Physiology
Physiology is the scientific study of functions and mechanisms in a living system. It focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and physical functions. The field spans from the molecular level to whole populations. Anatomy provides knowledge of structure and organization at all levels. Biochemistry studies chemical processes within living organisms. Biophysics examines physical properties and interactions with the environment. Genetics explores heredity and variation of traits. Evolutionary biology explains the origin and adaptive significance of physiological processes.
The study of human physiology as a medical field originates in classical Greece during the late 5th century BC. Hippocrates incorporated the theory of humorism involving four basic substances: earth, water, air and fire. Each substance corresponds to a humor: black bile, phlegm, blood, and yellow bile. Galen lived until 200 AD and was the first to use experiments to probe body functions. He argued that humoral imbalances can be located in specific organs including the entire body. Galen saw the human body consisting of three connected systems: the brain and nerves for thoughts, the heart and arteries for life, and the liver and veins for nutrition. For the next 1,400 years Galenic physiology remained a powerful tool in medicine.
Jean Fernel introduced the term physiology between 1497 and 1558. Luigi Galvani described electricity's role in frog nerves in 1791. César Julien Jean Legallois studied respiration in animal dissection in 1811. Charles Bell finished work on what became known as the Bell, Magendie law in 1811. François Magendie described sensory roots in 1824. Henri Milne-Edwards introduced physiological division of labor in the 1820s. Joseph Lister studied blood coagulation in 1858. The Physiological Society founded in London in 1876 began as a dining club. Ivan Pavlov performed research on conditional responses involving dogs' saliva production in 1891. August Krogh won the Nobel Prize in 1920 for discovering how capillaries regulate blood flow. Andrew Huxley and Hugh Huxley discovered sliding filaments in skeletal muscle in 1954.
Physiology divides into medical, animal, plant, cell, and comparative categories based on organism classes. Subdisciplines exist by taxa including human, animal, plant, microbial, and viral physiology. They also categorize by organizational level: cell, molecular, systems, organismal, ecological, and integrative physiology. Research objectives split applied fields like medical physiology from non-applied areas such as comparative physiology. Plant physiology concerns photosynthesis, respiration, nutrition, tropisms, and stomata function. Animal physiology includes nervous, endocrine, cardiovascular, respiratory, digestive, and urinary systems. Human physiology seeks to understand mechanisms keeping the body alive through mechanical, physical, and biochemical functions. Comparative physiology considers functional diversity across organisms.
Initially women were largely excluded from official involvement in any physiological society. The American Physiological Society founded in 1887 included only men in its ranks. Ida Hyde became the first female member of that society in 1902. On the 3rd of July 1915 six women were officially admitted to The Physiological Society: Florence Buchanan, Winifred Cullis, Ruth Skelton, Sarah C. M. Sowton, Constance Leetham Terry, and Enid M. Tribe. Bodil Schmidt-Nielsen became the first woman president of the American Physiological Society in 1975. Gerty Cori received the Nobel Prize in 1947 for discovering glycogen's phosphate-containing form. Barbara McClintock won an unshared Nobel Prize in 1983 for genetic transposition discovery. Françoise Barré-Sinoussi shared the 2008 Nobel Prize for identifying HIV as the cause of AIDS.
Claude Bernard lived between 1813 and 1878 and developed his concept of milieu interieur or internal environment. Walter B. Cannon championed homeostasis in 1929 meaning maintenance of steady states in the body. Cannon defined it as physiological processes through which they are regulated. Homeostasis represents the body's ability to regulate its internal environment. Changes in physiology can impact mental functions of individuals. Examples include effects of certain medications or toxic levels of substances. Change in behavior resulting from these substances often assesses individual health. The endocrine and nervous systems play major roles in signal reception and transmission integrating function in animals. Integration refers to overlap of many functions within human body systems achieved through electrical and chemical communication.
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Common questions
What is the definition of physiology in science?
Physiology is the scientific study of functions and mechanisms in a living system. It focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and physical functions.
When did the study of human physiology originate in classical Greece?
The study of human physiology as a medical field originates in classical Greece during the late 5th century BC. Hippocrates incorporated the theory of humorism involving four basic substances: earth, water, air and fire.
Who introduced the term physiology between 1497 and 1558?
Jean Fernel introduced the term physiology between 1497 and 1558. Luigi Galvani described electricity's role in frog nerves in 1791 and César Julien Jean Legallois studied respiration in animal dissection in 1811.
How many women were officially admitted to The Physiological Society on the 3rd of July 1915?
On the 3rd of July 1915 six women were officially admitted to The Physiological Society: Florence Buchanan, Winifred Cullis, Ruth Skelton, Sarah C. M. Sowton, Constance Leetham Terry, and Enid M. Tribe. Ida Hyde became the first female member of the American Physiological Society in 1902.
What is homeostasis according to Walter B. Cannon in 1929?
Walter B. Cannon championed homeostasis in 1929 meaning maintenance of steady states in the body. Homeostasis represents the body's ability to regulate its internal environment through physiological processes.