinary bladder, t.s.
The transitional epithelium, ureter, t.s