The human body is one of the most intricately-functioning creations we know about. The cells, tissues, and organs of our body all serve their job, all working towards the common cause of sustaining your life. There are over 200 different types of cells, and 79 types of organs, all with their own unique set of tasks in this mission. So, logically, when depicting these in fiction, what is the best way to portray them individually?
This trope is when the inside of the body meets Cast of Personifications. Welcome, to The Human Body!
Walk along the blood vessel streets, on your way from the Stomach Facility to the Office of the Heart. While there, take a look at those hard-working Cardiomyocyte managers, doing their tasks of sending Red Blood Cells (and their deliveries) around the body. Oh no, is that a virus attacking?! Thank God those White Blood Cell police officers are here to fight them off!
This trope is not to be confused with "Fantastic Voyage" Plot, although the two are not mutually exclusive. While a "Fantastic Voyage" Plot involves any case of ordinary people travelling into and around a body, it only crosses over into this trope when they go from dealing with faceless giant white blobs to dealing with border patrol officers in the Membrane.
The degree of individuality in personification can vary — sometimes it's sentient cells, sometimes it's sentient organs, sometimes it's entire sentient systems — but the idea is the same.
Anytime you see Organ Autonomy, you can always expect it to either be paired with this or Animate Body Parts, depending on if the individually-sentient organs and cells are depicted as humanoids or... you know, actual organs and cells. If an ordinary person shrinks down, enters the body, and can interact with these personifications, it crosses over with "Fantastic Voyage" Plot. If the personification is restricted to the thoughts of the brain and emotions, then that is Ghost in the Machine. Sperm as People is a subtrope.
- Cells at Work! entirely revolves around a large city, representing a body, filled with workers, all representing different cells. The main characters are a clumsy Red Blood Cell, one of the many responsible for delivering nutrients and oxygen around the body as couriers, and a White Blood Cell, who works alongside a team of ruthless assassins that target and (quite violently) kill pathogens infecting the body. We also get to see many other recurring cells, including the child-like Platelets who do reconstructions after attacks, heavy-duty-weapons-wielding Macrophages, and the Helper T Cell, who strategizes for a team of Killer T Cells. We also see horrifically accurate depictions of things like viruses and a Cancer Cell, who act as some of the more threatening antagonists.
- Cells at Work! CODE BLACK is an Ascended Fridge Horror spin-off of Cells at Work! that deals with the implications of how this would appear for an unhealthy body — years of drinking, smoking, and unsafe sex has left this body a dangerous, grimy, violent wreck. The kidney is filled with overworked slave-girls, the RBC routes are littered with the corpses of Cells who failed to complete their tasks, and threats are much more violent and frequent than in the original material.
- Cells at Work and Friends! is a Shōjo Spin-Off of Cells at Work! that maintains the character and intercellular dynamics of its source material, but it's a character-driven comedy focusing on a Killer T Cell who wants to make friends and embrace his softer side...if only his sense of duty and need to keep up his overly manly, badass reputation would stop getting in the way. While much less action-oriented and biology lesson-oriented than the original series, And Friends remains mostly scientifically accurate, despite some odd departures like showing the cell-people consuming human food rather than bacteria, glucose, or other applicable bodily chemicals.
- Cells NOT at Work! is another comedic Spin-Off of Cells at Work!, this time focusing on a Macrophage who attempts to raise and train a bunch of young Red Blood Cells...who are all young adults who refuse to grow up and embrace their job as Red Blood Cells. In a universe where characters' very lives are defined by the purpose they serve, this is a problem. While it boasts a much narrower focus than its parent series, this manga also embraces its Edutainment label and contains a lot of accurate information about macrophages and the life cycle of red blood cells.
- An Otome Game Ota plays in Wasteful Days of High School Girls runs of this, by turning different organs into Bishōnen.
- Suske en Wiske: In "De Slimme Slapjanus",when Suske, Wiske and Lambik have to go on a "Fantastic Voyage" Plot in Jerom's body, professor Barabas gives them special goggles that allow them to see the bloodcells, bacteria and virusses as humanoid creatures, and thus interact with them.
- The UK Wicked Willie comic books are about a man's anthropomorphic penis.
- Osmosis Jones: The film is a Buddy Cop story that takes place inside the body of a zookeeper. Here, we see a city populated by cells, and follow Cowboy Cop White Blood Cell Osmosis "Ozzy" Jones and his unwilling partner, the By-the-Book Cop cold pill Drix, as they are tasked with hunting down a deadly virus.
- In Fight Club, the narrator and Tyler discover a series of articles about human organs written from the perspective of the organs in first-person. "I am Jack's lungs."
