. Epithelial Tissue Epithelial tissue is a sheet of cells that covers the body surface or lines the body cavity. It occurs in the body as a covering, as a lining epithelium and as glandular, epithelium . The functions of epithelium includes protection, absorption, filtration, excretion, secretion and sensory reception.
Based on the structural modification of the cells, the epithelial tissues are classified into simple epithelium and compound epithelium or stratified epithelium. Simple epithelium is composed of a single layer of cells. They are found in the organs of absorption, secretion and filtration. Simple epithelial tissue is further classified &RQQHFWLYH WLVVXH 6NHOHWDO PXVFOH (SLWKHOLDO WLVVXH 6PRRWK PXVFOH &DUGLDF PXVFOH 1HUYRXV WLVVXH Figure .
Types of Tissues in Human XI Std Biology-Zoology Chapter- %DVDO ODPLQD 8QGHUO\LQJ WLVVXH $SLFDOVXUIDFH RIHSLWKHOLXP &HOOQXFOHL $ 6LPSOHVTXDPRXVHSLWKHOLXP DLUVDFVRIWKHOXQJ % 6LPSOHFXERLGDO HSLWKHOLXP NLGQH\ & 6LPSOHFROXPQDU HSLWKHOLXP LQWHVWLQH ' 3VHXGRVWUDWLILHGFLOLDWHG FROXPQDUHSLWKHOLXP UHVSLUDWRU\WUDFW ( 6WUDWLILHGVTXDPRXV HSLWKHOLXP HVRSKDJXV Figure . Types of Epithelial tissues into squamous epithelium, cuboidal epithelium, columnar epithelium, ciliated epithelium and pseudostratified epithelium (Figure . ). The squamous epithelium is made of a single thin layer of flattened cells with irregular boundaries.
They are found in the kidney glomeruli, air sacs of lungs, lining of heart, blood vessels and lymphatic vessels and are involved in functions like forming a diffusion boundary and filtration in sites where protection is not important. The cuboidal epithelium is made of a single layer of cube like cells. This tissue is commonly found in the kidney tubules, ducts and secretory portions of small glands and surface of the ovary. Its main functions are secretion and absorption.
The columnar epithelium is composed of single layer of tall cells with round to oval nuclei at the base. It lines the digestive tract from the stomach to the rectum. The two modifications of this lining are the presence of microvilli on the apical surface of the absorptive cells and Goblet cell which secretes the protective lubricating mucus. The functions of this epithelium include absorption, secretion of mucus, enzymes and other substances.
If the columnar cells bear cilia on their free surfaces