Once Upon a Time... Life(1987)

Seimei no Kagaku: Micro Patrol

The series "Once Upon a Time... Life" teaches about the human body and about the different systems in it with the same characters from the other "Once Upon a Time" seasons. "The good Characters" represent the body's defense mechanisms, whereas "the bad Characters" represent the viruses and bacteria that threaten to attack the human body.

(Source: Wikipedia)