WebMD explains inflammation, a process by which the body's immune system malfunctions. Find out how it is associated with arthritis and. WebMD explains what inflammation is and how it affects your body. Inflammation indicates that the body is fighting something harmful and trying to heal itself. It can be short-term and acute or longer-term and.
In some instances inflammation can cause harm. Tissue destruction can occur when the regulatory mechanisms of the inflammatory response are defective or the ability to clear damaged tissue and foreign substances is impaired.
In other cases an inappropriate immune response may give rise to a prolonged and damaging inflammatory response. Although acute inflammation is usually beneficial , it often causes unpleasant sensations, such as the pain of a sore throat or the itching of an insect bite. Discomfort is usually temporary and disappears when the inflammatory response has done its job. But in some instances inflammation can cause harm. Whenever cells are damaged or destroyed, a series of vascular and cellular events known as the inflammatory response is set in motion.
This response is protective of health in that it destroys or walls off injurious influences and paves the way for the…. The factors that can stimulate inflammation include microorganisms, physical agents, chemicals, inappropriate immunological responses, and tissue death. Infectious agents such as viruses and bacteria are some of the most common stimuli of inflammation.
Viruses give rise to inflammation by entering and destroying cells of the body; bacteria release substances called endotoxins that can initiate inflammation.
Physical trauma, burns, radiation, and frostbite can damage tissues and also bring about inflammation, as can corrosive chemicals such as acids, alkalis, and oxidizing agents.
As mentioned above, malfunctioning immunological responses can incite an inappropriate and damaging inflammatory response. Inflammation can also result when tissues die from a lack of oxygen or nutrients, a situation that often is caused by loss of blood flow to the area.
The four cardinal signs of inflammation—redness Latin rubor , heat calor , swelling tumor , and pain dolor —were described in the 1st century ad by the Roman medical writer Aulus Cornelius Celsus. Redness is caused by the dilation of small blood vessels in the area of injury. Heat results from increased blood flow through the area and is experienced only in peripheral parts of the body such as the skin.
Fever is brought about by chemical mediators of inflammation and contributes to the rise in temperature at the injury. Swelling, called edema , is caused primarily by the accumulation of fluid outside the blood vessels. The pain associated with inflammation results in part from the distortion of tissues caused by edema, and it also is induced by certain chemical mediators of inflammation, such as bradykinin, serotonin , and the prostaglandins.
A fifth consequence of inflammation is the loss of function of the inflamed area, a feature noted by German pathologist Rudolf Virchow in the 19th century. Loss of function may result from pain that inhibits mobility or from severe swelling that prevents movement in the area. When tissue is first injured, the small blood vessels in the damaged area constrict momentarily, a process called vasoconstriction.
Following this transient event, which is believed to be of little importance to the inflammatory response, the blood vessels dilate vasodilation , increasing blood flow into the area. Vasodilation may last from 15 minutes to several hours. Next, the walls of the blood vessels, which normally allow only water and salts to pass through easily, become more permeable. Protein-rich fluid, called exudate, is now able to exit into the tissues. Substances in the exudate include clotting factors, which help prevent the spread of infectious agents throughout the body.
Other proteins include antibodies that help destroy invading microorganisms. As fluid and other substances leak out of the blood vessels, blood flow becomes more sluggish and white blood cells begin to fall out of the axial stream in the centre of the vessel to flow nearer the vessel wall.
The white blood cells then adhere to the blood vessel wall, the first step in their emigration into the extravascular space of the tissue. The most important feature of inflammation is the accumulation of white blood cells at the site of injury. The main phagocytes involved in acute inflammation are the neutrophils , a type of white blood cell that contains granules of cell-destroying enzymes and proteins.
When tissue damage is slight, an adequate supply of these cells can be obtained from those already circulating in the blood. But, when damage is extensive, stores of neutrophils—some in immature form—are released from the bone marrow , where they are generated. To perform their tasks, not only must neutrophils exit through the blood vessel wall but they must actively move from the blood vessel toward the area of tissue damage.
This movement is made possible by chemical substances that diffuse from the area of tissue damage and create a concentration gradient followed by the neutrophils. The substances that create the gradient are called chemotactic factors, and the one-way migration of cells along the gradient is called chemotaxis.
Ever wonder why your skin becomes red and hot and swells after an injury? Learn about the process of inflammation and how it contributes to swelling. Large numbers of neutrophils reach the site of injury first, sometimes within an hour after injury or infection. After the neutrophils, often 24 to 28 hours after inflammation begins, there comes another group of white blood cells, the monocytes , which eventually mature into cell-eating macrophages.
Macrophages usually become more prevalent at the site of injury only after days or weeks and are a cellular hallmark of chronic inflammation. Although injury starts the inflammatory response, chemical factors released upon this stimulation bring about the vascular and cellular changes outlined above. The chemicals originate primarily from blood plasma , white blood cells basophils, neutrophils, monocytes, and macrophages , platelets , mast cells , endothelial cells lining the blood vessels, and damaged tissue cells.
