|Part of a series on|
Physiology ( /ˌfɪziˈɒlədʒi/ ; from Ancient Greek φύσις (phúsis) 'nature, origin',and -λογία ( -logía ) 'study of')  is the scientific study of functions and mechanisms in a living system.   As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical and physical functions in a living system.  According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology. 
Central to physiological functioning are biophysical and biochemical processes, homeostatic control mechanisms, and communication between cells.  Physiological state is the condition of normal function. In contrast, pathological state refers to abnormal conditions, including human diseases.
The Nobel Prize in Physiology or Medicine is awarded by the Royal Swedish Academy of Sciences for exceptional scientific achievements in physiology related to the field of medicine.
Physiology is the branch of biology that focuses on the study of the functions and mechanisms of living organisms, from the molecular and cellular level to the level of whole organisms and populations. The foundations of physiology lie in several key areas, including anatomy, biochemistry, biophysics, genetics, and evolution.
Anatomy is the study of the structure and organization of living organisms, from the microscopic level of cells and tissues to the macroscopic level of organs and systems. An understanding of anatomy is essential for understanding the physiological functions of organisms, as the structure of an organism often dictates its function.
Biochemistry is the study of the chemical processes and substances that occur within living organisms. It provides the foundation for understanding the metabolic processes that are essential for life, such as the conversion of food into energy and the synthesis of molecules necessary for cellular function.
Biophysics is the study of the physical properties of living organisms and their interactions with the environment. It helps to explain how organisms sense and respond to different stimuli, such as light, sound, and temperature, and how they maintain homeostasis, or a stable internal environment.
Genetics is the study of heredity and the variation of traits within and between populations. It provides insights into the genetic basis of physiological processes and the ways in which genes interact with the environment to influence an organism's phenotype.
Evolutionary biology is the study of the processes that have led to the diversity of life on Earth. It helps to explain the origin and adaptive significance of physiological processes and the ways in which organisms have evolved to cope with their environment.
Together, these foundational areas provide the basis for understanding the functions and mechanisms of living organisms at all levels of organization, from the molecular to the ecological.
Although there are differences between animal, plant, and microbial cells, the basic physiological functions of cells can be divided into the processes of cell division, cell signaling, cell growth, and cell metabolism.[ citation needed ]
Plant physiology is a subdiscipline of botany concerned with the functioning of plants. Closely related fields include plant morphology, plant ecology, phytochemistry, cell biology, genetics, biophysics, and molecular biology. Fundamental processes of plant physiology include photosynthesis, respiration, plant nutrition, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, seed germination, dormancy, and stomata function and transpiration. Absorption of water by roots, production of food in the leaves, and growth of shoots towards light are examples of plant physiology. 
Human physiology is the study of how the human body's systems and functions work together to maintain a stable internal environment. It includes the study of the nervous, endocrine, cardiovascular, respiratory, digestive, and urinary systems, as well as cellular and exercise physiology. Understanding human physiology is essential for diagnosing and treating health conditions and promoting overall wellbeing.
It seeks to understand the mechanisms that work to keep the human body alive and functioning,  through scientific enquiry into the nature of mechanical, physical, and biochemical functions of humans, their organs, and the cells of which they are composed. The principal level of focus of physiology is at the level of organs and systems within systems. The endocrine and nervous systems play major roles in the reception and transmission of signals that integrate function in animals. Homeostasis is a major aspect with regard to such interactions within plants as well as animals. The biological basis of the study of physiology, integration refers to the overlap of many functions of the systems of the human body, as well as its accompanied form. It is achieved through communication that occurs in a variety of ways, both electrical and chemical. 
Changes in physiology can impact the mental functions of individuals. Examples of this would be the effects of certain medications or toxic levels of substances.  Change in behavior as a result of these substances is often used to assess the health of individuals.  
Much of the foundation of knowledge in human physiology was provided by animal experimentation. Due to the frequent connection between form and function, physiology and anatomy are intrinsically linked and are studied in tandem as part of a medical curriculum. 
Involving evolutionary physiology and environmental physiology, comparative physiology considers the diversity of functional characteristics across organisms. 
