There are four main types of tissues in the human body: epithelial, connective, muscle, and nervous. Epithelial tissue forms sheets that cover surfaces and line cavities. There are several categories of epithelial tissue including simple squamous, simple cuboidal, simple columnar, pseudostratified columnar, stratified squamous, stratified cuboidal, and transitional epithelium. Each type is named based on the number of cell layers and shape of cells, and they perform functions like protection, secretion, absorption, and sensory reception in different parts of the body.

2. Tissue
• Groups of cells that are similar in structure
and perform a common or related functions
are called TISSUE

3. Tissues
• The tissues of the human body include four
major types: general function
• Epithelial: covering
• Connective: support
• Muscle: movement
• Nervous: control

4. Types of Tissue!!

5. EPITHELIAL TISSUES

6. EPITHELIAL TISSUES
• Epithelial Tissue: is a
sheet of cells that
covers a body surface
or lines a body cavity
• Nearly all substances
received or given off
by the body must pass
through an epithelium
layer.

7. EPITHELIAL TISSUES
• Epithelial Tissue lacks of
blood vessels, contains
little intercellular
material and are
continually being
replaced
• They function in
protection, secretion,
absorption, filtration,
excretion, and sensory
reception.

8. EPITHELIAL TISSUES
• Epithelium Tissue has
many characteristics
that separate it from
other tissue types
• ET has an apical surface
(near the top) and a
basal surface (near the
bottom)
• Supported by
connective tissue.

9. EPITHELIAL TISSUES
• Each Epithelium Tissue is given two names.
• The first name indicates the number of cell
layers present.
– Simple- one layer
– Stratified- more than one layer
• The second describes the shape of its cells
– Squamous, cuboidal, and columnar.

10. EPITHELIAL TISSUES
• .

11. Simple Squamous Epithelium
• This tissue consists of a single layer of thin, flattened
cells through which substances can pass easily. So
delicate they can easily be damaged.
• Common site of diffusion and osmosis. Its functions
in the exchange of gases in the lungs
• Lines the air sacs of the lungs (gas exchange), forms
the walls of the capillaries, lines the insides of blood
vessels and lymph vessels.
• Covers the membrane that line body cavities.

12. Simple Squamous Epithelium

13. Simple Squamous Epithelium

14. Simple Cuboidal Epithelium
• This tissue consists of a single layer of cube-
shaped cells. Usually have a centrally located
spherical nuclei
• It carries on secretion and absorption.
Secretes glandular products.
• Covers the ovaries, lines the kidneys, tubules
and ducts of certain glands like pancreas and
the liver.

15. Simple Cuboidal Epithelium

16. Simple Cuboidal Epithelium

17. Simple Columnar Epithelium
• The tissue is composed of a single layer of elongated
cells whose nuclei are usually at about the same
level, near the basement membrane.
• Some have cilia some do not
• Secretes and absorbs…this tissue is thick!!
• This tissue lines uterus and portions of the digestive
tract like small/large intestines and stomach.

18. Simple Columnar Epithelium

19. Simple Columnar Epithelium

20. Simple Columnar Epithelium

21. Pseudostratified Columnar Epithelium
• They appear stratified but are NOT, They appear to
have two or more nuclei but they each reach the
basement level.
• Goblet cells scattered throughout the tissue that
secret mucus, which the cilia sweep away.
• It lines tubes of the respiratory system. The mucus
and cilia created by this tissue trap the dust and
microorganisms that enter the airway.

22. Pseudostratified Columnar
Epithelium
• “C” the nuclei appear
at various levels giving
it the stratified
appearance
• “B” the cilia can easily
be seen

23. Pseudostratified Columnar Epithelium

24. Pseudostratified Columnar
Epithelium

25. Stratified Squamous Epithelium
• Named for the shape of the cells,…consists of many
layers, relatively thick. Cells nearer the surface are
flat where as the deeper are cuboidal and columnar.
• Tissue can contain Keratin, which is a protein that
accumulates and protect the underlying tissue.
• Epidermis-outer most layer of the skin
• Also lines the skin and lines the oral cavity, throat,
vagina, and anal canal.

26. Stratified Squamous Epithelium
• Observe that the
surface cells (at B) are
flattened (are
squamous).

27. Stratified Squamous Epithelium

28. Stratified Cuboidal Epithelium
• This tissue is composed of two or thee layers
of cube-shaped cells.
• It lines the larger ducts of the mammary
glands sweat glands, salivary glands, and
pancreas. Forms the lining of ovarian follicles
and seminiferous tubules
• It functions in protection.

29. Transitional Epithelium
• This tissue is specialized to change in response
to tension..
• Transition epithelium is unstretched and
consists of many layers when the organs wall
contract the tissue stretches and appears
thinner when the organ is distended.
• Forms the lining of the urinary bladder and
lines the ureters and part of the urethra.

30. Transitional Epithelium

31. Transitional Epithelium