This clip explores the structure of the human skin to explain how wounds heal in four main stages: Hemostasis, Inflammation, Proliferative, and Remodeling.

Joey shows his unhealthy eating habits in these clips. He will eat whatever is in front of him, no matter the combination of food or how old it is.

Lack of heating, proper washing, and hygeine caused many to grow sick at a fast rate. Without medicine, people had a high mortality rate and died at an early age from disease or viruses, especially nemonia or sedintary.

Michael explains how anesthesia works. He discusses how even though we've used anesthesia for decades we haven't completely understood how it works until recently.

After taking estrogen, Howard asks Raj if his body is changing.They figure it out with some unusual methods.