This is an incredible animation that needs to be watched all the way through. There is a tremendous amount of detail put into simplifying the inner workings of the human body. It actually makes things much easier to understand.
In 1926, Fritz Kahn created the poster Man As Industrial Palace. as was appropriate for the Art Deco era, he depicted the human body as a factory run by little workers processing food, moving blood, and pumping engines. Henning Lederer took this idea and turned it into an animated short. From a promotional brochure for the film:
The visual crossover between industrialization and science in Fritz Kahns artwork demonstrates surprisingly accurately how human nature became culturally encoded by placing the knowledge in an industrial modernity of machine analogues. He produced lots of illustrations that drew a direct functional analogy between human physiology and the operation of contemporary technologies. Therefore, by illustrating the body as a factory, Kahn was able to relate the bodys complex organic interior to the industrialized space so common in society during that period of time (the poster was created in 1926).