Arnold's Small Intestine is the fourth part of Arnold's digestive system where Ms. Frizzle and her class travel through on their field trip of there in The Magic School Bus episode, For Lunch. They traveled through it again in Goes Cellular.
History[]
For Lunch[]
Now a submarine, the bus swims through the digestive juices in the small intestine. Tim states that this reminds him of Scuba World, and Ms. Frizzle suggests going for a dive, much to Phoebe's dismay. Wanda sees the gum Arnold swallowed and swims off to chase it. Carlos notices that the villi of the small intestine are soaking up the food. Dorothy Ann gives a "United Digestion" presentation on how the small intestine absorbs nutrients into the bloodstream. Wanda is seen balancing on the top of the gum as it catapults into a valve in the intestinal wall.
The class begins looking for Wanda, and stumbles upon the valve. Ms. Frizzle realizes she was sent to Arnold's large intestine. The bus swims in to save Wanda, sucking the class into the valve sending them to the large intestine. Later, the class returns to the small intestine on the way out of Arnold's body, swimming back into his stomach.
Goes Cellular[]
When Ms. Frizzle takes the class except Phoebe back into Arnold's small intestine, they notice the villi cells and go into his bloodstream to see what made his skin orange.