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The Immune system.

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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. ...read more.


The body must produce specific antibodies to combat every virus. Billions of viruses cover a small area the size of a pin head. Infections from these viruses can cause a variety of diseases. Including colds, polio and AIDS. Viruses are unable to reproduce on their own because they only have a few genes. They are also unable to process nutrients independently. To ensure they live and reproduce they have to invade the host cells that either die or have an abnormal function. Some viruses order the immune system to kill normal cells. The proteins surface has to attach itself to the receptor sites on the surface before the virus is able to invade. When it is attached the virus penetrates the host cell and the protein shell releases its nucleic acid. This acid uses the host cells raw material and possibly enzymes to make replicas of it. The replicated acid then generates new virus particles. The new particle makes the cell swell and therefore may cause it to burst or maybe die. If the cell bursts it releases particles that affect other cells, however not all viruses destroy cells for example the herpes virus which form buds and then removes part of the cells membrane which are known as enveloped viruses. The influenza virus has three types - A, B and C - each one is able to change its structure. Infection can re-occur when antibodies that defends the body against a previous viral structure that could be ineffective by new ones. This is called antigenic shift and occurs in antigens where the antibodies attach. ...read more.


The HIV virus destroys a certain lymphocyte, a certain white blood cell. The immune system becomes less affective as the cells decline. Eventually, after a long period of time, it will lead to death. The HIV virus is spread via sex or contaminated blood. Somebody who catches AIDS may not have any symptoms for many years and they are known as asymptomatic carriers. Towards the later stages the symptoms are weight loss, night sweats, fever and diarrhoea. When it is full on the infected person becomes susceptible to infections as well as certain cancers. If AIDS damages the immune system the lungs develop infections. Patches appear on the skin that will gradually spread to the surface of the whole body and eventually to the internal organs. It also causes diarrhoea which is the most common symptom due to infection in the gastrointestinal tract with parasites. HIV can spread to the brain and nervous system which will cause mental disturbance, vision problems leading to blindness, weakness and paralysis. The whole body and the immune system The immune systems agents are antibodies, lymphocytes, substances and cells. They are found both inside and outside of the human body and are on guard at all times. The immune system is regulated by the nervous system and the endocrine system. These in turn are influenced by the feedback from different parts of the body. SUMMARY The immune is a collection of cells that keeps a note of the pathogens that invade and it is able to destroy them. This makes the body immune to that disease. The immune system is responsible for warding of infection through the infection fighting cells and chemicals. ...read more.

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