Physiology is the study of body functions, their mechanisms and regulations in all living organisms. Human physiology is the study of functions of various cells, organs and organ systems of human body. It encompasses the integration and control of organ systems that help in smooth functioning of body systems as a single unit. Medical physiology is the application of knowledge of human physiology in the management of dysfunctions and diseases in human beings.
In essence, human physiology is similar to the physiology of other mammals and vertebrates. However, as human being is the highest creation in the hierarchy of nature's evolution, the physiological processes that govern human life are more refined and developed. Nevertheless, the intricacies of human mind and vital and their profound influence on body functions have made human physiology more complex. Therefore, treatment of human diseases not only requires knowledge in physiology and medicine, but also the understanding of human behavior.
PHYSIOLOGY FOR LEARNING MEDICINE
Physiology, the Mother of Medicine
Physiology provides the essential knowledge to understand the process of homeostasis, which is defined as the constancy of the internal environment of the body. Homeostasis is the state of internal harmony among the body systems. A disease is an expression of functional disharmony of the systems that usually occurs due to prolonged disturbances of any kind. Understanding the nature of disturbance is critical to comprehend the pathophysiology of a disease and the physiological basis of management of the disease. Therefore, to learn any branch of medicine, it is essential to acquire the basic knowledge of systemic physiology related to the specialty. The concept in physiology helps understand, diagnose and treat the disease. For example, for management of a case of acute myocardial infarction (AMI), the physician should know the physiology of coronary blood flow, electrophysiology of cardiac myocytes, homeostasis of myocardial perfusion, principle of regulation of coronary circulation, and the factors that disturb coronary hemodynamics to produce myocardial ischemia. All these physiology concepts help the physician to understand the mechanism of genesis and spread of pain of AMI, to appreciate the nature of radiation of myocardial ischemic pain to left upper arm, to interpret ECG abnormalities to diagnose AMI, and to prescribe appropriate drugs that improve coronary blood flow, re-establish myocardial perfusion and prevent progression of infarction. For many diseases, knowledge in physiology facilitates proper diagnosis and effective treatment. Therefore, the great Physiologist EH Starling had said “Physiology of Today is the Medicine for Tomorrow”.
Scientist contributed
In this picture, Starling in the midst of an experiment upon circulation with a dog, in 1926.
Ernest Henry Starling was an English physiologist. His main collaborator was his brother-in-law, William Maddock Bayliss. His major contributions to physiology were: the Starling equation, describing fluid shifts in the body, the discovery of peristalsis (with Bayliss), the discovery of secretin, the first hormone (with Bayliss), the introduction of the concept of hormones and the discovery that the distal convoluted tubule of the kidney reabsorbs water and various electrolytes. Starling is most famous for developing the “Frank-Starling law of the heart”, presented in 1915 and modified in 1919. He died in 1927 at the age of 61.
A practitioner should have basic knowledge in physiology to become a good physician. Also, a physiologist by virtue of his knowledge and experience is inherently a good physician. Therefore, I always profess “A good physician is a physiologist, and a good physiologist is a physician”.
For Learning Medical Subjects
A medical student with ample knowledge in physiology can easily learn pharmacology and pathology. In principle, pharmacology is extension of physiology. For example, while learning pharmacotherapy for bronchial asthma, the student learns the use of catecholaminergic agents, especially β-receptor agonists that cause bronchodilation and provide immediate relief. It is easy for the student to understand pharmacotherapeutics of asthma as he has studied in physiology that sympathetic stimulation causes relaxation of bronchial smooth muscle by releasing norepinephrine, acting through β-receptors. Similarly, action of all of drugs has physiological basis; and therefore, a fundamental knowledge in physiology is essential for learning pharmacology.
Physiology is useful in learning pathology. For example, in physiology the student learns neutrophil as the first line of defence against acute infections and monocyte as the defence for chronic infections. Therefore, in histology slide when he finds abundant neutrophils in the microscopic field, he comprehends the infection or inflammation is of acute nature, and presence of abundant monocytes or macrophages makes him realize the infection or inflammation is of chronic nature. Similarly, understanding pathological basis of diseases requires the basic knowledge in physiology. In fact, all the diseases have a pathophysiological basis.
Likewise, the student utilizes his knowledge in physiology for learning all branches of medicine. Etiopathogenesis, clinical manifestation, diagnosis and management of all diseases have the physiological basis. Without basic concepts in physiology, a student will not be able to understand the principle of medicine. Hence, all the chapters in medicine textbooks start with an introduction to relevant clinical physiology.
In surgery textbooks, there are portions for surgical physiology. In all branches of medicine, such as gynecology, ophthalmology, otorhinolaryngology, pediatric medicine, endocrinology, oncology, gastroenterology, pulmonology, neurology, cardiology and so on, a considerable portion is devoted to clinical physiology of the topic that helps reader comprehend the physiological basis of the management.
