Immune System

the natural defense system, present in the body of a VERTEBRATE animal which helps to protect it against diseases caused by micro-organisms and parasites. There are two types of immunity provided by the immune system:

1) natural (known as innate)--this is present from birth and is wide ranging, operating against almost any foreign substance that threatens the body.

2) acquired immunity--this type of immunity occurs as a result of an attack by a particular foreign substance. The immune system builds up its defenses against that particular substance and uses them again in any future attack.

Taken from Dictionary of Science

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An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumour cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own healthy cells and tissues in order to function properly. Detection is complicated as pathogens can evolve rapidly, producing adaptations that avoid the immune system and allow the pathogens to successfully infect their hosts.

To survive this challenge, multiple mechanisms evolved that recognize and neutralize pathogens. Even simple unicellular organisms such as bacteria possess enzyme systems that protect against viral infections. Other basic immune mechanisms evolved in ancient eukaryotes and remain in their modern descendants, such as plants and insects. These mechanisms include antimicrobial peptides called defensins, phagocytosis, and the complement system. Jawed vertebrates, including humans, have even more sophisticated defense mechanisms. The typical vertebrate immune system consists of many types of proteins, cells, organs, and tissues, which interact in an elaborate and dynamic network. As part of this more complex immune response, the human immune system adapts over time to recognize specific pathogens more efficiently. This adaptation process is referred to as "adaptive immunity" or "acquired immunity" and creates immunological memory. Immunological memory created from a primary response to a specific pathogen, provides an enhanced response to secondary encounters with that same, specific pathogen. This process of acquired immunity is the basis of vaccination.

Disorders in the immune system can result in disease. Immunodeficiency occurs when the immune system is less active than normal, resulting in recurring and life-threatening infections. Immunodeficiency can either be the result of a genetic disease, such as severe combined immunodeficiency, or be produced by pharmaceuticals or an infection, such as the acquired immune deficiency syndrome (AIDS) that is caused by the retrovirus HIV. In contrast, autoimmune diseases result from a hyperactive immune system attacking normal tissues as if they were foreign organisms. Common autoimmune diseases include Hashimoto's Thyroiditis, rheumatoid arthritis, diabetes mellitus type 1 and lupus erythematosus. Immunology covers the study of all aspects of the immune system which has significant relevance to human health and diseases. Further investigation in this field is expected to play a serious role in promotion of health and treatment of diseases.

Taken from Wikipedia

Background

'interference' which affects the reading of a signal that is being measured. The interference signals come from sources such as natural RADIOACTIVITY and COSMIC RAYS and must be allowed for when measurements are being taken.

Taken from Dictionary of Science

Earthquake! What You Can Do to Protect Yourself

Mention the word earthquake and it strikes fear into the hearts of many. Few natural disasters are as terrifying. Few hit so suddenly and swiftly.

Experts tell us that a big one may soon occur in almost any part of the world. Are you ready for it?

After a major quake, telephone service will probably be cut off. Roads will be destroyed. For the first few hours, the victims will have to fend for themselves. Sometimes help may only arrive days later. To reduce injuries, suffering and even deaths, it is crucial that every family be prepared.

How can you help? Why not discuss the following suggestions with your family over dinner? Experts advice each family to have the following minimum preparations:

1. Large objects should be strapped down or bolted to the wall. Pay particular attention to the water heater. If it tips, it could break a gas line, possibly leading to a fire.

2. Have an evacuation plan for every member of your family during and after an earthquake. During a quake, seek protection under a solid table or by sitting on the floor of a hallway, bracing yourself against the walls and covering your head. Only stand in a doorway that has no door--a door could swing shut and crush your fingers. Do not run outside as you may be hit by falling objects. If you are outside, run to a clear, open space, away form any objects that could fall. As soon as the shock has stopped, walk to a preselected place to meet other family members.

3. Put away at least a three-day supply of food and drinking water. Remember the food you store will go bad after some time. So be sure to change it with a new batch when it reaches its shelf life. If you store canned food, remember to provide a can opener!

4. Have an earthquake kit that includes a first-aid kit, one or more flashlights, a battery-powered radio, extra batteries and a blanket.

5. Each family member who is old enough should know how to turn off the gas, water and electrical supply.

Preparation is the best defense. If you are living in an earthquake zone, think about being prepared. For more information, contact the fire department, an emergency relief agency such as the Red Cross Society or look for special booklets on preparing for an earthquake at your library or bookstore.

- By Keok C. Tan

Taken from Youth 90 magazine