In the body of multi-cellular animals, some cells stay together and execute a definite function. These cells are either formed from the ectoderm, mesoderm or endoderm of the embryo and remain close together. Inter-cellular materials or matrix are there between these cells. These cells might be related or of dissimilar types. Arising from the embryonic cell layer when definite types of cells when stay in an exacting position of the animals’ body and jointly carry out a regular function, those cells and the inter-cellular materials or matrix secreted by them are cooperatively called the Tissue. That is to say, cells of an exacting tissue are related in its, source, function and organization. The subject in which the dissimilar types of tissue are discussed is called Histology.
So Animal Tissue is a assembly of specific cells and the intercellular essence around them that are adapted to work together in order to perform particular functions. There are four types of tissues found in animals: epithelial tissue, connective tissue, muscle tissue, and nervous tissue.