PHYSIOLOGY FOR MEDICAL PRACTICE
For Becoming a Good Physician
The knowledge in physiology guides a physician to understand the principles of medical practice and the rationality of disease management. The present-day physician often tends to provide prompt symptomatic relief by prescribing a list of medicines starting from analgesics to antibiotics. This is because the modern man is in a hurry and wants immediate relief from the sufferings. There is no time, interest and knowledge for an assisted-natural remission of the disease. The physician wants to earn his money and reputation of being a good physician by providing a quick relief. But, this type of treatment does not help the person in the long run, as often medicine suppresses immunity. Although, few diseases require prompt and aggressive treatment by modern therapeutics such as antibiotics, many diseases are cured by assisted-natural remission with minimum medicines. For example, for management of hypertension in the early stage, a good physician can advise reduction in salt intake and stress level, practice of mental relaxation, regular physical exercises and adaptation to a healthy diet and life style. Usually, these nonpharmacological practices are known to decrease blood pressure. Therefore, the physician should motivate his patient to practice natural measures, and should not prescribe a list of blood pressure reducing drugs that have known side effects. Medicines should be prescribed only when these natural means fail to show desirable results.
Physiology educates physicians that effective treatment of many diseases requires improvement of immunity of the subject as enhancement of immunity halts the spread of diseases and slowly discards the disease from the body. For, example, fever due to acute inflammation is a natural manifestation of the disease and part of the defense mechanisms of the body. Therefore, instead of immediately prescribing antibiotics, physician can reassure the patient that the body heals itself or at best he can prescribe mild antipyretic-analgesic. Administration of higher antibiotics and analgesics suppresses the immunity of the patient that exposes him to various infections. The doctor should explain to the patient that fever is a natural defence mechanism against infection, as rise in body 5temperature kills the organisms. Moreover, prescribing antibiotics in the early part, the course and usual manifestation of the disease is missed, and therefore the diagnosis of the disease is overlooked. Another example, a simple boil (cellulitis), which heals by itself, does not warrant prescription of antibiotics. A doctor should assure the patient about the natural course of the boil and may advise him for warm fomentation on the part that improves blood flow to the region and facilitates the process of healing. Treatment by antibiotic from the beginning may halt the healing process of the boil and in some cases may produce antibioma (tumor due to antibiotics). A doctor should know that frequent use of antibiotics suppresses immune system of the body and predisposes the body to other infections. A physician with ample knowledge in physiology helps patient in facilitating the natural remission and recovery without prescribing higher medicines. Hence, a good physician is a physiologist.
For Disease Prevention and Health Promotion
Pathophysiology elucidates the physiological basis of pathology. A physician with physiology knowledge understands the measures that prevent occurrence of diseases. Presently, India is the epicenter of metabolic disorders and cardiovascular risks. A physiologist knows that regular physical exercises with a good eating habit retard the process of atherosclerosis and oxidative stress that prevents occurrence of cardiovascular and cerebrovascular accidents, many metabolic diseases, and retards degeneration and decay. A physiologist not only practices healthy lifestyle himself for his personal health but also encourages others to adapt to such a life. This promotes the community health. Therefore, a good physiologist is a physician.
We give emphasis on preventive and promotive aspects of health, which will be more promulgated by physiologists and will be established as preventive and promotive physiology.
PHYSIOLOGY FOR MEDICAL RESEARCH
Physiology is the core subject of medical research. The inventions and discoveries in medical science and advances in medicine are mainly due to research contributions from physiology. Therefore, from its inception in 1901, the Nobel Prize in the field of medical sciences has been designated as ‘Nobel Prize in Physiology’ or ‘Physiology and Medicine’. Many Nobel Prize winners in medicine starting from Emil Adolph Von Behring (1901), Sir Ronal Ross (1902), Prof. Finsen NR (1903), Prof. Ivan Petrovich Pavlov (1904) to Dr. Robert G. Edward (2010), John O'Keefe (2014) are physiologists or physicians who have worked in medical physiology or medical fields linked to physiology. Etiopathogenesis of the diseases and physiological basis of management are elucidated through research discoveries in physiology.
Scientist contributed
Prof. Behring was awarded first Nobel Prize in Physiology or Medicine, 1901, for his work on physiology of immunity and serum therapy, especially its application against diphtheria. This opened the path in the domain of medical therapy, a victorious weapon against illness and deaths. He developed quantitative methods for the bioassay of antisera and antitoxins.
Scientist contributed
The Nobel Prize in Physiology or Medicine for the year 2010, was awarded to Robert G. Edwards for the development of in vitro fertilization; Dr. Edward had worked extensively in the field of reproductive physiology and infertility for more than 4 decades.