One of the best-known chemical mediators released from cells during inflammation is histamine , which triggers vasodilation and increases vascular permeability.
Stored in granules of circulating basophils and mast cells, histamine is released immediately when these cells are injured. Other substances involved in increasing vascular permeability are lysosomal compounds , which are released from neutrophils, and certain small proteins in the complement system, namely C3a and C5a. Many cytokines secreted by cells involved in inflammation also have vasoactive and chemotactic properties.
The prostaglandins are a group of fatty acids produced by many types of cells. Some prostaglandins increase the effects of other substances that promote vascular permeability.
Others affect the aggregation of platelets, which is part of the clotting process. Prostaglandins are associated with the pain and fever of inflammation. Anti-inflammatory drugs , such as aspirin , are effective in part because they inhibit an enzyme involved in prostaglandin synthesis.
Prostaglandins are synthesized from arachidonic acid, as are the leukotrienes, another group of chemical mediators that have vasoactive properties. The plasma contains four interrelated systems of proteins— complement , the kinins , coagulation factors , and the fibrinolytic system —that generate various mediators of inflammation. Activated complement proteins serve as chemotactic factors for neutrophils, increase vascular permeability, and stimulate the release of histamine from mast cells.
They also adhere to the surface of bacteria, making them easier targets for phagocytes. The kinin system, which is activated by coagulation factor XII, produces substances that increase vascular permeability. The most important of the kinins is bradykinin, which is responsible for much of the pain and itching experienced with inflammation. The coagulation system converts the plasma protein fibrinogen into fibrin , which is a major component of the fluid exudate. The fibrinolytic system contributes to inflammation primarily through the formation of plasmin, which breaks down fibrin into products that affect vascular permeability.
Once acute inflammation has begun, a number of outcomes may follow. These include healing and repair, suppuration, and chronic inflammation. The outcome depends on the type of tissue involved and the amount of tissue destruction that has occurred, which are in turn related to the cause of the injury. Different types of cells vary in their ability to regenerate.
Some cells, such as epithelial cells, regenerate easily, whereas others, such as liver cells, do not normally proliferate but can be stimulated to do so after damage has occurred. Still other types of cells are incapable of regeneration. For regeneration to be successful, it is also necessary that the structure of the tissue be simple enough to reconstruct.
For example, uncomplicated structures such as the flat surface of the skin are easy to rebuild, but the complex architecture of a gland is not. In some cases, the failure to replicate the original framework of an organ can lead to disease. This is the case in cirrhosis of the liver, in which regeneration of damaged tissue results in the construction of abnormal structures that can lead to hemorrhaging and death.
Repair, which occurs when tissue damage is substantial or the normal tissue architecture cannot be regenerated successfully, results in the formation of a fibrous scar.
Through the repair process, endothelial cells give rise to new blood vessels, and cells called fibroblasts grow to form a loose framework of connective tissue. This delicate vascularized connective tissue is called granulation tissue. It derives its name from the small red granular areas that are seen in healing tissue e.
As repair progresses, new blood vessels establish blood circulation in the healing area, and fibroblasts produce collagen that imparts mechanical strength to the growing tissue. Eventually a scar consisting almost completely of densely packed collagen is formed. The volume of scar tissue is usually less than that of the tissue it replaces, which can cause an organ to contract and become distorted.
Some of the best sources of omega-3s are cold water fish, such as salmon and tuna, and tofu, walnuts, flax seeds and soybeans. Other anti-inflammatory foods include grapes, celery, blueberries, garlic, olive oil, tea and some spices ginger, rosemary and turmeric. The Mediterranean diet is an example of an anti-inflammatory diet.
This is due to its focus on fruits, vegetables, fish and whole grains, and limits on unhealthy fats, such as red meat, butter and egg yolks as well as processed and refined sugars and carbs. Inflammatory foods include red meat and anything with trans fats, such as margarine, corn oil, deep fried foods and most processed foods. Limit or avoid simple carbohydrates, such as white flour, white rice, refined sugar and anything with high fructose corn syrup.
One easy rule to follow is to avoid white foods, such as white bread, rice and pasta, as well as foods made with white sugar and flour. Build meals around lean proteins and whole foods high in fiber, such as vegetables, fruits and whole grains, such as brown rice and whole wheat bread. Make time for 30 to 45 minutes of aerobic exercise and 10 to 25 minutes of weight or resistance training at least four to five times per week.
Chronic stress contributes to inflammation. Use meditation, yoga, biofeedback, guided imagery or some other method to manage stress throughout the day. Follow these six tips for reducing inflammation in your body: People who are overweight have more inflammation. Losing weight may decrease inflammation.
Inflammation is a vital part of the immune system's response to injury and infection. It is the body's way of signaling the immune system to heal. Learn how inflammation, the natural defense mechanism of the body to protect against foreign invaders or injury, can become chronic in some. What you eat can have a big effect on inflammation in your body. This article outlines an anti-inflammatory diet plan that is based on science.