Over the centuries, human beings have tried to find explanations for what is happening around us and have wanted to understand how our bodies work.

Understanding the functioning of living organs and why their different parts (cells, muscles, joints, etc.) have great applications. For example, a greater knowledge of cancer cells has been key to medicine and is necessary to improve our health. Likewise, knowing what the role of our muscles is can help us in sports performance or in recovery from injuries.

In response to this need for knowledge, physiology was born : it is a sub-discipline of biology that studies the functions and anatomy of living systems.

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History of Physiology

The word Physiology comes from the Greek φυσις, “physis”, which refers to the term “nature”, and λογος, “logos”, which means knowledge.

1. Ancient and Middle Ages

Its origins date back to the 5th century BC , at the time of Hippocrates, the father of medicine, who was born in Greece in 460 BC. He is known for his theory of humours and his great contributions to medical science. However, Aristotle’s critical thinking and his ideas of the relationship between structure and function, as well as Galen’s interest in experimentation, were also decisive in the development of this biological science.

The Middle Ages was also a crucial period in the development of Physiology with contributions from the Arabs, who integrated the Greek and Indian knowledge of those times. Some characters of the time were very important, such as Avicenna and Ibn al-Nafis, the latter known as the father of circulatory physiology (he correctly described the Anatomy of the Heart, the structure of the lungs and their circulation).

2. Modern and contemporary age

The Renaissance is known to be the era of physiological research in the Western world , as it was during this period that the modern study of this discipline was activated. The works of Andreas Vesalio are considered very influential and this author is usually referred to as the founder of human anatomy. Later, William Harvey, as a developer of experimental physiology, and Herman Boerhaave, as a founder of clinical teaching, allowed the progress of physiological knowledge and its diffusion in academic environments.

This knowledge continued to accumulate over the centuries, especially from the 19th century, when the American Physiological Association was founded and when the Cell Theory of Matthias Schleiden and Theodor Schwann appeared. Other authors such as Ivan Pavlov also made findings that were crucial for other disciplines such as Psychology or Education.

In the 20th century, Evolutionary Physiology became a different discipline. The technological advances of the last decades have allowed this science to increase its discoveries and its contributions to humanity.

Basics of Physiology

The structure and life of living beings is more complex than the sum of its separate parts (cells, tissues, organs, etc.). For this reason, Physiology is based on the foundations of other disciplines related to Biology:

  • Anatomy : Studies the bones, muscles, joints, etc.

  • Biophysics : It focuses on the study of physical principles that are present in the processes of living beings.

  • Genetics : It refers to the study of the hereditary phenomena that are transmitted from one generation to another.

  • Biochemistry : This science deals with the study of the chemical composition of living organisms.

  • Biomechanics : Studies the mechanical forces and structures that act and are present in living beings.

Types of Physiology

Given the number of fields that Physiology covers, it is possible to classify this discipline into different specialties:

1. Plant physiology

The study of those physiological components that affect plants and vegetation, such as photosynthesis, plant nutrition and reproduction or the functions of plant hormones.

2. Animal physiology

This is the branch of Physiology that deals with the biological study of animal species.

3. Human physiology

This branch of Physiology belongs to Animal Physiology, but focuses on the study of the human body and its various parts and functions.

4. General physiology

The study of both plant physiology and animal physiology is known as general physiology.

5. Comparative physiology

It aims at comparing the functioning and structures of animals and man.

6. Cellular physiology

Focused on studying the functions and anatomy of cells and how they capture stimuli and process information, reproduce and grow, feed themselves, etc.

7. Physiological Psychology

It deals with the study of the biological structures, elements and processes that are related to mental life and normal or pathological behaviour.

Other Physiology

The above classification is the most important, however, there are other types of Physiology according to different authors.

  • Embryonic physiology : as its name indicates, its study revolves around the comparison of different types of embryos of animals in general.

  • Physiology of hearing : It is necessary to study the Anatomy and Physiology of the hearing apparatus.

  • Cardiac physiology : It is in charge of the study of the anatomy and functioning of the heart.

  • Renal physiology : Studies the function and structure of the kidneys and especially of the nephron, the basic functional unit of this organ.

  • Physiology of tissues : It is related to Cellular Physiology as tissues are unions of cells that work together to perform a specific task

  • Physiology of vision : Studies the anatomy and functions of the eye.

  • Physiology of reproduction : It is in charge of studying the mechanisms related to the reproduction of living beings.

  • Vascular physiology : Studies the structures and functions that perform veins, arteries and capillaries.


Physiology can be classified into different types; however, they all refer to general physiology: a science closely linked to Biology that has allowed us to understand how our organism works, that of other animals , plants and microorganisms.

The discoveries in Physiology have been key to the development of other disciplines such as Medicine, Psychology or Sports Training.

Bibliographic references:

  • Marieb, E.N. Essentials of Human Physiology and Anatomy. 10th Edition, Benjamin Cummings, 2012.
  • Widmaier, E.P., Raff, H., Strang, K.T. Vander Human Physiology 11th Edition, McGraw-Cerro, 2009.
  • Withers, P.C. Comparative animal physiology. Saunders University Press, New York, 1992.