A student asks about the common story that the majority of our cells replicate and are replaced over 7 years, which is at best a crude approximation, as the range is from a single day to many years depending on the tissue; the brain, cornea, heart, and lungs being examples of greater longevity than for many other tissues, such as in blood, skin, and the intestinal lining. Have the shorter-lived organs been weakened deliberately or through experimentation by the interlopers, to use them as multiple points of vulnerability? If so, could we strengthen our bodies by asking for specific healing for this?

By and large, there is nothing sinister in the variation of cellular lifetime among the tissues of the body. This is part of the design that some areas of the body need the capacity for regeneration because of the great stress placed on them due to their functional role. So this rapid turnover is a characteristic of cells exposed to harsh conditions such as the environment. That is why skin cells are rapidly turned over—it is because they need to regenerate and renew so much because of friction, and the possibility of many injuries of a physical nature, interacting at the surface of the body with the environment as they do. So the skin has great regenerative activity inherent with its makeup and appropriate to its function as a barrier. The same is true of the digestive tract as it is also topologically outside the body at that interface, and is subject to many adverse interactions with the environment as food is digested with harsh chemicals, and there is an interaction with a huge load of microbial life forms, many of which would happily use the tissue of the body as food, and must be warded off through chemical attack and immune cell vigilance to maintain an ongoing skirmish to keep things as peaceful as possible, but nonetheless, there is attrition with all that is happening chemically in the lumen of the gut. The lifespan tends to be longer when there is function required of a life-and-death nature or long‑term continuity, and so this is why nerve cells are so long-lived, so there is nothing mysterious about this aspect of tissue differences. There are certainly many things that have crept into the genome for a number of organs and tissues that limit lifespan and normal functioning to varying degrees as a result of genetic manipulation down through the ages by the interlopers. These do take a toll on overall longevity of the person, and occasionally, through a confluence of other sources of mutation, can become a greater liability, but this is not a general theme that affects whole organs by and large and not something that can be put into a broad scheme as outlined in the question.