*Geek Box: Experimental Terminology
Spend any time reading research and you will come across terms that describe the environment in which an experiment was conducted. ‘In vitro’ comes from the Latin meaning, “within the glass”, and refers to experiments that are conducted outside of a living organism, for example in a cell culture petri-dish, or in a test tube. The issue with such studies is that the controlled environment does not necessarily replicate the biological environment occurring in the living organism.
‘In vivo’, meaning “within the living”, means the experiment is conducted in the whole living organism; a human, or a mouse, for example. The limitation of in vivo research is we may not gain insight into biological mechanisms, depending on the type of experiment or what exactly it is we want to know.
You may also see ‘ex vivo’, or “outside the living”: ex vivo studies are where experiments are conducted on a tissue taken from an organism, where the structural and biological properties of the tissue are maintained. The limitation here is that, although ex vivo may be considered to better replicate internal conditions than in vitro experiments, ex vivo studies still may differ in response from the whole-organism.
All lines of research have their place, particularly for biological sciences where we study complex organisms that are multi-cellular, and have various levels of cells, tissues, organs, and glands.