© 1999 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999

1.2.1.10 Cells and Tissues

The doctrine of the essential cellular nature of living things was established by 1840. Modern cell theory³²²³ began in botany. The Jena botanist Matthias Schleiden (1804-1881) observed that plants were aggregates of cells, existing as self-reproducing living units. Exploring analogies between animals and plants in structure and growth, Theodor Schwann (1810-1882) took up the idea, maintaining that all these phenomena could also be demonstrated in animal structures. Thus living cells were basic to living things, and cells incorporated a nucleus and an outer membrane.

Jacob Henle (1809-85) applied cell biology to man. His three-volume Handbuch der systematischem Anatomie des Menschen (Handbook of Systematic Human Anatomy) (1866-1871) addressed the body from an architectural standpoint, describing its macro- and microscopic structure. Henle discovered kidney tubules and was the first to describe the muscular coat of the arteries, the minute anatomy of the eye and various skin structures, earning him a reputation as the Vesalius of histology (the study of tissues). Physiologists stressed organ and tissue function -- Claude Bernard (1813-1878) emphasized the experimental method in establishing biological knowledge and urged that medical practice should be grounded in such knowledge.

Histology was raised to the status of an independent science by the Swiss microanatomist Albert von Kolliker (1817-1905), who wrote the first textbook on the subject, Handbuch der Gewebelehre des Menschen (Handbook of the Tissues of Man) (1852). The medical implications of cell theory were taken up by Rudolph Virchow (1821-1902), who dominated German biomedical research for half a century. Virchow extended the cell concept to diseased tissues; his Die Cellularpathologie (Cellular Pathology) (1858) analyzed such tissues from the point of view of cell formation and cell structure. Virchow initiated the idea that the body may be regarded as a "cell state in which every cell is a citizen." Disease is often but civil war, and white cells are likened to scavengers or police. Virchow maintained that cells always arose from pre-existing cells through cellular division. Since Kolliker and Virchow, the study of the intimate structure and workings of the cells themselves, as distinct from the tissues, has become a separate science, cytology, further extended to the study of cells in disease, or cytopathology (Chapter 21).

Last updated on 5 February 2003