What Is Physiology?

Editor's Choice
Main Category: Biology / Biochemistry
Article Date: 09 Aug 2012 - 14:00 PDT


Physiology aims to understand the mechanisms of living - how living things work. Human physiology studies how our cells, muscles and organs work together, how they interact. Physiology, sometimes referred to as the "science of life", looks at living mechanisms, from the molecular basis of cell function to the whole integrated behavior of the entire body.

The word "physiology" comes from the Ancient Greek physis, which means "nature, origin", and logia, which means "study of".

Physiologists are forever attempting to find the answers to key questions in single cell functions, how human populations interact, our environment on earth; in other words, an extremely wide range of subjects.

Physiologists say that physiology is a fundamental science for understanding about "life", how to go about treating diseases and coping with the stresses our bodies are exposed to in different environments. Pathophysiology seeks to understand the abnormalities that occur in human and animal diseases. Physiologists work closely with other scientists and health care professionals in seeking out new methods for treating those diseases (translational research).

What is the difference between physiology and anatomy?

Anatomy examines and describes the structures of living things. Anatomy studies the form, while physiology looks at the function - anatomy looks at what it is, while physiology looks at what it does.

Physiology and anatomy are very closely related disciplines; they are intrinsically linked. Medical students tend to study the two disciplines in tandem.

According to Medilexicon's medical dictionary, Physiology is:

"The science concerned with the normal vital processes of animal and vegetable organisms, especially as to how things normally function in the living organism rather than to their anatomic structure, their biochemical composition, or how they are affected by drugs or disease."

The history of physiology

According to archeological and historical records, human physiology, as a kind of discipline, started around 420 BC in ancient Greece at the Hippocratic School of Medicine. Hippocrates of Kos (460-370 BC), considered by many as the "father of medicine" as we know it today, established medicine as its own discipline. Along with his students, he wrote extensively on physiology.

Some say that Aristotle (384 BC - 322 BC), who focused on the relationship between structure and function, was the real pioneer of physiology.

Galen (Claudius Galenus, circa 129-200/216), a prominent Greek physician in Ancient Rome, dissected animals and became by contemporary standards an expert anatomist and physiologist. He said that monkeys that walked on two legs, like we do, would most probably provide researchers with knowledge that could be applied to humans. Galen is known as the "founder of experimental physiology".

It was not really until the 19th century that physiology started making rapid advancements. Matthias Schleiden (1804-1881), a German botanist, and Theodor Schwann (1810-1882), a German physiologist, were co-founders of the cell theory - the idea that every living thing is made up of cells; with cells being the basic unit structure of everything that lives.

Claude Bernard (1813-1878), a French physiologist, made further discoveries which eventually led to his concept of milieu intérieur (the environment within), in which he refers to the extra-cellular fluid environment which protects tissues and organs of multicellular living organisms. The concept was later investigated further by Walter Cannon (1871-1945), an American physiologist, who named it "homeostasis".

1858 - Joseph Lister studied the cause of blood coagulation and inflammation that occurred after injuries and surgical wounds. Later on he discovered antiseptics, and found that they could dramatically reduce surgical mortality rates.

During the 1870s, Harvard University, USA, started a medical physiology program. Its first full -time faculty member was Henry Bowditch.

In 1891, Ivan Pavlov started researching conditional reflexes. He observed how dogs' saliva production would respond to various sounds and other stimuli. He was awarded the Nobel Prize for Medicine and Physiology in 1904. During the last century, scientists became increasingly interested in how non-human beings function. It was during the 20th century that the fields of comparative physiology and ecophysiology were born.

In 1901 John Jacob Abel and Jokichi Takamine isolated and purified adrenaline (epinephrine) from the adrenal gland. It was the first hormone ever to be identified and synthesized.

In 1911, a group of respiratory physiologists, led by J. S. Haldane, climbed to Pike's Peak to study what effect altitude might have on human breathing.

Insulin is isolated by Charles Best and Frederick Banting in dogs. Their work eventually turned diabetes from a deadly disease to a chronic one. They were awarded the Nobel Prize in 1923.

Andrew Huxley and Alan Hodgkin, in 1952, discovered the ionic mechanism in which nerve impulses are transmitted.

As a result of advances in the physiological studies of the heart, Christiaan Barnard, South Africa, performed the first successful human heart transplant in 1967.

During the 1960s, physiologists had observed that snakebite victims experienced serious falls in blood pressure and fainted. They eventually isolated the compound in the snake venom that blocked ACE (angiotensin converting enzyyme), an enzyme that controls blood pressure. From this research ACE inhibitors, drugs for controlling hypertension (high blood pressure), were developed and eventually approved by the US FDA.

The cystic fibrosis gene is discovered by Lap Chee Tsui, Jack Riordan and Francis Collins in 1989.

The mechanism that regulates cell groth, division and death was discovered by Paul Nurse, Leland Hartwell and Timothy Hunt in 2001.

How to become a physiologist

Becoming a physiologist may vary, depending on the country you live in. The example below applies to the USA:

• Study for a Bachelor's Degree - ideally, a degree in physiology. If your college does not offer physiology as a major, you should consider a biological science degree which includes physiology in its curriculum. Most of these courses last four years.


• Study for a Master's Degree - such as an M.S. (Master of Science) in Physiology, or an M.S. in Applied Anatomy and Physiology. Internships may help students become familiar with what kind of work is involved.


• Get some practical work experience - this may involve entry-level jobs or internship programs to build up work experience in the field. Most vocational employment opportunities involve working as laboratory assistants or research assistants.


• Complete a Doctorate Program - in order to get the good jobs, most employers ask for a doctoral degree in physiology. According to US authorities, biological science job opportunities will have grown by 20% by 2018 (compared to 2008).

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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