Fluorescence occurs when a molecule absorbs light at a specific wavelength and then emits light at a longer wavelength. In histology, sections of tissue are treated with fluorescent labels that bind selectively to target molecules. These labels can be naturally fluorescent proteins like GFP or synthetic dyes. When exposed to light of the excitation wavelength, these labels emit light that can be captured by a microscope, revealing the location and abundance of the target molecules.
