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Epithelium-1.ppt
1.
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
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.
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.
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.
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.
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.
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.
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.