The study of human physiology as a medical field originates in classical Greece, at the time of Hippocrates (late 5th century BC).  Outside of Western tradition, early forms of physiology or anatomy can be reconstructed as having been present at around the same time in China,  India  and elsewhere. Hippocrates incorporated the theory of humorism, which consisted of four basic substances: earth, water, air and fire. Each substance is known for having a corresponding humor: black bile, phlegm, blood, and yellow bile, respectively. Hippocrates also noted some emotional connections to the four humors, on which Galen would later expand. The critical thinking of Aristotle and his emphasis on the relationship between structure and function marked the beginning of physiology in Ancient Greece. Like Hippocrates, Aristotle took to the humoral theory of disease, which also consisted of four primary qualities in life: hot, cold, wet and dry.  Galen (c. 130–200 AD) was the first to use experiments to probe the functions of the body. Unlike Hippocrates, Galen argued that humoral imbalances can be located in specific organs, including the entire body.  His modification of this theory better equipped doctors to make more precise diagnoses. Galen also played off of Hippocrates' idea that emotions were also tied to the humors, and added the notion of temperaments: sanguine corresponds with blood; phlegmatic is tied to phlegm; yellow bile is connected to choleric; and black bile corresponds with melancholy. Galen also saw the human body consisting of three connected systems: the brain and nerves, which are responsible for thoughts and sensations; the heart and arteries, which give life; and the liver and veins, which can be attributed to nutrition and growth.  Galen was also the founder of experimental physiology.  And for the next 1,400 years, Galenic physiology was a powerful and influential tool in medicine. 
Jean Fernel (1497–1558), a French physician, introduced the term "physiology".  Galen, Ibn al-Nafis, Michael Servetus, Realdo Colombo, Amato Lusitano and William Harvey, are credited as making important discoveries in the circulation of the blood.  Santorio Santorio in 1610s was the first to use a device to measure the pulse rate (the pulsilogium), and a thermoscope to measure temperature. 
In 1791 Luigi Galvani described the role of electricity in nerves of dissected frogs. In 1811, César Julien Jean Legallois studied respiration in animal dissection and lesions and found the center of respiration in the medulla oblongata. In the same year, Charles Bell finished work on what would later become known as the Bell–Magendie law, which compared functional differences between dorsal and ventral roots of the spinal cord. In 1824, François Magendie described the sensory roots and produced the first evidence of the cerebellum's role in equilibration to complete the Bell–Magendie law.
In the 1820s, the French physiologist Henri Milne-Edwards introduced the notion of physiological division of labor, which allowed to "compare and study living things as if they were machines created by the industry of man." Inspired in the work of Adam Smith, Milne-Edwards wrote that the "body of all living beings, whether animal or plant, resembles a factory ... where the organs, comparable to workers, work incessantly to produce the phenomena that constitute the life of the individual." In more differentiated organisms, the functional labor could be apportioned between different instruments or systems (called by him as appareils). 
In 1858, Joseph Lister studied the cause of blood coagulation and inflammation that resulted after previous injuries and surgical wounds. He later discovered and implemented antiseptics in the operating room, and as a result, decreased death rate from surgery by a substantial amount. 
The Physiological Society was founded in London in 1876 as a dining club.  The American Physiological Society (APS) is a nonprofit organization that was founded in 1887. The Society is, "devoted to fostering education, scientific research, and dissemination of information in the physiological sciences." 
In 1891, Ivan Pavlov performed research on "conditional responses" that involved dogs' saliva production in response to a bell and visual stimuli. 
In the 19th century, physiological knowledge began to accumulate at a rapid rate, in particular with the 1838 appearance of the Cell theory of Matthias Schleiden and Theodor Schwann.  It radically stated that organisms are made up of units called cells. Claude Bernard's (1813–1878) further discoveries ultimately led to his concept of milieu interieur (internal environment),   which would later be taken up and championed as "homeostasis" by American physiologist Walter B. Cannon in 1929. By homeostasis, Cannon meant "the maintenance of steady states in the body and the physiological processes through which they are regulated."  In other words, the body's ability to regulate its internal environment. William Beaumont was the first American to utilize the practical application of physiology.
