Introduction to physiology

1. COURSE: INTRODUCTION TO PHYSIOLOGY
Dr. (Mrs.) A. A Bayo-Olugbami

2. Suggested textbooks and resources …..
Medical Physiology (Guyton and Hall) Review of Medical Physiology, 23th Ed. (W.F. Ganong)
Vander’s Human Physiology, 11th Ed. (Widmaier, Raff,
Strang)

3. DEFINITIONS
 Physics + Biology = Physiology
 The branch of science dealing with the basic functions of living organisms.
 Science of “function”
 Physiological: “Normal”; not pathological. It means properties belonging to
normal functions of tissues, organs or body...
 It is the scientific study of body functions and mechanisms
 Physiology is the science of life. It is the branch of biology that aims to
understand the mechanisms of living things, from the basis of cell function at
the ionic and molecular level to the integrated behaviour of the whole body
and the influence of the external environment.
 Physiology is an experimental scientific discipline and is of central importance
in medicine and related health sciences. It provides a thorough understanding
of normal body function, enabling more effective treatment of abnormal or
disease states.

4. • Physiology is the study of animal (including human) function and can
be investigated at the level of cells, tissues, organ systems and the
whole body. The underlying goal is to explain the fundamental
mechanisms that operate in a living organism and how they interact.
WHY PHYSIOLOGY?
• Research in physiology helps us to understand how the body works in health and how it
responds and adapts to the challenges of everyday life;
• it also helps us to determine what goes wrong in disease, facilitating the development of
new treatments and guidelines for maintaining human and animal health.
• The emphasis on integrating molecular, cellular, systems and whole body function is what
distinguishes physiology from the other life sciences.
•

5. What do physiologists do?
All over the world, physiologists are working in universities, in research institutions,
in biotechnology companies and in the pharmaceutical industry to advance our
understanding of how the body functions.
• Physiology is an exciting and dynamic discipline that underpins translational and
clinical medicine. It also provides the interface between the physical sciences and
the life sciences.
• Physiologists study every aspect of the way human and other animal bodies
work. Some physiologists investigate the behavior of individual proteins in single
cells. Others are researching the interaction of cells in tissues, organs and systems
or study the integration of these systems to control the whole complex organism.
• They provide the foundation for many biological and clinical sciences, including
medicine and veterinary science.
• They work alongside elite athletes, helping to improve their performance and avoid
injury, or they investigate how the body adapts to extreme environmental
challenges, such as deep sea diving or prolonged space flight. Physiology is
recognized globally.

6. • Physiologists can travel the world to conferences and meetings to present their findings
to other scientists. Some physiologists report scientific developments for newspapers,
journals and other media, or play an advisory role to Government or charitable
organizations.
• Physiologists also use their skills in the legal arena, engaging in complex issues of patent
law, or in education, inspiring and nurturing the next generation. Studying physiology
opens doors to employment in all these areas and more.
• Physiology involves many vital concepts, and homeostasis is one of them. It is the process
through which a nearly stable internal environment is maintained in the body so that
cellular functions can proceed at maximum efficiency.
• Every body structure contributes in maintaining the internal environment within a normal
range. Changes in the normal range in the body due to infection, or disease lead to
symptoms and outward clinical signs.
• Alterations in homeostasis can be effect of a disease.
Understanding the control of homeostasis is very vital to pinpoint the root cause of any
disease.
• Not all physiologists are found in research laboratories, though. Physiologists also work
with patients in hospital clinics, helping with the diagnosis and management of disease.

7. HISTORY OF PHYSIOLOGY
• The study of physiology traces its roots back to ancient India and Egypt.
• As a medical discipline, it goes back at least as far as the time of Hippocrates, the
famous “father of medicine” – around 420 BC.
• Hippocrates coined the theory of the four humors, stating that the body contains
four distinct bodily fluids: black bile, phlegm, blood, and yellow bile. Any
disturbance in their ratios, as the theory goes, causes ill health.
• Claudius Galenus (c.130-200 AD), also known as Galen, modified Hippocrates’
theory and was the first to use experimentation to derive information about the
systems of the body. He is widely referred to as the founder of experimental
physiology.
• It was Jean Fernel (1497-1558), a French physician, who first introduced the term
“physiology,” from Ancient Greek, meaning “study of nature, origins.”
• Another leap forward in physiological knowledge came with the publication of
William Harvey’s book titled An Anatomical Dissertation Upon the Movement of
the Heart and Blood in Animals in 1628.

8. HISTORY CONT…
• Harvey was the first to describe systemic circulation and blood’s journey through
the brain and body, propelled by the heart.
• From here on in, the field of physiology opened up, and progress was made
quickly:
• Joseph Lister, 1858: initially studied coagulation and inflammation following
injury, he went on to discover and utilize lifesaving antiseptics.
• Ivan Pavlov, 1891 – conditioned physiological responses in dogs.
• August Krogh, 1910 – won the Nobel Prize for discovering how blood flow is
regulated in capillaries.
• Andrew Huxley and Alan Hodgkin, 1952 – discovered the ionic mechanism by
which nerve impulses are transmitted.
• Andrew Huxley and Hugh Huxley, 1954 – made advances in the study of muscles
with the discovery of sliding filaments in skeletal muscle.

9. Structural and functional hierarchy
Physiological terms;
• Function:
• Things to do...
• Mechanism:
• How to do...
Organization of life:
• Cell is the basic unit of life.
Hierarchical organization of life:
• Cells, tissues, organs, organ, systems
and organism

10. Organization of the Body
Structural Hierarchy
• Atoms: oxygen, carbon, hydrogen
• Molecules: water, sugar, peptides
• Macromolecules: proteins, polysaccharides
• Organelles: compartments within cell that cannot survive in isolation
• Cells: structural and functional unit of organisms
• Tissues: organization of cells with a common function
• Organs: structures composed of at least 2 tissues
• Organ Systems: organs operating to accomplish a common function

12. Organ-system
• Cardiovascular
System
• Respiratory System
• Digestive System
• Urinary System
• Reproductive System
• Musculoskeletal
System
• Nervous System
• Endocrine System
• Immune System