Photos of a Nanjing medical school professor have become hugely popular online. In the photos, the professor can be seen teaching without a shirt on in front of the class, using his own body to explain the lesson. Many students say he has changed their views on teaching.

The professor, named Li Lei, teaches human anatomy at Nanjing Medical University in Nanjing, Jiangsu province. While teaching, Li often becomes so enthusiastic that he lifts up his own clothes in order to demonstrate to students the exact locations of different organs in the human body.

Li has had an undeniable influence on a number of his students. One freshman reported feeling proud of herself after drawing various muscles directly on her upper arm for a more visual study. A doctor at a hospital in Nanjing said he still clearly remembers Li's classes, even though he graduated 10 years ago.

Li said he adopted his special teaching method after hundreds of experiments.