Nineteenth-century physiologists such as Michael Foster, Max Verworn, and Alfred Binet, based on Haeckel's ideas, elaborated what came to be called "general physiology", a unified science of life based on the cell actions,  later renamed in the 20th century as cell biology. 
In the 20th century, biologists became interested in how organisms other than human beings function, eventually spawning the fields of comparative physiology and ecophysiology.  Major figures in these fields include Knut Schmidt-Nielsen and George Bartholomew. Most recently, evolutionary physiology has become a distinct subdiscipline. 
In 1920, August Krogh won the Nobel Prize for discovering how, in capillaries, blood flow is regulated. 
In 1954, Andrew Huxley and Hugh Huxley, alongside their research team, discovered the sliding filaments in skeletal muscle, known today as the sliding filament theory. 
Recently, there have been intense debates about the vitality of physiology as a discipline (Is it dead or alive?).   If physiology is perhaps less visible nowadays than during the golden age of the 19th century,  it is in large part because the field has given birth to some of the most active domains of today's biological sciences, such as neuroscience, endocrinology, and immunology.  Furthermore, physiology is still often seen as an integrative discipline, which can put together into a coherent framework data coming from various different domains.   
Initially, women were largely excluded from official involvement in any physiological society. The American Physiological Society, for example, was founded in 1887 and included only men in its ranks.  In 1902, the American Physiological Society elected Ida Hyde as the first female member of the society.  Hyde, a representative of the American Association of University Women and a global advocate for gender equality in education,  attempted to promote gender equality in every aspect of science and medicine.
Soon thereafter, in 1913, J.S. Haldane proposed that women be allowed to formally join The Physiological Society, which had been founded in 1876.  On 3 July 1915, six women were officially admitted: Florence Buchanan, Winifred Cullis, Ruth C. Skelton, Sarah C. M. Sowton, Constance Leetham Terry, and Enid M. Tribe.  The centenary of the election of women was celebrated in 2015 with the publication of the book "Women Physiologists: Centenary Celebrations And Beyond For The Physiological Society." ( ISBN 978-0-9933410-0-7)
Prominent women physiologists include:
There are many ways to categorize the subdisciplines of physiology: 
Transnational physiological societies include:
National physiological societies include:
Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and metabolism. Over the last decades of the 20th century, biochemistry has become successful at explaining living processes through these three disciplines. Almost all areas of the life sciences are being uncovered and developed through biochemical methodology and research. Biochemistry focuses on understanding the chemical basis which allows biological molecules to give rise to the processes that occur within living cells and between cells, in turn relating greatly to the understanding of tissues and organs, as well as organism structure and function. Biochemistry is closely related to molecular biology, which is the study of the molecular mechanisms of biological phenomena.
Biology – The natural science that studies life. Areas of focus include structure, function, growth, origin, evolution, distribution, and taxonomy.
Neuroscience is the scientific study of the nervous system, its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, developmental biology, cytology, psychology, physics, computer science, chemistry, medicine, statistics, and mathematical modeling to understand the fundamental and emergent properties of neurons, glia and neural circuits. The understanding of the biological basis of learning, memory, behavior, perception, and consciousness has been described by Eric Kandel as the "epic challenge" of the biological sciences.
Zoology is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one of the primary branches of biology. The term is derived from Ancient Greek ζῷον, zōion ('animal'), and λόγος, logos.
The history of anatomy extends from the earliest examinations of sacrificial victims to the sophisticated analyses of the body performed by modern anatomists and scientists. Written descriptions of human organs and parts can be traced back thousands of years to ancient Egyptian papyri, where attention to the body was necessitated by their highly elaborate burial practices.
Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study biological phenomena. Biophysics covers all scales of biological organization, from molecular to organismic and populations. Biophysical research shares significant overlap with biochemistry, molecular biology, physical chemistry, physiology, nanotechnology, bioengineering, computational biology, biomechanics, developmental biology and systems biology.
Biomechanics is the study of the structure, function and motion of the mechanical aspects of biological systems, at any level from whole organisms to organs, cells and cell organelles, using the methods of mechanics. Biomechanics is a branch of biophysics.
