• Are formed by all three germ layers..
• First tissue formed is epithelium tissue
• Cells are compactly packed with less or no intercellular matrix and have abundant cell junctions.
• High regeneration capacity.
• The cell there is no blood supply (asvascular)
• Have  Nerve supply…
• Function of epithelial cells are transcellular (diffusion membrane), absorption ,secretion and protection..

Cells are situated over a non -cellular gel-like layer called basement membrane..

• Basement Membrane has two parts basal lamina and reticular lamina…

1. Basal Lamina is the gel like sticky layer made up of glycoproteins and mucopolysaccharides..

• Secreted by cell product of epithelial cells themselves..

2. Reticular Lamina collagen fibre network secreted by underlining connective tissue provide strength..

Basement substance :-fuse off two basement membrane..

Types of epithelialal tissue

They are of two types simple and compound:-

1. Simple epithelium :-(pavement epithelial)

a. Simple squamous epithelium:-

• Flat like cells
• Central flat nuclear
• Polygonal cell with irregular boundaries
• Example :-inner wall of blood vessels and heart..
• alveoli, bowman's capsule ,serosa ,pulmonary cavity, abdominal cavity…

2. Simple Cuboidal epithelium:-

• Cube Like cells.
• Central round nucleus.
• Example:- ***DCT ( Distal convoluted tubule)

  I) Thyroid follicle , II) small pancreatic ducts

III) small salivary ducts…

It has two types:-

I) Brush boarded:- microvilli present on free surface of the cell…

•micovilli increases the surface area for absorption and secretion..

Example *****PCT ( proximal convoluted tubule)..

II) ciliated Cuboidal epithelium:-have cilia on its free surface..

Cilia is made up of microtubules….

--it has two types .

1. Kinocilium :-9 + 2 arrangement and unidirectional movement ( conveyor belt)
2. Sterocilium:-9+ 0 arrangement &no movement example hair cells…

3. simple columnar epithelium:-

• Tall and slender cells having basal nuclei.
• Example duct of pancreas ,lining of stomach.(gastric mucosa)..

•  Two types:-

1. Brush boarded:- small intestine..
2. Ciliated:- fallopian tube , trachea ,bronchi..

pseudosatisfied columnar epithelium:-

Falsely appeared to be multi layered ..

For example :-olfactory epithelium, inner ear….

b. Compound epithelium tissue:-

• These are multilayered
• Basal layer of cell i.e. columnar to cuboidal in shape
• Actively dividing and give rise to new cells to form new layers upside so called germinal layer..

Epithelium is a vascular so the cell grow upward in layer and supplier of Nutrition is decrease to upward the cells of upper layer become dead and called cornified cells and its function is to protect from (mechanical and chemical stress..)

 Compound Squamous epithelium has two types:-

1. Keratinized compound squamous epithelium:-

• As highly water resistance protein and non reactive
• As the cell go up in the layer keratin forms and field inside them
• Making cells or layer waterproof
• For example:- dry space of body (skin)

2. Non keratinized compound squamous epithelium:-

• Example mouth , pharynx ,larynx ,anal canal, vagina..

Transitional epithelium:-

• Act as thick as unstreched form and become thin at strechted form…
• The shape of cells at unstretched form is cuboidal ,polynomial, pear shaped cell..
• And become at square-shaped sell at stretched state..
• Example:- renal pelvis ,urinary bladder, ureter(urinary bladder) so called urothelium..