Rudolf Fränkel was a person who lived a long time ago. He was interested in science and was especially curious about how our bodies work. Rudolf studied different cells that make up our bodies, like the ones in our brains that help us think and feel.
He was especially interested in how these cells communicate with each other, sort of like how people talk to each other to share information. Rudolf discovered that cells use special chemicals called neurotransmitters to talk to each other and send messages.
He also found out that some illnesses, like Parkinson's disease, happen when some of these cells stop working properly. This can make it hard for the brain to send messages to our bodies, which can cause problems like trouble moving.
Even though Rudolf did this research a long time ago, his discoveries are still really important for scientists today who are working to understand how our bodies work and how to treat diseases.