Final answer:
A few minutes after heart and breathing cessation, muscle movement is still possible due to residual ATP, but it will stop as ATP is depleted. Other processes cease without oxygen and nutrient supply.
Step-by-step explanation:
A few minutes after the heart stops pumping, breathing stops, and there is no evidence of brain activity, muscle movement is still possible. This phenomenon can occur due to residual ATP in the muscles, allowing for involuntary muscle contractions or reflexive twitching. However, as time passes, ATP levels deplete, leading to rigor mortis where muscles stiffen. Other processes like cellular respiration, digestion, and thought processes are dependent on the continuous supply of oxygen and nutrients, which are cut off when the heart stops beating and breathing ceases, so they will not continue post-mortem.
Requirements for Human Life
Most processes in the human body, including organization, metabolism, responsiveness, movement, growth, differentiation, reproduction, and renewal, are not consciously controlled and require a continuous supply of energy. This energy primarily comes from aerobic respiration, a process that requires oxygen to convert glucose into ATP, the energy currency of the cell. During pulmonary ventilation and external respiration, oxygen is brought into the body, allowing aerobic metabolism to proceed.