Question

What exactly are exogenous substances?

Answer 1

Exogenous substances:

• In medical imaging, for instance, an exogenous contrast agent is a liquid injected intravenously into the patient that improves the visibility of a pathology, such as a tumour.
• In contrast to endogenous factors, exogenous factors are those substances that are present and active in a single organism or live cell but were generated externally to that organism.
• Exogenous compounds come from sources outside of living things, whereas endogenous substances are those that come from within a living thing.

Examples:

• Cells, tissues, and organs are examples of endogenous substances, whereas pharmaceuticals and medicines are instances of exogenous substances.