Scientist contributed
The Nobel Prize in Physiology or Medicine 2014 was divided, one half awarded to John O'Keefe, the other half jointly to May-Britt Moser and Edvard I. Moser “for their discoveries in Neurophysiology that constitute a positioning system in the brain. They studied the movements of rats and signals from nerve cells in the hippocampus, an area located in the center of the brain. In 1971 he discovered that when a rat was at a certain location in a room, certain cells were activated, and that when the rat moved to another location, other cells became activated. That is to say, the cells form a kind of internal map of the room.
For Basic and Clinical Research
Research in basic and clinical physiology has contributed to enormous growth of clinical medicine. Basic research reveals the mechanism and pathophysiology of diseases, whereas clinical research unravels the management and prevention of diseases. Usually clinicians will not have enough interest and time for research. The collaborative research between physiology and clinical departments creates avenues for clinical research, ignites research interest in clinicians, improves research outlook, attracts extramural financial support from various funding agencies and yields more productive results. The ultimate objective of a medical research should be to reduce suffering, facilitate healing, cure the ailment, prevent the occurrence of disease and promote health. Physiologists 6should make efforts for larger participation of physician in research and ensure research to be more applied and clinical.
PHYSIOLOGY FOR INTEGRAL PROGRESS
Physiology for Ethics
Physiology teaches the ethics and values of life. Appropriate judgment and application of knowledge for healing the human suffering is true physiology. Ethics of medical practice was devised by Hippocrates, an ancient Greek physician. Hippocrates was a teacher at the School in the Health Temple at Cos, Greece. Writings of the group are distinguished by a high ethical tone, keen observation, logical application of existing ideas and cautious judgment. Hippocrates established the popular ethics of medical practice for physicians, which is commonly known as ‘Hippocratic Oath’ that all physicians solemnly pledge at the time of obtaining their degrees to start medical practice [Reference: Jones WHS and Withington ET. The works of Hippocrates. 4 volumes. London, Heinemann: 1923].
Scientist contributed
‘Hippocratic Oath’ with modification is as follows…‥
I solemnly pledge to consecrate my life to the service of humanity; I will give to my teachers the respect and gratitude that is their due;
I will practice my profession with conscience and dignity;
The health of my patient will be my first consideration;
I will respect the secrets that are confided in me, even after the patient has died;
I will maintain by all the means in my power, the honor and the noble traditions of the medical profession;
My colleagues will be my sisters and brothers;
I will not permit considerations of age, disease or disability, creed, ethnic origin, gender, nationality, political affiliation, race, sexual orientation, social standing or any other factor to intervene between my duty and my patient;
I will maintain the utmost respect for human life;
I will not use my medical knowledge to violate human rights and civil liberties, even under threat;
I make these promises solemnly, freely and upon my honor.
Physiology for Integral Knowledge
Physiology provides the knowledge to gain and maintain good health. Physiology teaches us how various organsystems in the body work inter-dependently for maintaining an effective homeostasis. For example, respiratory system provides oxygen to the tissues of the body with the help of a central pump (the heart) that maintains a dynamic circulation, under the integrated control of neural and endocrine factors. In this process, no organ-system is big or small, as contribution of each organ leads to fulfillment of the primary objective of supplying blood, oxygen and nutrients to the body parts. Derangement of any of these participating systems leads to development of bodily dysfunctions. We should understand that this basic principle of a structured system of working is essential for creating a healthy environment and harmonious progress of an organization.
Physiology for Spiritual Progress
The fundamental aim of our terrestrial existence is to attain perfection; the perfection in physical growth, perfection in beauty, perfection in mind and intellect and perfection in inner disciplines. A progressive evolution of consciousness is spirituality. Inner progress is achieved by improvement in body physiology. For example, practice of pranayama not only improves breathing capacity and oxygenation of the body, but also strengthens the neural elements, metabolic functions and causes purification of mind and vital and enhances cognitive faculties. In human body, there are subtle physical centers such as spinal-cord center, heart center, throat center, pineal center, etc. and they are rich in different kinds of spiritual energies. Focusing the concentration on these centers releases the energy from the center that helps in purifying and enriching the mind and body. With knowledge in physiology it becomes easy concentrating and releasing energy from these centers. A physiologist having the holistic knowledge of working of the body and with true aspiration for progress is privileged for acquiring higher knowledge, force and consciousness. One will realize that learning and teaching physiology in its true essence is the best method to acquire peace of mind, release stress from the body, and establish contact with the higher consciousness, i.e., with the Divine.
Thus, to study human physiology is an opportunity, to become a physiologist is a privilege, to encourage others to practice physiological means of health-promotion is a unique occasion, and to practice physiology for integral progress is the reality in life.