Many college programs focused on biology or human health require physiology courses. But what is physiology? Physiology is the study of functions within the body. It is largely focused on "how" questions, such as:
Physiology is a broad field that produces important findings for human health. It would be incredibly difficult to understand all aspects of the body's physiology. Because of this, it's broken into smaller, more specific fields. For instance, respiratory physiology is interested in the functions involved in breathing, while cardiac physiology is interested in the functions pertinent to the heart and circulatory system. This lesson investigates physiology in more detail to understand how it differs from similar fields, and how it is applied to systems and education.
A common topic in biological curriculum is often called "A and P," or "Anatomy and Physiology." While these terms are often seen together, they are not the same. Anatomy is the study of how parts of the body are shaped. For instance, it may be concerned with the shape of a joint or anomalies in the curvature of the skull. Anatomy is part of a larger field of study called morphology, which is interested in the shape and structure of bones and organs (their anatomy) as well as variations in numbers and organization of those structures.
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Form gives rise to function. This means that the shape of a structure often coincides with its use. For instance, human hands are shaped for grasping and holding. Cat paws, while containing homologous (like) structures, are better suited for jumping, climbing, and tearing. Because the relationship between shape and function is so important, anatomy and physiology are often taught in conjunction with one another. The physiology definition may be concerned with how a joint moves, but the anatomy of a joint allows it to do so.
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Try it nowPhysiology as a science can be traced back to ancient civilizations. In fact, evidence of physiological practices exists from ancient Egyptian societies and the Greek philosopher Hippocrates studied human systems prior to 400 BC. Despite its early origins, the term "physiology" wasn't officially coined until the early 1500's. Jean Fernal was the first to describe physiology as a proper field during his work on the human spinal canal.
Since it's description, famous physiologists have contributed key ideas to the field that act as central themes. In 1865, Claude Bernard introduced the idea of homeostasis. Homeostasis is the concept that life attempts to keep the internal environment (referred to as "milieu intérieur" by Bernard) as consistent as possible.
What is the study of physiology in ancient times compared to today? Modern physiology has expanded to answer more specific questions in ethical ways. Early investigations attempted on people were often viewed as unethical and dangerous. Because of this, physiology often implements model systems. Model systems are those that represent an aspect of human health for examination or experimentation without the need to potentially harm living individuals. Common models include mice, cadavers, and even (in today's world) computational models. These methods are also useful because they can be used to examine specific parts of physiology without having to consider the entire patient. For instance, a model can simulate a specific process in the lungs regardless of a potential issue in the kidneys that may somehow skew results. While animal model systems may offer important implications for human health, scientists must consider the differences between a specific animal's physiology and human physiology before making broad comparisons.
Physiological functions occur when specific organs and their subsequent systems engage in specific actions. Physiological functions include a structure and a process. Structures may include single organs, whole organ systems, or even specific tissues. Processes can include breaking down substances, creating substances, or transporting them. Thus, they depend on form and function. Below, investigate how different physiological systems engage in different functions.
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There are numerous physiological systems within the body, and they can be broken down into even smaller, more specific pathways when observing a specific process or action. Some of the most common physiologically defined systems in the body (and their descriptions) are highlighted in the table below.
| Phsyiological System | Description |
|---|---|
| Digestive System | How the body takes in, digests, and absorbs nutrients |
| Circulatory System | How blood flows throughout the body, how the heart functions |
| Immune System | How the body fights and prevents infections |
| Endocrine System | How hormones are released and distributed throughout the body |
| Integumentary System | How the skin functions and the roles it provides |
| Musculoskeletal System | How skeletal muscles and bones work together to provide movement |
| Nervous System | How neurons pass signals throughout the body to detect stimuli and elicit responses |
| Renal System | How the kidneys function to create urine and remove waste from the blood |
| Reproductive System | How male and female gametes join to create new life |
| Respiratory System | How the body takes in fresh oxygen and expels waste carbon dioxide |
There are multiple fields that are interested in utilizing physiology. Human physiology is interested in understanding systems within the human body to answer questions and provide efficient health care. Animal physiology may be interested in providing similar functions in animals, as well as utilizing animals as model systems to better understand aspects of human health.
Physiology can also be applied in many different ways. Cell physiology is interested in understanding the functions that occur within and between cells. Because of this, it is often interested in physiology on a microscopic and even molecular level. Systems physiology is interested in how systems function, such as those provided in the previous table. Evolutionary physiology is interested in how systems and their functions have changed throughout evolution. For instance, different animals possess hearts with a different number of chambers. How this change effects physiological processes and efficiency is often a topic of interest for evolutionary physiologists.
Defense physiology is interested in physiology involved in defense, such as fight or flight responses. It is often interested in how the body responses to stressful or threatening situations. Exercise physiology is an increasingly popular field of study that aims to investigate the processes involving movement of the body and its relation to energy expenditure.
Physiology is a broad field that is not exclusive to humans. In fact, it can be applied to a variety of organisms including animals, plants, and even microorganisms like bacteria. Physiological examples and questions are found wherever life exists.
Physiology is the study of function that is applied to living systems. It often coincides with anatomy, which is the study of how structures within living systems are shaped. Anatomy is part of a larger field of study known as morphology, which is interested in both the shapes and orientations of body structures. Because form and function are related, these fields are often studied together. They may be studied broadly (by looking at an entire organism) or on a finer scale (such as looking at individual cells, which are the basic units that compose living things).
Physiology has been practiced for thousands of years and was first coined by Jean Fernal in the early 1500's. However, the studies involved in physiology have existed long before its definition and ancient Greek physiology shaped studies that entered into Europe's renaissance. Since it's definition, key terms such as homeostasis (the ability of the internal environment, or "milieu intérieur" to remain constant) have been founded by prominent scientists such as Claude Bernard. Modern physiology often uses model systems instead of human subjects to examine specific systems, reduce the need to experiment on humans, and to simulate human physiology. Physiology is practiced in many fields and systems. It can also be applied to humans, plants, animals, and even microorganisms. Common fields include:
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This activity will help you assess your knowledge of the definition and history of physiology.
For this activity, you'll need a printer to reproduce the following page. Search for and circle or highlight the words that will complete each of the given clues. Afterwards, neatly write them in the appropriate blank spaces in the clues.
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Physiology is the study of the function of living systems. It aims to answer questions surrounding how processes within living organisms work.
There are many types of physiology. Physiology can be broken into systems (such as renal physiology or respiratory physiology) or into fields of study (such as cell physiology or defense physiology).
An example of physiology is exercise physiology. Exercise physiology is interested in investigating how movement of the body correlates with muscle growth and energy expenditure.
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