Coastal Capital Acquisition Corp (CCAJ)

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little strange. What is rigor mortis?

Rigor mortis refers to the state of a body after death, in which the muscles become stiff. It commences after around 3 hours, reaching maximum stiffness after 12 hours, and gradually dissipates until approximately 72 hours after death. Rigor mortis occurs due to changes in the physiology of muscles when aerobic respiration ceases.

Muscles are made up of two types of fibre. These fibres have connections between them that lock and unlock during muscle contraction and relaxation. These connections are controlled by a biochemical pathway within the cell, which is partially driven by the presence of calcium ions. The concentration of calcium ions is higher in the fluid surrounding muscle cells than it is inside the cells, so calcium tends to diffuse into the cell. High calcium levels inside the cell drive the biochemical pathway in the direction that maintains muscle contraction. To relax, muscle cells must expel the calcium ions from the cell and this requires energy molecules to pump them across the cell membrane.

After a body has died, the chemical reaction producing these energy molecules is unable to proceed because of a lack of oxygen. The cells no longer have the energy to pump calcium out of the cell and so the calcium concentration rises, forcing the muscles to remain in a contracted state. This state of muscle stiffening is known as rigor mortis and it remains until the muscle proteins start to decompose.