Question

The muscle fatigue occurs due to accumulation of
A. $CO_2$
B. Lactic acid
C. Creatine phosphate
D. Myosin ATPase

Answer 1

Hint: Muscle cells work by sensing a flow of electrical impulses from the brain that signals these muscles to contract through the release of calcium by the sarcoplasmic reticulum.

Complete answer:
Muscle fatigue occurs due to the accumulation of lactic acid. When the supply of oxygen is less and the requirement of energy is high in the body then a high amount of lactic acid is formed.

Cause of muscle fatigue:
> The most important cause of skeletal muscle fatigue is considered as lactic acid accumulation.
> It is also caused by the need for high energy, the variation of energy needs, and an inadequate supply of oxygen.
> Fatigue can be influenced by local muscle factors, the central nervous system, and general fitness
> The type of exercise also affects fatigue, high-intensity exercise may cause muscle fatigue.
> Muscle fatigue can also occur depending on various factors that include reduced blood flow or small energy reserves because of improper diet, or metabolic disorders.
> The shortage of substrates like adenosine triphosphate (ATP), glycogen, and creatine phosphate cause metabolic fatigue.
> Accumulation of metabolites such as chloride, potassium, lactic acid, ADP, magnesium, reactive oxygen species, and inorganic phosphate can directly or indirectly lead to muscle fatigue.

Note:
- Lactic acid is a byproduct of fermentation in which cell produce energy in the absence of oxygen.
- In lactic acid fermentation, one molecule of glucose converted into two molecules of lactic acid.
- Lactic acid fermentation takes place in muscle cells.