Cytology

The cell is the basic building block of all living things. Cytology is the study of cells. Hooke in 1665 was the first person to use the term cell in relation to the compartments he saw when examining cork under a light microscope.

Scleiden and Schwann in the early nineteenth century devised cell theory:

• all cells have an underlying structural similarity
• the cell is a dynamic functional unit
• cells are the basic units of all living tissues and in turn, all living organisms
• hence, the organism is the sum of all its cells and their interactions

Human cells are eukaryotic, with membrane-bound organelles and more complex internal structure than equivalent prokaryotic cells e.g. bacteria.