A 50-year-old overweight male with a history of atherosclerosis, diabetes mellitus type 2, and coronary artery disease (CAD) is found by a neighbor unconscious and not breathing in his front lawn where he appears to have been mowing his lawn. He is rushed to a local emergency room where it is determined that he has suffered a massive inferior myocardial infarction. He is sent to the intensive care unit in critical condition where he is placed on advanced life support equipment, and several days later it is determined that he has minimal brain activity.
Explain the pathophysiology of how cardiac arrest (myocardial infarction) leads to brain death? What happens in the nervous system?