18/07/2022
This explains what is inflamation
š INFLAMMATION: TISSUE RESPONSE TO INJURY
The inflammatory response is a natural defence mechanism that is triggered whenever body tissues are damaged in any way. Most of the body defence elements are located in the blood and inflammation is the means by which body defence cells and defence chemicals leave the blood and enter the tissue around the injured or infected site. Inflammation occurs in response to physical trauma, intense heat and irritating chemicals, as well as to infection by viruses and bacteria.
The inflammatory response:
1. prevents the spread of damaging agents to nearby tissues
2. disposes of cell debris and pathogens
3. sets the stage for the repair process.
The four cardinal signs of inflammation are redness, heat, swelling and pain. Many experts consider impairment of function to be the fifth cardinal sign of inflammation.
The inflammatory process begins with chemical āalarmsā a series of inflammatory chemicals that are released in the extracellular fluid. Injured tissue cells, phagocytes, lymphocytes, mast cells and blood proteins are all sources of inflammatory mediators, the most important of which are histamine, kinins, prostaglandins, complement, and lymphokines.
Though some of these mediators have individual inflammatory roles as well, they all promote dilation of the small blood vessels in the vicinity of the injury. As more blood flows into the area local hyperemia (congestion with blood) occurs which accounts for the redness and the heat of the inflamed area.
These chemicals also increase the permeability of local capillaries. Consequently, exudates, fluid containing proteins such as clotting factors and antibodies, seeps from the bloodstream into the tissue spaces.
This exudate is the cause of the local oedema or swelling that in turn, presses on adjacent nerve endings, contributing to a sensation of pain. Pain also results from the release of bacterial toxins, lack of nutrition to the cells in the area, and the sensitising effects of released prostaglandins and kinins. If the swollen and painful area is a joint, normal movement may be inhibited temporarily in order for proper healing and repair to occur.
Although at first, oedema may seem to be detrimental to the body, it isnāt. The entry of protein-rich fluids into the tissue spaces helps to dilute harmful substances, which may be present, brings in large quantities of oxygen and nutrients necessary for the repair process, and allows the entry of clotting proteins which form a gel like fibrin mesh in the tissue space that effectively isolates the injured area and prevents the spread of bacteria and other harmful agents into the adjacent tissues. It also forms a scaffolding for permanent repair.
