Blood
By
Gary Jones
Components of the blood.
The Immune System
The immune system is a group of cells, molecules, and tissues that help
defend the body against diseases and other harmful invaders. The immune system
provides protection against a variety of potentially damaging substances that
can invade the body. These substances include disease-causing organisms, such
as bacteria, fungi, parasites, and viruses. The body's ability to resist these
invaders is called immunity. A key feature of the immune system is its ability
to destroy foreign invaders while leaving the body's own healthy tissues alone.
Sometimes, however, the immune system attacks and damages these healthy tissues.
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The Immune System
The immune system is a group of cells, molecules, and tissues that help
defend the body against diseases and other harmful invaders. The immune system
provides protection against a variety of potentially damaging substances that
can invade the body. These substances include disease-causing organisms, such
as bacteria, fungi, parasites, and viruses. The body's ability to resist these
invaders is called immunity. A key feature of the immune system is its ability
to destroy foreign invaders while leaving the body's own healthy tissues alone.
Sometimes, however, the immune system attacks and damages these healthy tissues.
This reaction is called an autoimmune response or autoimmunity.
A virus is a submicroscopic infectious particle composed of a protein coat and a nucleic acid core. Viruses, like cells, carry genetic information encoded in their nucleic acid, and can undergo mutations and reproduce; however, they cannot carry out metabolism, and thus are not considered alive. Viruses are classified by the type of nucleic acid they contain, and the shape of their protein capsule.
The immune system is composed of many parts that work together to fight
infections when pathogens or poisons invade the human body. Pathogens are
disease-causing organisms such as bacteria and viruses. The immune system reacts to foreign substances through a series of steps know as the immune response. Any agent perceived as foreign by a body's immune system is called an antigen. Several types of cells may be involved in the immune response to antigens.
When an antigen enters the body, it may be partly neutralized by components of the innate immune system. It may be attacked by phagocytes or by preformed antibodies that act together with the complement system. The human immune system contains approximately 1 trillion T cells and 1 trillion B cells, located in the lymphoid organs and in the blood, plus approximately 10 billion antigen-presenting cells located in the lymphoid organs. To maximize the chances of encountering antigens wherever they may invade the body, lymphocytes continually circulate between the blood and certain lymphoid tissues. A lymphocyte spends an average of 30 minutes per day in the blood and re-circulates about 50 times per day between the blood and lymphoid tissues.
Lymphocytes are special types of white blood cells. Like other white blood cells, lymphocytes originate in the bone marrow, the blood-forming tissue in the centre of many bones. Some lymphocytes mature in the bone marrow and become B lymphocytes, also know as B cells. The B stands for bone marrow derived. Some of these cells develop into plasma cells, which produce
antibodies. Antibodies are proteins that attack antigens. They are carried in the blood, in tears, and in secretions of the nose and the intestines. Other lymphocytes do not mature in the bone marrow. Instead, they travel through the bloodstream to the thymus, an organ in the upper chest. In the thymus, the immature lymphocytes develop into T lymphocytes, also knows as T cells. The T stands for thymus derived. The B lymphocytes are responsible for the production of the blood-serum components called immunoglobulin. The T lymphocytes are responsible for attacking and killing antigens directly. Both the T and the B lymphocytes have the ability to remember previous exposure to a specific antigen, so that if the same antigen enters the body the T and B lymphocytes can take faster and better action against it.
There are many disorders that disrupt the immune system's operations. The most serious are the disorders called immunodeficiency diseases, such as AIDS. These diseases can lead to death. Immunodeficiency diseases are among the most severe disorders of the immune system. People afflicted with such conditions lack some basic feature or function of their immune system. As a result, their immune system fails to respond adequately to harmful invaders. For this reason, people with immune deficiency diseases suffer from different kinds of illness.
Allergies are mistaken and harmful responses of the body's immune system
to substances that are harmless to most people. The substances that provoke an
Allergic reaction, are called allergens. They include pollen, dust, and Feathers. Among the common allergic diseases are asthma, eczema, which is an Itchy red swelling of the skin, hay fever, and hives.
If lymphocytes encounter an antigen trapped by the antigen-presenting
cells of the lymphoid organs, lymphocytes with receptors specific to that
Antigen stop their migration and settle to mount an immune response locally.
The process of inducing an immune response is called immunisation. It may be
either natural, through infection by a pathogen, or artificial, through the use
of serums or vaccines. The immune system cannot always protect the body from diseases
by itself, sometimes it needs help.
Doctors give their patients vaccines to
help protect them from certain severe, life-threatening infections. Vaccines
and serums boost the body's ability to defend itself against particular types of
viruses or bacteria.
