Nursing Entrance Exam (NEX) Practice Exam

Anaerobic respiration in muscle tissue occurs when oxygen levels are low, leading to the production of energy without the use of oxygen. This process typically results in the production of lactic acid as a byproduct. When lactic acid accumulates in the muscles, it can lead to muscle fatigue and discomfort, which are often experienced as cramps.

Cramps manifest because the build-up of lactic acid stimulates pain receptors in the muscles and interferes with the muscle's ability to maintain contractions effectively. This creates a sensation of tightness and pain, which is most strongly associated with anaerobic pathways being utilized due to insufficient oxygen.

While swelling, necrosis, and bleeding can occur in various pathological conditions, they are not direct results of anaerobic respiration in muscle tissue. Swelling could be a result of inflammation or injury rather than anaerobic respiration itself, necrosis generally refers to cell death due to prolonged oxygen deprivation or toxic exposure, and bleeding pertains to vascular issues or trauma. Therefore, cramps are the most immediate and relevant consequence of anaerobic respiration when oxygen is limited.