Colorized scanning electron microscope composition of human sperm traveling through a fallopian tube.

Image courtesy of Steve Gschmeissner/Getty.

Carcinoma cells via fluorescence microscopy.

Image courtesy of Frederick Keeney, The Wistar Institute, Philadelphia.

Mouse brain vasculature, as imaged by light sheet fluorescence microscopy.

Image courtesy of Ali Erturk, Munich, Germany.

Stereomicrography of bacterial growth in a petri dish.

Image courtesy of Neil James Egan, PPG Industries, Cleveland, Ohio.

A human donor central retinal artery was cannulated (intubated) and perfused with Lectin FITC, a specific protein chemically linked to a fluorescent dye. The microvasculature of the optic nerve head area at the center is visible.

Image courtesy of Dong An, Lions Eye Institute, Australia.

Using confocal, deconvolution and image stacking techniques, a micrograph of a human I pluripotent stem cell-derived cardiac organoid.

Image courtesy of Syed Ashraf, Divya Sridharan and Salvia Zafar, Ohio State University.

A confocal micrograph of human neurons reprogrammed from skin cells.

Image courtesy of  Bruno Cisterna and Eric Vitriol, Medical College of Georgia at Augusta University.

A confocal micrograph of fluorescently marked mouse colon.

Image courtesy of Marius Mählen, Koen Oost, Prisca Liberali and Laurent Gelman, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.

The intricate architecture of the endoplasmic reticulum, the largest organelle in most cells, is depicted in this mouse brain cancer cell. The actin cytoskeleton in cyan and the endoplasmic reticulum in red.

Image courtesy of Halli Lindamood and Eric Vitriol, Augusta University.

A cell’s cytoskeleton provides structural support, maintains cell shape and is involved in processes like cell movement and intracellular transport of substances. Actin and tubulin are primary components of two main types of cytoskeleton protein. In this micrograph of rat liver cells, actin is shown in orange and tubulin in white.

Image courtesy of Francisco Lázaro-Diéguez, Albert Einstein College of Medicine.