Histology and Its Methods of Study

Introduction
All living things (or organisms) are built from cells: small, membrane enclosed units filled with a concentrated aqueous solution of chemicals, and equipped with the extraordinary ability to create copies of themselves by growing and then dividing into two cells. Higher organisms, including ourselves, are communities of cells derived by growth and division from a single founder cell. Every animal or plant is a large colony of individual cells, each of which performs a specialized function that is regulated by complicated systems of cell-to-cell communication. Cells, therefore, are the fundamental units of life. Cell biology: is the study of cells and their structure, function, and behavior.
Unity and Diversity of Cells: cells are not all alike; in fact, they can be wildly different. Here we can summarize some of the cells characteristics:
1- Cells Vary in Appearance and Function.
2- Living Cells All Have a Similar Basic Chemistry.
3- Genes Provide the Instructions for Cell Form, Function, and Complex Behavior