The existence of the human body, the continuation of our life and the survival of human race, are all dependent on the ability of the body to heal itself. Our body faces wear and tear on an almost regular basis, with multitudes of injuries affecting the cells, the tissues and the organs every day, and yet we are able to carry on, almost unaware of all the damages happening within, only because the body is able to take care of all of those injuries, wear and tear at a matching pace. The body heals itself as part of normal living, without any conscious effort from our side except probably to get the requisite rest and nutrition that enables it to resurrect new cells and tissues from the proteins and lipid of our diet.
HEALING FROM MICRO CELLULAR PROCESSES TO MACRO HEALING
Healing can be defined as the process by which an altered state of body is brought back to its normal condition. The body is made of organs, which are in turn made of tissues and cells. Healing takes place at many levels simultaneously.
The most primary level is within the cell itself. A cell is a dynamic living unit whose condition keeps varying continuously. The cells get disturbed and injured regularly and have an ability to 'heal' themselves by changing back to their original shape. The injuries faced by the cells often result from free radicals, partially oxidized molecules like superoxide' and hydrogen peroxide' which are unstable and damage the proteins and lipids of cells by chemically reacting with them. This damage is prevented within the cells by ANTIOXIDANTS, which combine with free radicals and neutralise them. The damaged proteins and lipids are separately repaired by complex metabolic processes using a variety of enzymes and metabolites.
In addition to intracellular healing, the body also has an ability to make new cells to replace cells that have been permanently damaged and destroyed. Even when a large number of cells, say a few hundred thousands, are destroyed, as happens almost on a regular daily basis, the surrounding cells replicate to make new cells to replace these cells almost immediately. This process also keeps happening even without our realizing it.
This process of healing is an essential ingredient of life. Unless the body had the capacity to heal, life could never exist, and this capacity is an inherent ingredient of the body, independent of any external support of medicines.
THE STEPS IN BODY HEALING
Body's healing consists of a process to replace the dead cells and tissues with identical ones. It is a complex process that takes place in several steps at various levels.
The immediate response of body to the external or internal injury that is big enough to cause bleeding consists primarily of steps to stop bleeding. Bleeding is stopped by the contraction of blood vessels within a couple of minutes. This is followed by a complex process by which blood clots are built up to block the injury that is causing the blood to leak. This process of blood clotting begins with aggregation of platelets at the site of injury, and ends with formation of a blood clot that blocks the external oozing of blood.
The repair of the tissue needs formation of new cells. The white blood cells accumulate at the site of injury, and begin to destroy and digest the dead cells there by the secretion of special enzymes that are stored in small packets called lysosomes' in those cells. They remove the debris and create space which new cells can occupy.
Simultaneously, the process of new cell formation begins from the latest layer of cells of that tissue, while the older cells are pushed to the site of injury, gradually filling the space created by dead cells. When there is a big gap between the living tissues at the place of injury, the space is initially filled with blood clot, and then a fibrous material is deposited there, a process known as FIBROSIS, which leads to a scar. This fibrous tissue shrinks during the next few months, but may never disappear completely.
Healing is a highly self regulated process that never proceeds beyond the needs of the body. It allows fine tuning of various processes of cell repair and new cell formation with the process of removal of dead cells and fibrous tissue. It takes place in such a coordinated manner that integrity of the injured body part is not compromised and in the meantime we can continue to carry on with our normal life.
In addition to repair of major injuries, healing also takes care of usual wear and tear of the body, a process that is actually far more important for continuation of life. The human body does not require servicing, because it can heal its minor injuries without having to make any conscious efforts for the same. Healing thus includes replacing dead cells of the skin, mouth, intestines and blood that are damaged and destroyed in very large numbers every day. Most of these cells need to be replaced in great numbers every day and the body actually keeps on churning out new cells to replace the dead ones on a regular basis.
Healing is a complex process of repair of cells as well as replacement of dead cells that leads to healing of the tissues. All cells of the body cannot be replaced. One example is central neurons of brain and spinal cord, which once damaged cannot be replaced. Fortunately for us, most other cells can be replaced and most injuries can be healed to a large extent. Healing is an essential characteristic of the human body that allows us to live in spite of minor damages and injuries to our body. Without it, life could never have survived for long.