The history of zoology before Charles Darwin's 1859 theory of evolution traces the organized study of the animal kingdom from ancient to modern times. Although the concept of zoology as a single coherent field arose much later, systematic study of zoology is seen in the works of Aristotle and Galen in the ancient Greco-Roman world. This work was developed in the Middle Ages by Islamic medicine and scholarship, and in turn their work was extended by European scholars such as Albertus Magnus.
Carl Ferdinand Cori, ForMemRS was a Czech-American biochemist and pharmacologist born in Prague who, together with his wife Gerty Cori and Argentine physiologist Bernardo Houssay, received a Nobel Prize in 1947 for their discovery of how the glucose derivative glycogen is broken down and resynthesized in the body for use as a store and source of energy. In 2004, both Coris were designated a National Historic Chemical Landmark in recognition of their work that elucidated carbohydrate metabolism.
Christian René Marie Joseph, Viscount de Duve was a Nobel Prize-winning Belgian cytologist and biochemist. He made serendipitous discoveries of two cell organelles, peroxisome and lysosome, for which he shared the Nobel Prize in Physiology or Medicine in 1974 with Albert Claude and George E. Palade. In addition to peroxisome and lysosome, he invented scientific names such as autophagy, endocytosis, and exocytosis in a single occasion.
Bert Sakmann is a German cell physiologist. He shared the Nobel Prize in Physiology or Medicine with Erwin Neher in 1991 for their work on "the function of single ion channels in cells," and the invention of the patch clamp. Bert Sakmann was Professor at Heidelberg University and is an Emeritus Scientific Member of the Max Planck Institute for Medical Research in Heidelberg, Germany. Since 2008 he leads an emeritus research group at the Max Planck Institute of Neurobiology.
A neuroscientist is a scientist who has specialised knowledge in neuroscience, a branch of biology that deals with the physiology, biochemistry, psychology, anatomy and molecular biology of neurons, neural circuits, and glial cells and especially their behavioral, biological, and psychological aspect in health and disease.
A biologist is a scientist who conducts research in biology. Biologists are interested in studying life on Earth, whether it is an individual cell, a multicellular organism, or a community of interacting populations. They usually specialize in a particular branch of biology and have a specific research focus.
Comparative physiology is a subdiscipline of physiology that studies and exploits the diversity of functional characteristics of various kinds of organisms. It is closely related to evolutionary physiology and environmental physiology. Many universities offer undergraduate courses that cover comparative aspects of animal physiology. According to Clifford Ladd Prosser, "Comparative Physiology is not so much a defined discipline as a viewpoint, a philosophy."
The history of biochemistry can be said to have started with the ancient Greeks who were interested in the composition and processes of life, although biochemistry as a specific scientific discipline has its beginning around the early 19th century. Some argued that the beginning of biochemistry may have been the discovery of the first enzyme, diastase, in 1833 by Anselme Payen, while others considered Eduard Buchner's first demonstration of a complex biochemical process alcoholic fermentation in cell-free extracts to be the birth of biochemistry. Some might also point to the influential work of Justus von Liebig from 1842, Animal chemistry, or, Organic chemistry in its applications to physiology and pathology, which presented a chemical theory of metabolism, or even earlier to the 18th century studies on fermentation and respiration by Antoine Lavoisier.
The College of Biological Sciences (CBS) is one of seven freshman-admitting colleges at the University of Minnesota. Established in 1869 as the College of Science, the College of Biological Science is now located across both the Minneapolis and the St. Paul campuses. The current interim dean is David Greenstein.
The following outline is provided as an overview of and topical guide to medicine:
Ewald Rudolf Weibel HonFRMS was a Swiss anatomist and physiologist and former director of the Institute of Anatomy at the University of Bern. He was one of the first scientists to describe the endothelial organelles Weibel–Palade bodies, which are named after him and his Romanian-American colleague George Emil Palade. He was known for his work on the anatomy of gas exchange in lungs on multiple spatial scales using stereology.
The following outline is provided as an overview of and topical guide to physiology:
Together with physiology and biochemistry, anatomy is one of the basic sciences that are to be taught in the medical curriculum.