Schwann cell

Schwann \ˈshvän\ , Theodor Ambrose Hubert (1810–1882), German anatomist and physiologist. Schwann is regarded as the founder of modern histology. He is best known for his conception of the structure and function of cells: he defined the cell as the basic unit of human anatomy. Investigating the digestive processes in 1836, he isolated a substance responsible for digestion in the stomach. He named this first enzyme prepared from animal tissue pepsin. Schwann is also regarded as a founder of the germ theory of putrefaction and fermentation. He was the first to investigate the laws of muscular contraction by physical and mathematical methods and to demonstrate that the tension of a contracting muscle varies with its length. In 1838 he published his description of the myelin sheath covering peripheral axons. He also formulated a basic principle of embryology by observing that the egg is a single cell that eventually develops into a complete organism.