The basic idea for the development of physiology was the requirements of medicine. The ancients had considerable interest in physiology as they realized that it is impossible to cure a disease without knowing the structure “of the body of the organism and the functions of its organs.
The physicians of ancient Greece and Rome tried to obtain an idea about the activities or the functions of the different organs of the body, but their conclusions were neither systematic nor scientific as they were based entirely on speculative reasoning resulting mainly from a study of the rough structure of those organs.
Physiology in 17th century:
The 17th century is regarded as the date of the foundation of physiology, it is because one of the most essential function of the organism was investigated for the first time.
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William Harvey was the first who in 1628, investigated the most important activity of the body-the circulation of the blood.
In 1661, Malpighi discovered the capillaries. Due to lack of good apparatuses and techniques further investigations could not be made and thus physiology could not flourish more in the 17th century.
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Physiology in 18th century:
In the 18th century there were great advances in various fields of physiology which provided the foundation for its further development.
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St. Hales was the first who in 1732 measured the blood pressure in the arteries. Bernoulli in 1738 observed the movement of fluids in the body and laid down the foundation of further haemodynamics.
Borelli pointed out the movements of thorax during the process of respiration, particularly in higher animals. In 1753, Lind gave the idea of certain substances, now called hormones, which regulate the different activities of the body.
In 1777, Reamur and Spallanzani discovered the functions and properties of gastric juice secreted by the stomach cells or glands.
P. Zagorsky studied the vascular system. Whytt discovered the theory of reflex action and he showed that after the destruction of central nervous system, a frog no longer responds to external stimuli.
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The most important discovery of the physiology in 18th century was the application of the laws of inanimate nature, the laws of chemistry to processes taking place in the body of organism.
Mikhail Lomonosov investigated the law of constancy of matter and motion and formulated the kinetic theory of the structure of matter. He also proved that air is a mixture of various gases.
Lavoisier gave the idea of respiration as the showed that the oxidation of organic compounds of the body is carried out by the oxygen present in the air. Later Lavoisier and Laplace demonstrated that oxidative processes yield same amount of heat both during the oxidation of “carbonic combustions” in the organism and during their combustion outside the organism.
The concept of irritability was also originated in the 18th century. Francis Glisson was the man who gave irritability concept. Johannes, Muller and Marshall proposed the theory of reflex action.
Thus in the end of 18th century physiology has accumulated certain facts concerning blood circulation and respiration.
In that time it was already in a position to make use of scientific data on the microscopic structure of various organs.
Physiology in the 19th century:
Great advances came in every field of physiology in the 19th century. The subsequent development of physiology was determined by new methods of scientific observations by the general development of science.
Among the most distinguished 19th century scientists who worked in physiology are Takaki, Eijkmann, Webber, Pfluger, Bichat, Magendie, Bell, A. Filomofitsky, Plesgaft, V. Basoy and S. Botkin.
Some of them made discovery in the physiology of endocrines, some in blood and blood-circulation, some in digestion and still others in respiration and nervous system.
Before the middle of 19th century it had taken us a full fledged branch of science. In the same century three great discoveries were made in the natural science, the law of conservation of energy, the cellular theory and the theory of evolution, which brought the swift progress in all biological sciences including physiology.
Helmholtz, Ludwig, Marey and others tried to find out the facts that how do muscles contract and how impulses are travelled along the nerve fibre.
Meyer, Pfluger, Pashutin and Likhachov discovered the law of conservation and transformation of energy which made the physiology to arrive at a quantitative description of physiological processes from the aspect of energy-loss and energy-accumulation.
In the second half of the 19th century physiology attained great success as many great discoveries were made in that period.
Claude Bernard as early as 1859 pointed out that complex organisms live in two environments-an external environment and an internal environment which surrounds the cells and tissues of the body, is characteristic of the animal species and remains relatively constant and serves as medium for the exchange of foods and wastes and for the distribution of chemical messengers.
Webber (1860), Pfluger (1900) tried to observe the mechanism of absorption. Webber, Bezold, Cyon and Pavlov investigated the influence of nervous system on the heart. Bernard, Ludwig, Walther and OvsyannikoV tried to observe the influence of nervous system on the blood vessels.
Magendie, Helmholtz, Wedensky studied the influence of nervous system on the skeletal muscles, while Pfluger, Mislavsky and Langly studied the influence of nervous system on smooth muscles of the alimentary canal.
In the end of 19th century Pavlov investigated the most important concept of digestion. Dubois and Reymond investigated the electrical phenomena in nerves and muscles, the work which was already started in the 18th century by Galvani.
Hermann and Wedensky gave the concept of nerve impulse. Nentsky and Pavlov studied the transformation of products of metabolism in the liver.
Physiology in 20th century:
In the 20th century physiology had reached at the peak of its development. With the development of sophisticated instruments and techniques the various problems of structure and functions of different organs of the organism are being elaborated by modern scientists.
The characteristic feature of latest scientific research is that it is conducted on a molecular, sub-microscopic and cellular level. For this purpose very fine and complex experiments and methods are used.
These experiments and methods make it possible to study processes occurring in the cell and in the various structures which form part of the cell. In the 20th century all the aspects of physiology have been studied by the modern scientists.
Bayliss and Starling, later Gabriel and Fogel, in 1902, discovered the first hormone called secretin produced by the wall of the alimentary canal. S. Gyorgyi, Welsh 1957, Gorbman and Bern 1962, Barrington 1963, Von Euler, Heller 1963, also discovered certain neurosecretory substances and hormones.
Langly 1921 discovered the concept of autonomic nervous system. Hyman 1951, Andrew 1959, Morton 1960 gave the information about the movements of the gut contents in different animals.
Yonge 1937, Owen 1950, Nigol 1960, Barrington 1962, discovered various types of feeding habits in animals. Schilling 1902, Van Herwerden 1908, Green 1912, Frazer 1940 and Mellanby described the mechanism of absorption.
Bard 1961, Carter, Whitford and Hutchinson 1963, Foxon 1964 elaborated the knowledge of the process of respiration.
Rudd 1954, Fox, Vevers 1960, Manwell 1960, Gratzer and Allison 1960, Anthony 1961 discovered the transportation of respiratory gases, e.g., O. and CO2. Needham 1931, Sumner 1951, Smith 1953, Krebs, Cohen and Brown 1960, Prosser and Brown 1961, Balwin 1963, discovered the various aspects of the process of excretion in different animals.
Verworn 1899, Heilbrunn 1953, Bernard and Bayliss elaborated the various aspects of the concept of irritability which was already originated by Francis Glisson in the 17th century.
Szent Gyorgyi 1944, Inoue 1959, Hoffman, Berling 1960, Satir 1961, Hoyle, Allen 1961, Lehninger 1962, Perutz 1964 and Rinaldi discovered the various activities of the effector organs including muscles and nerves. In this way the various aspects have been studied by the modern scientists. Now physiology has made its independent existence amongst biological sciences.