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History of Homeostasis

Context for the Big Ideas in Anatomy and Physiology 12

Alcmaeon of Croton

500 B.C.

Greek Philosopher & Physician (fl. 500 BC)

Proposed what can be called a “balance of opposites” to explain health and disease.

“Health is the equality of rights of the functions, wet-dry, cold-hot, bitter-sweet and the rest; but single rule of either pair is deleterious.”

Hippocrates of Kos

460-377 B.C

Greek Physician (460-377 B.C.)

"Father of Medicine"

Proposed that health was the product of the balance and mixture of four body fluids or humors: blood, phlegm, yellow bile, and black bile.

“Health is primarily that state in which these constituent substances are in correct proportion to each other, both in strength and quantity and are well mixed. Pain occurs when one of these substances presents either a deficiency or excess, or is separated in the body and not mixed with the others.”

Recognized the role of nature’s helping hand in the healing process and the ability of the body to heal itself. It was the role of the physician to clear the path so that nature could take its course.

Jean Francois Fernel

French physician (1497–1558)

First introduced the term “Physiology” as the study of the function of the healthy body as distinguished from pathology, the study of disease

“Anatomy is to physiology as geography is to history; it describes the theatre of events.”

1497-1558

William Harvey

English Physician (1578–1657)

First to use carefully designed human and animal experiments to establish the function of a major bodily organ system with his description of the circulation of the blood

“It has been shown by reason and experiment that blood by the beat of the ventricles flows through the lungs and is pumped to the whole body … the blood in the animal body moves around in a circle continuously, and … the action or function of the heart is to accomplish this pumping. This is the only reason for the motion and beat of the heart.”

1578–1657

Claude Bernard

French physiologist (1813–1878)

Founder of modern experimental physiology.

He developed the concept of “a fixité du milieu intérieur,” that is, organisms maintain a stable internal environment despite changing external conditions.

He recognized that the body possesses mechanisms that operate in a coordinated fashion to maintain a relatively constant temperature and blood glucose concentration and this internal stability was vital for the health of the organism

“La fixité du milieu intérieur est la condition de la vie libre, independante”

[The fixity (i.e., constancy or stability) of the internal environment

is the condition for the free, independent life]

1813–1878

Charles R. Richet

French physiologist (1850-1935)

Student of Bernard who later won the Nobel Prize in Physiology and Medicine, stressed the dynamic stability of the internal environment

“The living system is stable…it must be in order not to be destroyed, dissolved or disintegrated by colossal forces, often adverse, which surround it. By an apparent contradiction, it maintains its stability only if it is excitable and capable of modifying itself according to external stimuli and adjusting its response to the stimulation. In a sense, it is stable because it is modifiable – the slight instability is the necessary condition for the true stability of the organism.”

1850–1935

Walter Cannon

1871–1945

American physiologist (1871-1945)

Built upon the work of Claude Bernard and coined the word homeostasis to describe a self-regulating process by which biological systems maintain stability while adjusting to changing conditions.

“The coordinated physiological processes which maintain most of the steady states in the organisms are so complex and peculiar to living beings – involving, as they may, the brain and nerves, the heart, lung, kidneys and spleen, all working cooperatively – that I have suggested a special designation for these states, homeostasis. The word does not imply, something set and immobile, a stagnation. It means a condition – a condition which may vary, but is relatively constant.”

Cannon, 1939

Homeostasis

From the Greek words:

Ǒμoιoς (hómoios) “similar”

στάσις (stásis) “standing still”

(together to mean staying similar and not staying the same)

Homeostasis

J. Scott Turner

1951- Present

American physiologist (1951-)

Described homeostasis as a dynamic disequilibrium

Dynamic, as a stable internal environment requires continuous monitoring and adjustments in order to maintain a balance between opposing forces (what he calls disequilibrium)

“properly understood, homeostasis is life’s fundamental property, what distinguishes it from non-life. In short, homeostasis is life.” Turner, 2017

Control Theory

1960s

Application of control theory from systems engineering to explain self-regulation in biological systems.

The “constancy” of internal conditions is maintained by the complex interaction of multiple negative (and positive) feedback systems.

The interaction of these regulatory mechanisms not only increases the stability of the system but provides redundancy (back-up) such that failure of one component does not necessarily lead to catastrophe. Thus, from its inception physiological investigations have been directed toward understanding the organism as a single functional entity.

Core Concept in Biology

Present

2007

Group of 21 biologists from a wide range of disciplines agreed that “homeostasis” was one of eight core concepts in biology.

2009

The American Association of Medical Colleges and Howard Hughes Medical Institute in its report on the scientific foundations for future physicians similarly identified the ability to apply knowledge about “homeostasis” as one of the core competencies.

2018 BC Curriculum: Anatomy & Physiology 12 'Big Idea'

Homeostasis is maintained through physiological processes.

Curricular Content Related to Homeostasis

Homeostasis in the BC Curriculum

Students are expected to know the following:

  • Feedback loops and regulation of the body's internal environment.

  • Organ systems role in maintenance of homeostasis.

  • Disease as an imbalance in homeostasis.

  • Holistic approach to health

Indigenous Perspectives

Alternative Teachings

The Medicine Wheel is a holistic system used to create balance and wellness in people.

With the same principles as homeostasis. Indigenous perspectives of wellness also

consider non-physical elements of wellness at all stages of life.

The principle of interconnectedness can be related to the mechanisms of feedback and regulation in the body as well as in ecosystems.

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