What is inflammation?
What is inflammation?

What is Inflammation?

DEFINITION AND CAUSES.

Inflammation is defined as the local response of living mammalian tissues to injury dueto any agent. It is a body defense reaction in order to eliminateor limit the spread of injurious agent, followed by removal of the necrosed cells and tissues.

The agents causing inflammation may be as under:

1. Infective agents like bacteria, viruses and their toxins,fungi, parasites.

2. Immunological agents like cell-mediated and antigen antibody reactions.

3. Physical agents like heat, cold, radiation, mechanical trauma.

4. Chemical agents like organic and inorganic poisons.

5. Inert materials such as foreign bodies.Thus, inflammation is distinct from infection—whileinflammation is a protective response by the body to varietyof etiologic agents (infectious or non-infectious), while infection is invasion into the body by harmful microbes andtheir resultant ill-effects by toxins. Inflammation involves 2 basic processes with some overlapping, viz. early inflammatoryresponse and later followed by healing.

Though both these processes generally have protective role againstinjurious agents, inflammation and healing may causeconsiderable harm to the body as well e.g. anaphylaxis tobites by insects or reptiles, drugs, toxins, atherosclerosis,chronic rheumatoid arthritis, fibrous bands and adhesionsin intestinal obstruction.As discussed , “immunity or immunereaction” and “inflammatory response” by the host are both protective mechanisms in the body—inflammation is thevisible response to an immune reaction, and activation ofimmune response is almost essential before inflammatoryresponse appears.

SIGNS OF INFLAMMATION.

The Roman writer Celsusin 1st century A.D. named the famous 4 cardinal signs ofinflammation as:

rubor (redness);

tumor (swelling);

calor (heat);

and dolor (pain).

To these, fifth sign functio laesa (loss of function) was later added by Virchow. The word inflammation means burning. This nomenclature had its origin in old times butnow we know that burning is only one of the signs of inflammation.

TYPES OF INFLAMMATION.

Depending upon the defensecapacity of the host and duration of response, inflammation can be classified as acute and chronic

.A. Acute inflammation is of short duration (lasting less than2 weeks) and represents the early body reaction, resolves quickly and is usually followed by healing.

The main features of acute inflammation are:

1. accumulation of fluid and plasma at the affected site;

2. intravascular activation of platelets; and3. polymorphonuclear neutrophils as inflammatory cells.Sometimes, the acute inflammatory response may bequite severe and is termed as fulminant acute inflammation.

B. Chronic inflammation is of longer duration and occurseither after the causative agent of acute inflammation persistsfor a long time, or the stimulus is such that it induces chronicinflammation from the beginning.

A variant, chronic active inflammation, is the type of chronic inflammation in whichduring the course of disease there are acute exacerbations of activity.

The characteristic feature of chronic inflammation ispresence of chronic inflammatory cells such as lymphocytes,plasma cells and macrophages, granulation tissue formation,and in specific situations as granulomatous inflammation.In some instances, the term subacute inflammation is used for the state of inflammation between acute and chronic.facebbok

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