Protective antibodies are secreted by cells underlying the gastrointestinal lining. Furthermore, the stomach lining secretes hydrochloric acid that is strong enough to kill many microbes. There they encounter a variety of chemical substances that may prevent their growth. These substances include chemicals whose protective effects are incidental to their primary function in the body, chemicals whose principal function is to harm or destroy invaders, and chemicals produced by naturally occurring bacteria.
Some of the chemicals involved in normal body processes are not directly involved in defending the body against disease. Nevertheless, they do help repel invaders. For example, chemicals that inhibit the potentially damaging digestive enzymes released from body cells which have died in the natural course of events also can inhibit similar enzymes produced by bacteria, thereby limiting bacterial growth. Another substance that provides protection against microbes incidentally to its primary cellular role is the blood protein transferrin.
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The normal function of transferrin is to bind molecules of iron that are absorbed into the bloodstream through the gut and to deliver the iron to cells, which require the mineral to grow. The protective benefit transferrin confers results from the fact that bacteria, like cells, need free iron to grow. When bound to transferrin, however, iron is unavailable to the invading microbes, and their growth is stemmed.
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One group of such proteins is called complement because it works with other defense mechanisms of the body, complementing their efforts to eradicate invaders. Many microorganisms can activate complement in ways that do not involve specific immunity.
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Once activated, complement proteins work together to lyse, or break apart, harmful infectious organisms that do not have protective coats. Other microorganisms can evade these mechanisms but fall prey to scavenger cells, which engulf and destroy infectious agents, and to the mechanisms of the specific immune response. Complement cooperates with both nonspecific and specific defense systems. There are physical deterrents skin and nasal hairs , chemical deterrents enzymes found in perspiration and saliva , and inflammatory reactions initiated by immune cells.
These particular mechanisms are named appropriately because their responses are not specific to any particular pathogen. Think of these as a perimeter alarm system in a house. No matter who trips the motion detectors, the alarm will sound. White blood cells involved in the innate immune response include macrophages , dendritic cells , and granulocytes neutrophils, eosinophils, and basophils. These cells respond immediately to threats and are also involved in the activation of adaptive immune cells.
In cases where microorganisms get through the primary deterrents, there is a backup system called the adaptive immune system. This system is a specific defense mechanism in which immune cells respond to specific pathogens and also provide protective immunity.
Like innate immunity, adaptive immunity includes two components: a humoral immune response and a cell mediated immune response. This system uses white blood cells called B cells , which have the ability to recognize organisms that don't belong to the body. In other words, if this isn't your house, get out! Intruders are referred to as antigens. B cell lymphocytes produce antibodies that recognize and bind to a specific antigen to identify it as an invader that needs to be terminated.
The cell mediated immune response protects against foreign organisms that have managed to infect body cells. It also protects the body from itself by controlling cancerous cells. But sometimes it fails: A germ invades successfully and makes you sick. Is it possible to intervene in this process and boost your immune system? What if you improve your diet? Take certain vitamins or herbal preparations? Make other lifestyle changes in the hope of producing a near-perfect immune response?
The idea of boosting your immunity is enticing, but the ability to do so has proved elusive for several reasons. The immune system is precisely that — a system, not a single entity. To function well, it requires balance and harmony. There is still much that researchers don't know about the intricacies and interconnectedness of the immune response.
For now, there are no scientifically proven direct links between lifestyle and enhanced immune function. But that doesn't mean the effects of lifestyle on the immune system aren't intriguing and shouldn't be studied.
Researchers are exploring the effects of diet, exercise, age, psychological stress, and other factors on the immune response, both in animals and in humans. In the meantime, general healthy-living strategies are a good way to start giving your immune system the upper hand. Immunity in action.
A healthy immune system can defeat invading pathogens as shown above, where two bacteria that cause gonorrhea are no match for the large phagocyte, called a neutrophil, that engulfs and kills them see arrows. Your first line of defense is to choose a healthy lifestyle. Following general good-health guidelines is the single best step you can take toward naturally keeping your immune system strong and healthy. Every part of your body, including your immune system, functions better when protected from environmental assaults and bolstered by healthy-living strategies such as these:.
Don't smoke. Maintain a healthy weight. Take steps to avoid infection , such as washing your hands frequently and cooking meats thoroughly. Many products on store shelves claim to boost or support immunity.
But the concept of boosting immunity actually makes little sense scientifically. In fact, boosting the number of cells in your body — immune cells or others — is not necessarily a good thing.
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For example, athletes who engage in "blood doping" — pumping blood into their systems to boost their number of blood cells and enhance their performance — run the risk of strokes. Attempting to boost the cells of your immune system is especially complicated because there are so many different kinds of cells in the immune system that respond to so many different microbes in so many ways.
Which cells should you boost, and to what number? So far, scientists do not know the answer. What is known is that the body is continually generating immune cells. Certainly it produces many more lymphocytes than it can possibly use.
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The extra cells remove themselves through a natural process of cell death called apoptosis — some before they see any action, some after the battle is won. No one knows how many cells or what the best mix of cells the immune system needs to function at its optimum level. As we age, our immune response capability becomes reduced, which in turn contributes to more infections and more cancer.
As life expectancy in developed countries has increased, so too has the incidence of age-related conditions.
itlauto.com/wp-includes/monitor/1667-mini-camera-espion.php While some people age healthily, the conclusion of many studies is that, compared with younger people, the elderly are more likely to contract infectious diseases and, even more importantly, more likely to die from them. Respiratory infections, influenza, and particularly pneumonia are a leading cause of death in people over 65 worldwide. No one knows for sure why this happens, but some scientists observe that this increased risk correlates with a decrease in T cells, possibly from the thymus atrophying with age and producing fewer T cells to fight off infection.
Whether this decrease in thymus function explains the drop in T cells or whether other changes play a role is not fully understood.
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