- At one point briefly in 1996, Nickelodeon began to air a series of interstitial bumpers between shows titled Inside Eddie Johnson, which served as fairly low budget PSAs depicting (very loosely) the inner workings of the human body of a school-aged boy named Eddie Johnson, mainly characterized by his poor eating habits among a handful of other lessons he was indirectly taught. Bizarrely enough, these bumpers featured pretty noteworthy actors such as Susan Sarandon playing roles.
- The Fight Club example above is based on a series of real articles in Readers Digest with titles like "I am Joe's Heart". ("I am John's Heart" in the UK editions for some reason.)
- Me and My Dick takes place in a universe where people can talk to their anthropomorphized genitals (who are played by live actors, with only a few costume details indicating what they are). An anthropomorphic heart also makes an appearance, implying that there are more anthropomorphic body parts.
- Cranium Command, a show in Epcot's Wonders of Life pavilion, centered around a clumsy "Cranium Commando" soldier given the task of controlling a 12-year-old boy from the control center that is his brain. To aid him in this task, there are several organs that appear on screens to give advice and make demands—these range from the hungry Stomach, the panicky Bladder, and the overreacting Adrenal Gland.
- The Elite Beat Agents level "La La" goes inside the body of a sick track runner. There, we see a white blood cell depicted as a sexy nurse fighting off an army of demons (viruses) with a giant hypodermic needle. You have to dance to encourage her to succeed. Yeah, it's one of those games.
- Marco and the Galaxy Dragon has the titular heroines going inside of a Nudo to stop it from swallowing the Earth at one point. They encounter many sentient cells and germs as they travel through the creatures body, most of which sport ID tags. The one exception, a white blood cell, turns out to be a parasite that was controlling the Nudo from within.
- This is a key game mechanic in Mario & Luigi: Bowser's Inside Story. As the title implies, Mario and Luigi end up shrinking down and getting trapped inside Bowser, and end up assisting him on various adventures by traveling to different areas of his body. Some of those areas are populated by various sentient creatures that resemble parts of animal anatomy. For example, the Flab Zone (which develops when the Koopa king temporarily becomes obese) is run by Princess Lipid, a high-speaking blob of fat; the boss of that region is the Kretin, a monstrous keratin molecule. Other characters include the Emoglobins (a group of proteins that function as Mr. Exposition) and the Memory Neuron (a floating ball of electricity that guards Bowser's precious memories).
- The race of Gestaltians from Quentyn Quinn, Space Ranger are literally built of this trope, as they are symbiotic conglomerates of living organ systems - nervous, musculoskeletal, digestive, circulatory, etc - that bud off of sessile marine polyps and join together into a merged, sentient humanoid. On their own, these systems vary in how anthropomorphized they are, although all of them retain mobility in water at least.
- One episode of Arthur opens on anthropomorphic versions of Arthur's heart, lungs, stomach, intestines, and kidneys wondering where the brain is.
- In one episode of The Fairly OddParents, Timmy travels inside his babysitter Vickey to learn about the human body for his report, only to find, among other things, a waterslide digestive system that is managed by cells, a computer office in the brain (where he finds the deserted cubicle of Kindness), a black hole where the heart should be, and... Kidney World (founded by none other than Walt Kidney, of course).
- Family Guy: Stewie discovers his parents want to have another child and, fearing his status as the baby of the family, shrinks himself down to destroy all of Peter's sperm. While it starts out as a standard "Fantastic Voyage" Plot, it becomes this when he enters a testicle to discover that sperm cells are actually sperm-shaped fighter jets piloted by the potential children.
- Il était une fois... la Vie (Once Upon a Time... Life) is an Edutainment cartoon focusing on the human body that depicts various cells and structures as little humanoids working inside the human body, which is itself still depicted as being made up of bone and flesh. The brain is a high-tech command center, red blood cells are stout red humanoids who carry oxygen bubbles in pouches on their backs, white blood cells are security forces of various sorts, nerve cells are swift-running messengers, bacteria are orc-like invaders, viruses are sneaky, green-and-yellow wormlike critters, and so on.
- Ozzy & Drix, being the Spin-Off To Osmosis Jones (see Film, above), continues in the same vein of depicting the body as a bustling city. Only, rather than taking place in the same washed-up human as in the film, a mosquito bite causes both main characters to be taken out of their human to a teenage boy named Hectornote The show then follows both Jones and Drix as they grow accustomed to life in a teenager's body, allowing for Edutainment without it interrupting the flow of the show.
- Long before Osmosis Jones, ABC television ran a Public Service Announcement series called Time for Timer, featuring a character representing the sense of time in the human body (time to eat, sleep, etc.). Timer appeared in two movies before, but the public service announcements are much more well-known now.
- The Oh Yeah! Cartoons short "Microcops" stars a robot-like antibody cop chasing a virus bug inside a man's body. The brain is a command and control center, the bowels is a sewer, and the heart is a motor. The cop also uses an elevator system to get to the brain immediately (aka, the spinal chord).