Epithelial tissue lines body surfaces and cavities. It is classified based on cell shape (squamous, cuboidal, columnar) and number of cell layers (simple, stratified, pseudostratified). Simple squamous epithelium is a single layer of flattened cells found in the lungs, blood vessels, and heart. Stratified squamous epithelium has multiple layers of flattened cells and protects surfaces like skin and esophagus. Pseudostratified epithelium appears layered but is a single cell layer with irregularly placed nuclei, found in the respiratory tract.

1. EPITHELIAL TISSUE
BY
DAVID, BEAULAH M.

2. EPITHELIUM
EPITHELIUM is a tissue composed of cells that lines
the cavities and surfaces of structures throughout the
body
Epithelial tissue is avascular (no blood vessel )
Epithelial tissue receives nutrition by diffusion from
underlying C.T

4. CLASSIFICATION OF EPITHELIAL TISSUES
can be classified based on:
1. Their basic shape
2. the number of layers (in which the
cells are arranged).

5. BASED ON SHAPE
Cells can be
Squamous
Cuboidal
Columnar
Squamous: have an appearance of flat plates
The cells, tend to be horizontally flattened, shaped like an egg
Cuboidal: these are cuboid in shape, the cells have spherical
nucleus at the centre
Columnar : these are elongated and column shaped
they are taller as they are wider

6. BASED ON NUMBER OF CELL LAYERS:
 Simple
 Stratified
 Pseudostratified
Simple epithelium
Epithelium with only one layer
Stratified epithelium: has two or more cell layers
Pseudostratified epithelium: they are not truly
stratified; they look as if they have different cell
layers but it is only one layer.

7. The epithelium can also be named using
a combination of the two bases
Example
 Simple squamous
 Stratified squamous
 Simple cuboidal
 Simple columnar

8. SIMPLE SQUAMOUS
EPITHELIUM:
– Single layer of flattened
cells
– Function: secretion,
absorption, and filtration
– Location: lines the
lungs, blood vessels and
heart

10. – Many layers of flattened
cells
– Function: protection
– Location: it is found
where body linings have
to withstand mechanical
or chemical assault e.g
outer layer of skin,
vagina, esophagus
STRATIFIED SQUAMOUS EPITHELIUM

11. ► Cells appear to be layered
due to irregularly placed
nuclei but each cell touches
the basement membrane
► May contain cilia – aids in
movement of particles
► Function: protection,
secretion, movement of
mucus and sex cells
► Location: respiratory tract,
reproductive tract
PSEUDOSTRATIFIED EPITHELIUM

12. ►Tissue that changes in
response to tension
►Found in organs that
need to stretch
►Location: urinary
bladder, ureters, urethra
TRANSITIONAL EPITHELIUM

13. TYPES OF EPITHELIUM AND THEIR LOCATION
EPI LOCATION FUNCTION
SIMPLE SQUAMOUS Air sacs of lungs, blood
vessels
Diffusion and filtration
SIMPLE CUBIODAL EPI Kidney, ovary, duodenum Secretes and absorbs
Simple columnar Digestive tract, gall
bladder, jejunum,
stomach, ileum
Absorbs, secretes
Stratified squamous Esophagus, tongue,
vagina, skin
Protect against abrasion
Transitional epithelium Urinary bladder, ureter
Stratified cuboidal Sweat glands, salivary
glands, mammary glands
secretes
Pseudostratified
epithelium
Trachea, larynx Secretes mucus , has cilia

14. LUNGS SIMPLE SQAMOUS

15. LARYNX PSUEDOSTRATIFIED

16. TRACHEA PSEUDOSTRATIFIED

17. SALIVARY GLAND STRATIFIED CUBOIDAL

18. ESOPHAGUS STRATIFIED SQUAMOUS

19. JEJENUM SIMPLE COLUMNAR

20. GALL BLADDER SIMPLE COLUMNAR

21. VAGINA STRATIFIED SQUAMOUS NON
KERATINIZED

22. OVARY SIMPLE CUBOIDAL

23. STOMACH SIMPLE COLUMNAR

24. MAMMARY GLAND STRATIFIED CUBOIDAL

25. ILEUM SIMPLE COLUMNAR

26. DUODENUM SIMPLE CUBOIDAL