The Immune system.

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Deborah Peters                                                                                                                           Page         

Student Number: cm09xp9897, Course Title: Beauty Therapy, Assignment 2

The Immune system

The immune system is a network of organs that contain cells which recognize foreign substances and destroys them. All living organisms are exposed to harmful substances and most can protect themselves in several ways, either with physical barriers or chemicals that repel and kill them. It protects vertebrates against viruses, bacteria, fungi and other parasites. These viruses are called pathogens.

The immune system is known to help in the fight against cancer. A type of white cell, which is called the killer cells, is able to identify tumour cells simply by its change in its surface membrane. Other cells, called the helper cells, assist the killers to multiply and they then connect themselves to the cancerous cells to destroy them.

There are two types of defence – the innate and the adaptive. The innate includes barriers like the skin and antibacterial enzymes within tears. The adaptive is based on specialized white blood cells which are lymphocytes and they respond to invasions by micro-organisms. Antibodies are chemicals produced by B cells, they circulate in the blood that attacks disease and causes organisms, T cells attack organisms head on, and these cells can memorize earlier infections and therefore can act fast to avoid further attacks. The defence of the immune system helps to provide protection against infectious disease as well as some malfunctions of the internal body.

If the infectious organism splits the skin or maybe one that is not killed off by chemicals, for example the enzymes found in tears or the saliva, the immune and inflammatory response come into action. Some of the signs of fighting infection are fever, swelling and pain, this is due to several of the white cells trying to prevent the spread of infection.

Inflammatory response

Diseased organisms trigger the inflammatory response off in the affected tissues. It is a non-specific defence which attacks invading organisms. Blood flow increases and neutrophil cells ingest and destroy organisms.

The invading organisms damage the tissues so they release prostaglandins and histamine. They not only attract neutrophil cells they also cause pain and swelling.

Student Number: cm09xp9897, Course Title: Beauty Therapy, Assignment 2

The neutrophils in other parts of the body are attracted by poisons which are produced by organisms. They can get through the tiniest of places in the blood vessel walls to enable it to reach the injured tissues.

Antibodies are proteins which are specially created to attach themselves to the invading organisms. Antibodies are recognized by their receptors, the antibody and the diseased organisms attach themselves to the neutrophils. The neutrophils form pseudopods which swallow up the organisms. Once ingested the organisms become isolated in the phagolysosome, which is a type of cell. This is known as phagocytosis.

The substances which have broken down the organisms drain into the phagolysosome. The undigested parts of organisms can be either excreted at the cell membrane or stored.

The non-specific inflammatory response can prevent the spread of infection. However, if infection does spreads there are two defences – an antibody or a cellular defence. These are known as the immune response. They rely on the actions of the white blood cells, T and B lymphocytes and they provide protection against any future infections.

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B Lymphocytes   

They recognize foreign proteins from the disease organisms, these are known as the antigens, which differ from the natural bodies protein. The antigens trigger the B cells to enable them to multiply. They begin as stem cells in the bone marrow and then develop into lymph nodes.

T Lymphocytes

They attach themselves to the infected target cells after they have recognized the antigens on the surface. The T cells attack cancer cells to enable the tumours growth to become slower. They are able to survive for several years to allow it to respond if an ...

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