Overview
The lecture explores the influential legacy of Galen in medicine, his discoveries and misconceptions, and how later anatomists like Vesalius challenged his long-standing authority.
Galen’s Background and Influence
- Galen was born in 129 CE and sought medical knowledge around the Mediterranean.
- He became a skilled surgeon, performing public anatomy demonstrations to showcase his expertise.
- Galen served as a surgeon to gladiators and later became the physician to four Roman Emperors.
- His extensive writings dominated Western medicine for over 1,300 years.
Galen’s Contributions to Anatomy and Medicine
- Galen believed each organ had a specific function and conducted animal dissections due to bans on human cadavers.
- He correctly determined the brain controls the body, not the heart.
- He distinguished between sensory and motor nerves.
- Galen established that urine is produced by the kidneys and that respiration is regulated by muscles and nerves.
Key Mistakes and Misconceptions
- Galen incorrectly thought blood was produced in the liver and used up in one-way flow to organs.
- He supported the theory of the Four Humours, believing health relied on balancing four bodily fluids.
- Treatments like bloodletting and purging, based on this theory, were often harmful.
Impact of Galen’s Legacy
- Galen’s authority persisted, with his texts central to medical education for centuries.
- Doctors repeated his mistakes, ignoring contradictory evidence from human dissections.
- Opposing views were often dismissed or ridiculed.
The Challenge by Vesalius
- In the 16th century, Vesalius discovered errors in Galen’s anatomy, many based on animals, not humans.
- Vesalius publicly challenged Galen’s authority, sparking gradual changes in medicine.
- Accurate understanding of blood circulation and abandonment of the Four Humours took another 100–200 years.
Key Terms & Definitions
- Anatomy — the study of the structure of living things.
- Four Humours — ancient theory that health is governed by four bodily fluids: blood, phlegm, yellow bile, black bile.
- Bloodletting — medical practice of withdrawing blood to treat illness.
- Sensory nerves — nerves that transmit signals from the body to the brain.
- Motor nerves — nerves that carry commands from the brain to muscles.
Action Items / Next Steps
- Review the contributions and mistakes of Galen for a clear understanding of the evolution of medical knowledge.
- Read about Andreas Vesalius and further advances in anatomy.