Martini, Chapter 1, pp. 4-5, and Chapter 3, pp. These are important questions for understanding functional anatomy and physiology. The fundamental unit of the living body is the cell. Cells are self maintaining in that each cell is produced by the division of a previous cell.
Cells are the smallest units that perform all vital functions in a living organism.
Each cell maintains its own homeostasis. Homeostasis at the tissue, organ and organism level is a function of the combined activities of many different cells. The mammalian body contains two kinds of cells - somatic cells and germ cells. Germ cells are reproductive cells, that is, eggs or sperm. Somatic cells make up the rest of the body.