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.

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.

Chronic Inflammation

As we have discussed on the previous page, inflammation that occurs immediately after an injury is helpful, as it protects us against infection and kick-starts the healing process. This is called acute inflammation. However, if cells are continually being damaged or are under stress and release “help me” chemicals over and over again, the resulting constant inflammatory response is not helpful. This is called chronic inflammation and is a characteristic of many conditions associated with aging.

Chronic inflammation consists of continuous attempts at construction, healing, clean-up and demolition – all occuring at the same time. This eventually results in extensive scar formation, and tissues which no longer function properly. As the nerve endings are continually being aggravated by the inflammatory chemicals, chronic inflammation can be associated with chronic pain.

Chronic Inflammatory Conditions

There are many conditions which cause ongoing stress or damage to cells and are therefore triggers of chronic inflammation. These conditions are often closely linked to one another. In some cases, having one chronic inflammatory condition puts us at higher risk of developing another. Some of the most common are mentioned below:

Obesity

When we are over-weight the fat storing cells in our body become continually overwhelmed and overstretched as they attempt to store and use large amounts of excess fat. These cells become stressed and damaged,and some may even die. They release “help me” chemicals which cause a chronic inflammatory response from the body. This results in collateral damage and further death of fat-storing cells, which are replaced with non-functional scar cells, putting more stress on the remaining fat-storing cells to store even more fat. A chronic inflammatory cycle is formed.

Smoking

When we smoke the toxic chemicals from cigarettes enters our lungs, causing stress, damage and death of lung tissue cells. Lung cells release “help me” chemicals which cause a chronic inflammatory response from the body. This results in collateral damage, and the death of many neighbouring lung cells which are replaced with non-functional scar cells, which are less elastic and do not absorb oxygen. The remaining lung cells are under more stress to provide you with the same amount of oxygen you need to survive, with less cells to do the job. A chronic inflammatory cycle is formed.

Mental Stress

When we are stressed or anxious our brain releases chemicals like adrenalin and nor-adrenalin. This can be a helpful response to a sudden, temporary stress – just before an exam, for example. Unfortunately, our stressors often last much longer than an exam. The chemicals we produce tend to stay in our bodies if we do not burn them off doing physical activity. Over time, these chemicals cause stress and damage to the cells in our blood vessel walls, and in some of the cells in our brain. These cells then send out “help me” chemicals and a chronic inflammatory response develops.

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Diabetes

People with diabetes have difficulty controlling the sugar levels in the bloodstream. High levels of sugar in the blood results in damage and stress to the cells that form the walls of our blood vessels. They release “help me” chemicals, causing a chronic inflammatory response from the body. This results in collateral damage to the cells of the vessel walls, which are then replaced with non-functional scar cells, making the vessel wall narrower, less elastic and rougher. The remaining vessel wall cells become more sensitive and more likely to be stressed and damaged. A chronic inflammatory cycle is formed.

Osteoarthritis

When we have osteoarthritis in our joints, the bone and cartilage cells have become damaged due to injuries and/or normal age-related changes. The joint becomes less good at withstanding the load of normal daily tasks and sports. As we keep using our joints, these cells become constantly stressed and damaged, and release “help me” chemicals, causing a chronic inflammatory response from the body. This results in collateral damage, and the death of more cartilage and bone cells, which are then replaced with non-functional scar cells, making the cartilage less cushioning for the joint and the bone rougher and more porous. In turn this causes even more stress to the remaining cartilage and bone. A chronic inflammatory cycle is formed.