The Magic School Bus - Inside Ralphie (Also on Netflix)
 
In this fun little Magic School Bus video, kids can learn all about the immune system and how the body fights off germs—by taking a trip down into the body’s fortress itself and meeting the internal soldiers that keep us safe. This episode will surely keep kids engaged as they learn through simplified language and clear explanations, all while following the story of the beloved Ms. Frizzle and her class. 
 
“The class needs Ralphie to give them a story idea for broadcast day, but Ralphie is sick. His mother, a doctor, refuses to allow him to go to school. When Ms. Frizzle says that there is an amazing battle going on inside him, the class decides broadcast day should be about whatever is making Ralphie sick. After shrinking and going into Ralphie's veins through a cut, the class travels to Ralphie's sore throat to see what is making him sick.”