ORIGINS AND GROWTH OF PHYSIOLOGY

The term “Physiology” derives from the Greek words ‘PHYSIS’ (meaning “nature, origin”) and ‘LOGIA’ (meaning “study of”). Thus, physiology, as a subdiscipline of biology, is the study of the functions and mechanisms of living organisms.

In ancient Greece, the studies of human physiology as a medical field by Hippocrates (460-370 BCE) led to his recognition as the “Father of Medicine.” Aristotle (384-322 BCE) made critical contributions through his focus on the relationships between structure and function, as observed in his animal dissections. Galen (129-216 CE) conducted extensive anatomical dissections on animals and was among the first to describe the circulatory system. However, some of his conclusions based on animal dissection led to inaccurate applications to human physiology. Even so, the influence of Galen’s writings and philosophy on physiology remained dominant until the 16th century.

In the 1500s, a French physician, Jean Fernel (1487-1558), introduced the term “physiology” to describe the study of the body’s function. Andreas Vesalius (1514-1564), a Belgian physician conducting research in Italy, made significant advances on Galen’s animal dissections by carrying out numerous dissections on human cadavers. The detailed anatomical illustrations published by Vesalius in 1543 laid the foundation for a more accurate understanding of human physiology. Another important contributor to physiological knowledge was the English physician, William Harvey (1578-1657). He was the first to describe the circulatory system and how the heart pumped blood throughout the body.

During the 18th and 19th centuries, physiology emerged as a distinct scientific discipline in which experimental methods became increasingly important. Albrecht von Haller (1708-1777), a Swiss physician, conducted numerous experiments to distinguish between nerve impulses and muscular contractions. He described these and other experiments in an eight-volume encyclopedic “Physiological Elements of the Human Body” (1757-1766). The experiments conducted by Luigi Galvani (1737-1798), an Italian physician, provided evidence of the electrical nature of nerve impulses.

Joseph Lister (1827-1912) was an English surgeon, medical scientist, and experimental pathologist. The results of his physiological experiments on the mechanism of blood coagulation and the role of blood vessels in the first stages of inflammation were published in seven papers in 1858. Lister is also recognized as the founder of antiseptic medicine, based on the experiments he conducted to reduce infection in wounds and during surgery.

The French physiologist Claude Bernard (1813-1878) is often considered to be the “father of experimental physiology.” He is best known for his discoveries on the role of the pancreas in digestion, the glycogenic function of the liver, and the regulation of the blood supply by the vasomotor nerves. Bernard originated the concept of “milieu intérieur” (internal environment), which later became known as homeostasis. Throughout his career, he sought to establish the importance of using the “scientific method” to understand the normal functioning of the body. In Germany, Carl Ludwig (1816-1895) established the Institute of Physiology in Leipzig, which was more closely associated with universities than with hospitals. Government sponsorship allowed him to provide excellent laboratories and develop new laboratory equipment.

Sir Michael Foster (1836-1907) was an English physiologist and professor at the University of Cambridge who introduced modern methods of teaching physiology, emphasizing laboratory experimentation. Although he was not highly distinguished by his own research, his laboratory produced many leading physiologists in the late 19th century. Foster published a major physiology textbook in 1877 and was instrumental in founding the Physiological Society in 1876 and the Journal of Physiology in 1878. The Society is the oldest and largest network of physiologists in Europe and now has members from over 60 countries.

While physiological research in Europe and England flourished before 1870, American physiological research lacked the institutional framework to support research. Physiology instruction and practice were limited, occurring in varying amounts in small, private, proprietary schools run by practicing physicians. No set curriculum or exit standards were in place across schools. Only a few U.S. medical schools affiliated with universities provided opportunities for MD degree candidates to perform physiology research. Thus, to further develop American physiology as a full-time occupation, young American investigators often traveled abroad to the laboratories of Bernard, Ludwig, and Foster to gain research skills and experience.

In 1887, 28 American doctors and scientists founded the American Physiological Society (APS) to promote the advancement of physiology and facilitate interaction among American physiologists. Five of the 28 charter members were considered the founders of APS. Henry Bowditch (1840-1911) of Harvard University was elected the first President of APS. He had attended Bernard’s lectures in Paris and conducted research in Ludwig’s laboratory in Germany. Henry Martin (1848-1896), an Irish-born student of Foster at Cambridge University, was elected as the first Secretary of APS. At Johns Hopkins University, Martin was known as an exceptional teacher of physiology and a brilliant experimentalist. A third founder of APS, Silas Mitchell (1848-1896), also had attended Bernard’s physiology lectures in Paris. Upon his return, he established a small research laboratory at his home and then became the lead Union physician during the Civil War. The other two founders of APS were
John Curtis (1844-1913), who taught physiology at the College of Physicians and Surgeons in New York City, and Russell Chittenden (1856-1943), who established a physiology laboratory at Yale University.

Of the original 28 founding members of APS, five had trained with Bowditch, and ten had been trained by or were associated with Martin at Johns Hopkins University. A total of 22 of the 28 founding members had studied abroad, with most (9) receiving their training in Germany.

During the 20th century, physiological discoveries experienced rapid growth, particularly in Europe, the United Kingdom, and the United States. Advances in technology supported the development of molecular biology, genetics, and imaging techniques, allowing physiologists and physicians to study bodily functions with greater precision. Physiological research has become increasingly multidisciplinary, incorporating elements from other sciences, such as biochemistry, computer modeling, and physics.

Physiology is recognized as the foundation of all medical sciences and remains central to
understanding health, disease, and therapeutic interventions. The Nobel Prize in Physiology or Medicine was first awarded in 1901, and a total of 232 individuals have received this award through 2025. Some of the physiology research discoveries that have been honored with this Nobel Prize include those related to the nervous system (neurotransmitters), genetics (DNA, RNA), cellular processes (metabolism, molecular pathways), the immune system (T cells), and the endocrine system (insulin).

The discipline of physiology has given rise to numerous subdisciplines. These can be categorized into major subdivisions: by level of organization (cell, molecular, systemic, organismal physiology); by specific systems/functions (nerve, endocrine, vision, cardiovascular, renal, respiratory physiology); by application and context (comparative, clinical, environmental, pathology, exercise physiology); and other specialized areas. (mathematical, nutritional physiology).

American Physiological Society, “History & Founders,”
https://www.physiology.org/about/welcome/Founders?SSO=Y

Bernstein, Larry H., “Highlights in the History of Physiology,”
https://pharmaceuticalintelligence.com/2014/12/28/highlights-in-the-history-of-physiology/

Britannica, “Physiology,” https://www.britannica.com/science/physiology

History of Physiology, iWorx Systems, Inc., https://iworx.com/history-of-physiology/?v=0b3b97fa6688

Physiology, Wikipedia, https://en.wikipedia.org/wiki/Physiology