Following stoppage of heart, lungs and brain, blood and oxygen supply to cells cease. The cells then use anaerobic pathways until their metabolic reserves are exhausted and slowly begin to die.
Loss of brain activity results in absent reflexes. Corneal reflex ceases and pupil become non-reactive to light. Retinal vessels when viewed under ophthalmoscope will show fragmentation of blood inside retinal vessels, called trucking or shunting of retinal vessels. Intra-ocular pressure drops resulting in flaccid appearance of the eyeball. Absence of blood pressure results in pale conjunctiva, skin and mucous membrane.
In case of asphyxial deaths, face and lips appear blue.
Rigor mortis in small muscles around hair follicles will result in prominence of hair and beard after death, which is usually misunderstood as growth after death.
Loss of muscle tone during the period of primary flaccidity may result in voiding of urinary bladder or emission of semen, which should be considered as artefact. Regurgitated food particles found in the airways should be examined carefully as they may be found in a significant number of autopsies. Cause of death should ideally be diagnosed to be choking or aspiration only after microscopic examination of peripheral airway terminals.