Cytoplasm- Definition, Structure, Functions and Diagram


The cytoplasm is the semi-fluid substance that fills the entire space of a cell from the outer layer of the double membrane-bound nucleus to the inner layer of the cell membrane. It is composed of water, salts, and various organic molecules. Some intracellular structures, such as the nucleus and mitochondria, are enclosed by membranes that separate them from the cytoplasm. The cytoplasm is sometimes described as the non-nuclear content of protoplasm, which is the living material of the cell.

The cytoplasm was discovered in the year 1835 by Robert Brown and other scientists . Brown was the first to observe the nucleus in plant cells and coined the term "cell nucleus". He also noticed a granular substance surrounding the nucleus, which he called "areolar tissue" or "cell substance". Later, other scientists such as Felix Dujardin, Matthias Schleiden, Theodor Schwann, and Rudolf Virchow studied this substance and gave it different names, such as "sarcode", "cytoblastema", "protoplasm", and "cytoplasm" .

The term "cytoplasm" was first used by Carl Nägeli and C. Cramer in 1855 to refer to the fluid inside the cell membrane. However, it was not until 1896 that Albrecht von Kölliker defined cytoplasm as the part of protoplasm that excludes the nucleus. Since then, cytoplasm has been recognized as a complex and dynamic system that contains various components and performs various functions in the cell.