- Epithelial tissue covers the whole surface of the body.
- Epithelial tissues are made up of cells that are closely packed and are composed of one or more layers.
- This tissue is specialised to form the covering of all internal and external body surfaces.
- Epithelial tissue that occurs on surfaces on the interior of the body is known as endothelium.
- It acts as a barrier to keep different body parts separate.
- Anything that enters the body has to cross any one of the above mentioned epithelial tissues.
SQUAMOUS EPITHELIAL TISSUE
- Cells are flat and thin.
- Consist of single layer of flat cells in contact with the basal lamina.
- The skin that protects our body is made up of squamous epithelium. As they are arranged in many layers they are called as stratified squamous epithelium.
- They are found where rapid diffusion is required.
- They are found in Capillaries (blood capillaries), glomerulus (part of excretory system).
- Present in: esophagus, lining of buccal cavity.
CUBOIDAL EPITHELIAL TISSUE
- These are cube shaped cells.
- Nucleus is located at the centre.
- The cells of cuboidal epithelium perform the function of secretion and absorption.
- This epithelial tissue fold inward and form a Multicellular gland called GLANDULAR EPITHELIUM.
- Found in: lining of kidney tubules, surface of ovaries, linings of nephrons, duct of salivary glands.
COLUMNAR EPITHELIAL TISSUE
- They are pillar like or rod shaped.
- When these tissues bear cilia on them they are known as CILIATED COLUMNAR EPITHELIAL tissues.
- Cilia are hair like outgrowth of small size which helps in passage of the substance from one part to other.
- Present in: inner lining of intestine, stomach, parts of respiratory and reproductive as well as digestive system.