Organ Man, with Arteries, the Stomach and Internal Organs, artist unknown, from The Apocalypse, c. 1420–1430

Nude Female Anatomical Figure, artist unknown, from Arzneibuch, 1524–c. 1550

From The Art of Medicine: Over 2,000 Years of Images and Imagination, culled from the Wellcome Collection of London, via Brain Pickings.