To keep our immune system healthy, a very often overlooked problem is that of what we eat. It is vitally important that we consume the correct foods to keep our immune system in good working order. Many common foods have potent immunity-boosting properties when consumed regularly in sufficient quantities, including the following:
Cruciferous vegetables
The members of this family of vegetable, including broccoli, cauliflower, cabbage, Brussels sprouts, and turnips, are rich in beta-carotene and protect mucous membranes, especially in the lungs and intestinal tract, from cancer and free-radical damage.
Garlic
Garlic is probably the foremost immune-enchanting food on Mother Nature's menu. It has a wider spectrum of antibiotic activity than penicillin, inhibits many viruses and helps prevent cancer. It is also one of the richest natural sources of selenium, which is required to produce the potent antioxidant enzyme gluthione peroxidase. It is most effective when consumed raw.
Raw fish
Deep-water fish such as salmon and tuna are rich sources of omega-3 fish oils, which contain the essential fatty acids required to produce immune factors such as white blood cells in the body. They also prevent heart attacks by keeping the arteries clear of cholesterol deposits. These elements are most abundant and easy to assimilate when the fish is consumed raw, but if you prefer it cooked, then lightly steam or poach it.
Seaweed's
Seaweed's are known to lower blood cholesterol, neutralise radiation toxicity and enhance overall immunity.
Raw almonds
Raw almonds are one of the best natural sources of essential amino acids and essential fatty acids, both of which are required for optimum immunity.
For vegetarians, who often become deficient in these vital nutrients, raw almonds are an excellent substitute for meat and other animal products.
Bee pollen
Another good source of essential fatty acids, bee pollen is also loaded with enzymes and other potent nutritional elements which boost immunity. Pollen also helps eliminate many food allergies.
Although these are only a few of the foods we can eat there are many more. This could be difficult to work out the correct quantities. We can use supplements to replace some of the missing foods as a cheaper and more convenient alternative. This is also helpful for people whose life style does not allow them the time to eat regular healthy meals.
Many vitamins function not only as nutrients, but also as potent antioxidants.
When the body is stressed, it utilizes vitamins at a far greater rate than under normal conditions, a fact that shows how important these nutrients are to immune functions.
Most important is vitamin C, which helps prevent cancer, counteracts the immunosuppressive effects of cortisone, protects the heart and boosts overall immunity. The optimum maintenance dose is 2-6 grams per day and double that amount when ill.
Other immunity-boosting vitamins include, in order of potency, vitamins A (preferably as beta-carotene), vitamin E and vitamin B1, B5, B6, and B12.
Minerals
The minerals selenium and zinc are indispensable to the human immune system, because they are required to manufacture antioxidant enzymes, which protect the body from free-radical damage. Zinc, for example, is used to synthesize eighty different enzymes, including the body's most potent anti-aging enzyme, super oxide dismutase.
Other minerals essential for immune function include magnesium, potassium, manganese, sodium, copper and chromium.
Amino acids
Argine, when taken with synergistic cofactors such as vitamin B, stimulates the pituitary to secrete growth hormone, a vital immune regulator. Argine also enlarges the thymus gland (which produced T-cells), greatly enhances the body's healing powers and helps prevent cancer. Other immune-boosting amino acids include ornithine, cysteine, taurine, methionine, and glutathione.
Essential fatty acids
These nutrients, including omega-3 fish oils, oleic acid and caprylic acid, provide the best protection against arteriosclerosis and other forms of heart disease.
Since few people get adequate levels of these essential nutrients from their food (as clearly evidenced by the fact that heart disease now accounts for 53 per cent of all deaths in the UK), supplemental sources are required.
Fatty acids are also essential elements in white blood cells, antibodies, and brain cells.
Enzymes
Since modern diets consist primarily of cooked and processed foods, the body must divert much of its enzyme power to the stomach and duodenum for digestive duty, thereby sharply reducing the availability of enzymes for antioxidant activity and other immune functions.
When taken on an empty stomach, enzyme supplements go to work digesting microbes, pre-cancerous cells, toxins, pus, mucus, and other disease causing agents.
Lacto bacteria
Supplemental sources of lacto bacteria such as acidolpholis, bifidus, and fermented cabbage juice replenish the colonies of "friendly" bacteria in the intestinal tract. Lacto bacteria are the body's only natural defence against Candida and other yeast infections, which have powerful immunosuppressive properties.
They also facilitate rapid elimination of toxic digestive wastes and improve assimilation of essential nutrients from food.
Bibliography
Tatora and Grabowski (9th ed) Principles of anatomy and physiology. John Wiley & Sons: New York
Jones and Jones (1997) Advanced biology. Cambridge University Press: Cambridge
Elaine Marieb (5th ed) Principles of anatomy and physiology. Benjamin Cummings: New York
http://www.accessexcellence.org/AB/GG/antibodies.html
Lecture Notes.