Rudolf von Kölliker introduced the term cytoplasm in 1863. He originally used it as a synonym for protoplasm before the definition shifted over decades to mean cell substance and organelles outside the nucleus.
At length scales smaller than 100 nanometers, the material acts like a liquid while larger scales show gel-like behavior instead. Some theories propose the cytoplasm functions as a glass-forming liquid approaching the glass transition depending on component concentrations.
Cytosol makes up about 70% of the cell volume and contains a complex mixture of filaments and water. Actin filaments and microtubules form the cytoskeleton network inside this matrix along with soluble proteins and small structures like ribosomes.
Many metabolic pathways occur within the cytoplasm including glycolysis and photosynthesis. Processes such as cell division also take place here alongside signaling activities involving calcium ions.
Félix Dujardin refuted the naturalist position in 1834 by challenging models linking microscopic cellular structures to macroscopic internal mechanisms. He argued against the idea that intra-cellular artifacts formed derivative pathways linking microscopic structures to macroscopic mechanisms.