An Introduction to Human Anatomy and Physiology
Chapter Four: Cell Structure and Function
Introduction:
In 1665, the English scientist Robert Hooke observed thin slices of cork under a microscope and noted that the wood was made of tiny, box-like structures that he named “cells.” Subsequent observations by Hooke and other scientists showed that not just plants, but also fungi and animals were made up of cells. In fact,
all living creatures appeared to be made of cells.
Hooke’s drawing of “cells” in a piece of cork.
In 1839, German biologists Matthias Schleiden and Theodor Schwann formulated the
Cell Theory of Life, which has four claims. First, according to the cell theory, all living organisms consist of one or more cells. (Since a virus is not cellular, according to the cell theory, viruses are not alive.) Second, all cells arise through division of preexisting cells. Third, all vital functions of an organism occur within its cells. Finally, cells contain the hereditary information necessary both for regulating cellular function and for reproduction.
Introduction
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