Health & the Body - 48 free documentaries about the human body.
Start with How a Woman's Donated Body Became a Digital Cadaver (19 min, National Geographic), then Testosterone — new discoveries about the male hormone (42 min, DW Documentary). All 48 documentaries here are free to watch from their makers' official uploads. To read deeper, the top-rated book on the human body is The Body by Bill Bryson.