Alfonso Rodríguez-Baeza and Marisa Ortega-Sánchez (2009). Photomicrograph of the microscopic blood vessels that shuttle oxygen and nutrients to neurons in the brain, obtained with a scanning electron microscope. This sample, from Human cerebral cortex, shows a large blood vessel at the surface of the brain (top), which sends down thin, densely branched capillaries to deliver blood throughout the entire cortex.