Due to glycolysis in post mortem muscles there is accumulation of?

SJH Nursing Officer - 2019

Biochemistry & Nutrition

Medium

Appeared in: SJH Nursing Officer - 2019

Explanation

After death, the cessation of blood circulation leads to an oxygen-deficient (anaerobic) environment in the muscles.
To produce energy (ATP), muscle cells switch to anaerobic glycolysis, breaking down glycogen.
Lactic acid is the end product of anaerobic glycolysis.
Without blood circulation to clear it, lactic acid accumulates in the muscle tissue.
This accumulation lowers the muscle pH, contributing to the development of rigor mortis.

Option A: Carbon is a fundamental element in organic molecules like glucose and lactic acid, but it is not the specific metabolic product that accumulates. The question asks for the compound that builds up.
Option C: Oxygen is what becomes unavailable after death due to the cessation of breathing and circulation. Its absence is the trigger for anaerobic glycolysis, not a product of it.
Option D: Blood circulation ceases post-mortem. While blood is present in the vessels, it does not 'accumulate' in the muscles as a result of glycolysis. Instead, it pools in dependent parts of the body due to gravity, a process called livor mortis.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Post-mortem muscle metabolism and the process of anaerobic glycolysis as background academic context rather than a clinical decision trigger.
Understanding post-mortem changes, including the biochemical basis of rigor mortis (lactic acid accumulation and ATP depletion), is crucial in forensic medicine to estimate the time of death.
The rate of rigor mortis development and resolution is influenced by factors like ambient temperature, the person's muscle mass, and the cause of death, providing valuable clues for investigators.
What if? - If the individual died during strenuous exercise, the onset of rigor mortis would be faster. This is because their muscles would already have depleted ATP stores and accumulated some lactic acid before death, accelerating the post-mortem process.

How to Approach the Question

First, identify the key terms in the question: 'post mortem' (after death), 'glycolysis', and 'accumulation'.
Recall the two main types of glycolysis: aerobic (with oxygen) and anaerobic (without oxygen).
Recognize that 'post mortem' implies a lack of oxygen because breathing and circulation have stopped.
Connect the lack of oxygen to anaerobic glycolysis.
Remember the end product of anaerobic glycolysis in muscle cells is lactic acid.
Conclude that since circulation has stopped, this lactic acid cannot be cleared and will therefore accumulate.

Concept Tested & Keywords

Concept Tested: Post-mortem muscle metabolism and the process of anaerobic glycolysis.
Stem keywords: glycolysis, post mortem, muscles, accumulation
Lead-in keywords: BEST, MOST RELEVANT CLUE
Negative lead-in flag: false

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E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 1 (pp 26-370 of 370) pp. 149-151, 199-201, 157-159