HISTORY AND BACKGROUND
The history of physiology can be traced back to the ancient civilizations of India and Egypt, where it was first studied by Hippocrates (referred to as the “father of medicine”) in the year 420 BC.
Claudius Galenus (130-200 AD) was the first to conduct experimentation on the systems of the body. Hence, he is referred to as the founder of experimental physiology.
It was Jean Fernel (1497-1558), a French physician, who first introduced the term “physiology,” from an Ancient Greek word meaning “study of nature, origins.”
Harvey was the first to explain how blood moves from the heart to the brain and other body systems, as well as the circulatory system. An Anatomical Dissertation Upon the Movement of the Heart and Blood in Animals, written by William Harvey, was published in 1628 and marked a significant advance in the history of physiological science.
The arrival of Matthias Schleiden and Theodor Schwann’s cell theory in 1838, which proposed that the body is composed of minuscule individual cells, marked a paradigm shift in thinking.
From here, the study of physiology developed and advanced swiftly:
Joseph Lister (1858) discovered life-saving antiseptics while first researching coagulation and inflammation following an injury.
Dogs’ conditioned physiological responses were studied by Ivan Pavlov in 1891.
The discovery of how capillaries regulate blood flow earned August Krogh the Nobel Prize in 1920.
The ionic mechanism responsible for nerve impulse transmission was identified in 1952 by Andrew Huxley and Alan Hodgkin.
Physiologists did not distinguish between animal and medical physiology until the twentieth century. The majority of physiological tests on animals were conducted with the purpose of better understanding the human body in both health and disease. However, throughout the twentieth century, biologists grew interested in applying newly developed physiological knowledge to animals living in a variety of settings, as well as in attempting to understand the nature of physiological diversity.
Per Scholander (1905-1980) was a pioneering and prominent comparative physiologist. Scholander investigated a wide range of physiological reactions, including the mechanisms involved in diving vertebrates, warm-blooded animals’ adaptations to cold surroundings, and how fish fill their swim bladders (air-filled organs used for buoyancy). In the study program detailed in the opening essay of this chapter, Scholander also organized the influential Alpha Helix excursions.
C. Ladd Prosser’s (1907-2002) accomplishments include the discovery of so-called central pattern generators. Many rhythmic behaviors, including breathing and walking, are coordinated by these groupings of neurons. Prosser also established the connection between conduction speed and muscle diameter. As part of the Manhattan Project, he investigated the effects of radiation on animal life during World War II.
Knut Schmidt-Nielsen (1915-2007) dedicated his professional life to learning how animals survive in challenging and peculiar habitats. He demonstrated that the camel’s nose has a countercurrent exchanger that enables it to recover moisture from exhaled air, leading to an over 60% reduction in water loss compared to other mammals in his seminal early study on the adaptations of the camel to desert living.
The study of an organism’s interactions with its surroundings is known as ecological physiology, and it was founded by George Bartholomew (1923-2006). To evaluate the evolutionary significance of modifications or adaptations in animals to their environments, Bartholomew merged the study of animal behavior, ecology, and physiology. He stressed the significance of variety in physiology and recognized the individual as the primary unit of natural selection.
The topic of adaptational biochemistry was founded by George Somero (1941-) and Peter Hochachka (1937-2002). They have expanded our understanding of how animals adapt to harsh environments at the subcellular level by applying the ideas and methods of biochemistry to questions of comparative physiology. This has given rise to new insights into the biochemical mechanisms that enable animals to live in a variety of habitats, including the deep sea, the Antarctic oceans, high mountain peaks, and tropical rain forests.
The importance of physiology was acknowledged by the 1901 Nobel Prize in Physiology or Medicine. Emil von Behring’s ground-breaking research on the treatment of tetanus and diphtheria earned him the first Nobel Prize in Physiology or Medicine. He injected healthy animals with weakened strains of the germs that caused these ailments, and the animals’ immune systems rendered the bacterial poisons inert. He then administered this blood serum to the sick animals. Treatment of the infection’s symptoms prevented the sick animals from dying of their illnesses. In the end, this was applied to humans, saving many lives.
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