Physiology Lpr
Cherie Trojak
Physiology is the study of how the human body works. It describes the chemistry and physics behind basic body functions, from how molecules behave in cells to how systems of organs work together. It helps understand what happens when your body is healthy and what goes wrong when you get sick.
Most of physiology depends on basic research studies carried out in a laboratory. Some physiologists study single proteins or cells, while others might do research on how cells interact to form tissues, organs, and systems within the body.
For instance, you may itch after a mosquito bites you because it has histamine in its saliva. Histamine binds to receptors on nerve endings in your skin. These nerve endings send signals to the brain that the bite itches.
Or you may have heart failure because of high blood pressure that isn't controlled. When you have high blood pressure, your heart has to work harder than normal to pump blood throughout your body. When your heart is strained over time, it can weaken and fail.
Human physiology is focused on how the systems in your body operate, including your circulatory system, immune system, nervous system, and respiratory system. By understanding how each one works when healthy and when sick, scientists can understand how to treat illness.
Animal physiology is the study of how organ systems and tissues work in the bodies of animals. This includes how they process nutrients, regulate their body temperature, and respond to their environment.
For each system, physiology sheds light on the chemistry and physics of the structures involved. For example, physiologists may study the electrical activity of cells in the heart that control its beat. Or they may explore how eyes detect light, from the way the cells in the retina process light particles called photons to how the eyes send signals about images to the brain.
Physiology revolves around understanding how the human body maintains a steady state while adapting to outside conditions, a process called homeostasis. It looks at ways your organ systems keep your temperature stable in different environments. And how your body keeps your blood sugar and other chemical levels constant even when you eat different foods. These are the kinds of questions physiologists aim to answer.
By shedding light on normal body functions, physiology can teach lessons about what goes wrong in disease. For instance, physiologists have figured out how different types of cells in the pancreas release hormones to control blood sugar levels. That helps doctors understand and treat diabetes.
Anatomy is visible, and ancient doctors and scientists studied it through dissections, surgeries, and observation. But how the body actually works is harder to explore, making physiology a more modern science.
Early explanations of how the human body worked were often guesses based on processes that were familiar to scientists. For example, some thought the formation of an embryo was similar to how milk turns into cheese. Other early scientists compared blood flow throughout the body to weather patterns.
In the 17th century, microscopes helped shed new light on the cells that make up the human body, leading to a new understanding of physiology. More recently, tools like gene sequencing technologies and new types of body scans have given physiologists an expanded vision of the human body.
Physiology (/ˌfɪziˈɒlədʒi/; from Ancient Greek φύσις (phsis) 'nature, origin', and -λογία (-loga) 'study of')[1] is the scientific study of functions and mechanisms in a living system.[2][3] As a subdiscipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out chemical and physical functions in a living system.[4] According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology.[4]
Central to physiological functioning are biophysical and biochemical processes, homeostatic control mechanisms, and communication between cells.[5] Physiological state is the condition of normal function. In contrast, pathological state refers to abnormal conditions, including human diseases.
Because physiology focuses on the functions and mechanisms of living organisms at all levels, from the molecular and cellular level to the level of whole organisms and populations, its foundations span a range of key disciplines:
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.[7]
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,[4] 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.[8]
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.[9] Change in behavior as a result of these substances is often used to assess the health of individuals.[10][11]
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.[12]
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).[23]
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.[24]
The Physiological Society was founded in London in 1876 as a dining club.[25] 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."[26]
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,[23] later renamed in the 20th century as cell biology.[31]
In the 20th century, biologists became interested in how organisms other than human beings function, eventually spawning the fields of comparative physiology and ecophysiology.[32] Major figures in these fields include Knut Schmidt-Nielsen and George Bartholomew. Most recently, evolutionary physiology has become a distinct subdiscipline.[33]
Recently, there have been intense debates about the vitality of physiology as a discipline (Is it dead or alive?).[34][35] If physiology is perhaps less visible nowadays than during the golden age of the 19th century,[36] 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.[37] Furthermore, physiology is still often seen as an integrative discipline, which can put together into a coherent framework data coming from various different domains.[35][38][39]
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.[40] In 1902, the American Physiological Society elected Ida Hyde as the first female member of the society.[41] Hyde, a representative of the American Association of University Women and a global advocate for gender equality in education,[42] attempted to promote gender equality in every aspect of science and medicine.
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