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Entropy vs. Atrophy: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Updated on November 8, 2023
Entropy is disorder increase in a system; atrophy is the decline or wasting in cells, tissues, or organs.

Key Differences

Entropy is a concept from thermodynamics relating to the measure of disorder or randomness in a system. It predicts the direction of processes and the energy distribution in a system at equilibrium. Atrophy, in contrast, is a biological term referring to the reduction in size or wasting away of an organ or tissue due to disease, lack of use, or hormonal changes.
Atrophy can be seen as the body's response to a decrease in demand or adverse conditions, leading to a reduction in the mass of muscles or organs. Entropy does not pertain to biology specifically, but rather to the tendency of systems to move towards disorder and can apply to physical, chemical, and informational systems.
Entropy increases over time in an isolated system, as energy is dispersed and systems become more disordered. Atrophy can also progress over time if the underlying cause persists, such as continued inactivity or ongoing nerve damage, leading to the gradual decline of the affected tissues' functionality.
In information theory, entropy measures the unpredictability or information content. Atrophy, while it does not have a direct equivalent in information theory, could metaphorically relate to the 'decay' or loss of information or function within a biological context.
While entropy is a fundamental concept affecting all physical processes, guiding our understanding of the universe's direction, atrophy is specifically focused on biological decline, highlighting the effects of certain conditions on living organisms.

Comparison Chart




Increases disorder
Decreases size/function

System Impact

Affects closed systems universally
Affects specific tissues/organs


Not reversible in isolated systems
Can be reversible if cause is addressed

Associated Law

Second law of thermodynamics
Pathophysiological processes


Can be quantified by change in heat divided by temperature
Measured by changes in size/volume

Relation to Time

Always increases over time in an isolated system
May progress if cause persists

Entropy and Atrophy Definitions


A decline into disorder or randomness.
The abandoned city fell into entropy.


Loss of muscle mass due to inactivity.
Prolonged bed rest can lead to atrophy of muscles.


The second law of thermodynamics.
In any energy exchange, entropy will increase.


The wasting away of body tissue.
After months in a cast, his leg muscles experienced atrophy.


A measure of disorder in a system.
The entropy of the room increased as the children scattered their toys.


A decrease in size or wasting of an organ.
The unused limb succumbed to atrophy.


In information theory, the uncertainty in a signal.
With high entropy, the message was nearly indecipherable.


A decline in effectiveness or vigor.
His intellect suffered atrophy from lack of practice.


A process of degradation or running down.
The machine's entropy was evident in its diminishing efficiency.


Diminution in the functionality of a biological system.
Without stimulation, brain cells may undergo atrophy.


Symbol S For a closed thermodynamic system, a quantitative measure of the amount of thermal energy not available to do work.


A wasting or decrease in size of a body organ, tissue, or part owing to disease, injury, or lack of use
Muscular atrophy of a person affected with paralysis.


A measure of the disorder or randomness in a closed system.


What is entropy?

Entropy is a measure of disorder or randomness in a system.

Can entropy be reversed?

In isolated systems, entropy cannot be reversed according to the second law of thermodynamics.

What does atrophy mean?

Atrophy refers to the reduction in size or the wasting away of an organ or tissue.

How is entropy related to temperature?

Entropy is related to temperature as changes in entropy can be measured by the amount of heat exchanged divided by the temperature.

Is atrophy reversible?

Atrophy can be reversible if the underlying cause, such as inactivity or nutrient deficiency, is addressed.

Is atrophy always a result of disease?

No, atrophy can also result from disuse, aging, or malnutrition, not just disease.

Is atrophy limited to muscles?

No, atrophy can affect any organ or tissue in the body.

Does entropy only apply to physical systems?

No, entropy also applies to informational and probabilistic systems.

Can exercise reverse muscle atrophy?

Yes, exercise can often reverse muscle atrophy by stimulating muscle growth and strength.

What causes atrophy?

Atrophy can be caused by inadequate nutrition, lack of physical activity, disease, or aging.

How is atrophy diagnosed?

Atrophy is diagnosed through physical examination, imaging tests, and sometimes muscle or nerve tests.

Is entropy always increasing?

In an isolated system, entropy tends to increase over time, making the process irreversible.

Does high entropy mean a system is more disordered?

Yes, high entropy indicates a higher level of disorder in a system.

What is muscle atrophy a common symptom of?

Muscle atrophy is a common symptom of conditions like muscular dystrophy and neuropathy.

What is the difference between disuse and neurogenic atrophy?

Disuse atrophy is due to inactivity, while neurogenic atrophy results from nerve damage.

Can atrophy affect the brain?

Yes, the brain can undergo atrophy due to various causes like Alzheimer's disease or disuse.

What is the unit of measure for entropy?

Entropy is measured in joules per kelvin (J/K).

Can entropy decrease in a system?

Entropy can decrease locally in a system if energy is inputted, but the total entropy of the universe still increases.

Is entropy a form of energy?

No, entropy is not energy; it's a measure of the dispersal of energy within a system.

Does entropy have an end point?

The end point of increasing entropy in the universe is often referred to as "heat death."
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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