Through his vivisection practices, Galen also proved that the voice was controlled by the brain. One of the most famous experiments that he recreated in public was the squealing pig: Galen would cut open a pig, and while it was squealing he would tie off the recurrent laryngeal nerve, or vocal cords, showing they controlled the making of sound. He used the same method to tie off the ureters to prove his theories of kidney and bladder function. Galen believed the human body had three interconnected systems that allowed it to work. The first system that he theorized consisted of the brain and the nerves, responsible for thought and sensation. The second theorized system was the heart and the arteries, which Galen believed to be responsible for providing life-giving energy. The last theorized system was the liver and veins, which Galen theorized were responsible for nutrition and growth. Galen also theorized that blood was made in the liver and sent out around the body.
Through his vivisection practices, Galen also proved that the voice was controlled by the brain. One of the most famous experiments that he recreated in public was the squealing pig Galen would cut open a pig, and while it was squealing he would tie off the recurrent laryngeal nerve, or vocal cords, showing they controlled the making of sound. He used the same method to tie off the ureters to prove his theories of kidney and bladder function. Galen believed the human body had three interconnected systems that allowed it to work. The first system that he theorized consisted of the brain and the nerves, responsible for thought and sensation. The second theorized syste:m was the heart and the arteries, which Galen believed to be responsible for providing life-giving energy. The! last theorized system was the liver and veins, which Galen theorized were responsible for nutrition and growth. Galen also theorized that blood was made in the liver and sent out around the body.