Body > What is inflammation?

What is inflammation?

Inflammation is triggered when our body is damaged, and is an important part of our immune response. This damage can be from a new injury or from the aggravation of an ongoing condition. Inflammation not only happens when there is damage to body parts we can see, like muscles or joints, but also with damage at a microscopic, cellular level that we can’t see. This inflammatory response is important in protecting us from infection and promoting healing, but it is very general and may be out of proportion to the extent of the damage. 

When any part of our body is injured it releases “help me” chemicals that cause our body to mount an inflammatory response.  The following events occur:

  • The blood vessels around the damage dilate (become larger), increasing blood flow to the injured area – this causes visible redness and warmth in the area. 
  • The walls of the same blood vessels also become more permeable.  This allows nutrient-rich fluid to make its way into the area around the damage. The fluid contains useful things like construction and healing cells, demolition and clean up cells and inflammatory chemicals, but it also  causes swelling and joint stiffness. 
  • The clean-up and demolition cells are a type of white blood cell.  They take away the damaged tissue to make way for healing and repair.  
  • These clean-up and demolition cells also release messenger chemicals. Your immune system picks up on these signals, and specialised immune cells will be  attracted to the area to fight off any potential infection that might have got in when you were injured. 
  • The construction cells lay down temporary ‘Band-Aid’ cells to quickly mend the injury. 
  • Most of these temporary cells are gradually replaced with more functional cells of the same type as the injured tissue; eg. bone, muscle, tendon or skin. 
  • Some scar tissue will remain that is not the same as the tissue around it, and does not function like the original cells did. 

The chemicals released during this process may irritate the nerve endings in the area, which then send signals up the brain.  If the brain interprets these signals as a warning of danger, the pain alarm system may be triggered.

Photo by nebari/iStock / Getty Images
Photo by nebari/iStock / Getty Images

Collateral Damage

This inflammatory response is very general and widespread, and while it is quite effective at stopping infection and clearing away damaged tissue, there is some risk of collateral damage. Instead of clearing away only those cells which are dead or damaged, it may also attack and clears away healthy cells near the injured area. Instead of releasing chemicals that only target and kill nasty bacteria, it may release  an abundance of chemicals that damage nearly everything in the area. 

This means that every time inflammation occurs, some healthy tissue is also damaged and lost, to be replaced with new tissue and scar tissue.