Histology is the study of the tissues of the body and how these tissues are arranged to constitute organs. Stop and Think: In order to study tissues, how would you divide the vast field of histology into two interacting components? What kinds of organ systems might be present in all tissues? Solution The vast field of histology can be divided into two interacting components which are cells and the extra cellular matrix. Cells are the structural and functional unit of life. Some substances secreted by cells form the extra cellular matrix that serve to provide structural and biochemical support to these cells. All tissues types (epithelial, connective, muscular and nervous tissues) have blood..