The Immune response is elicited as a result of an injury or towards an invading pathogen. It initiates a physiological response which includes increase blood flow, which allows for the rapid removal of debris and pathogens, there is an increased permeability to aid in the migration of leucocytes to the site of injury, and fluids into the extravascular compartment which resulting in the dilution of toxins and pathogens. This is followed by coagulation to wall off the injured area. Also there is an increase in temperature which has an anti septic effect and also stimulates leucocyte activity. However while this response helps the body to alleviate the ongoing situation, for some conditions the response can become detrimental to health, that is, the inflammatory response is greater than that required creating more injury to the body than the original cause.
The Immune system consists of two aspects, the non-specific, which includes barriers to keep out pathogens, such as the skin and mucus membranes, which prevents dirt and pathogens from entering the body. These barriers also contain enzymes, for example lysosome, which potentially kills invading microbes. Coughing and the sneezing reflex can also help to expel unwanted pathogens. Some pathogens are swallowed and the gastric acid of the stomach helps to destroy any harmful microbes. The reproductive tract also has a mucus lining. Symbiotic bacteria contribute by creating an acidic environment and thereby acting as a deterrent, and also supporting the development of immune cells.
If a pathogen is able to breach these barriers then the body will react by producing an inflammatory response. This is not only activated by the invasion of an unwanted pathogen but other factors can also initiate such a response; for example, tissue damage due to an injury, and excess heat or cold. Internal trauma will also produce an inflammatory response, for example, damage to an artery wall.
The Innate Immune system is triggered when a pathogen enters the body. It will initiate the inflammatory response and the activation of the complement system. The compliment system promotes inflammation and the elimination of invading pathogens. Once triggered it sets off a chain reaction culminating in the death or opsonising of the microbe. The presence of this activity will attract macrophages and neutrophils into the area of infection. The compliment system plays a critical role in inflammation and defence against some pathogens. There may be an hereditary defect in the complement system leading to deficiencies of individual compliment components which can result in a variety of diseases.
The Adaptive or acquired Immune system provides another layer of defence when the invading microbes have proliferated in excess. This involves the activation of specialised cells. When these cells are activated they will not only respond to the present infection but to potential future occurrences of the same microbe. Unlike the innate system the adaptive system is specific in its response. The main cells involved are the B and T lymphocytes (white blood cells), B cells carry antibodies which helps to inactivate the microbe.
Types of Antibodies:
IgA Produced by the cells of the mucus membranes, saliva, perspiration and tears. Prevents antigens from attaching and crossing the epithelial membrane. It is present in the first breast milk produced which helps protect the infant from gastrointestinal infection.
IgE Found in cell membranes and if bound to an antigen it activates an inflammatory response and the release of Histamine Often found in excess in Allergies.
IgD. Mostly found on the surface of B cells and helps initiate the differentiation of B cells into plasma cells and memory B cells.
IgG largest and most common antibody. It attacks many different pathogens and crosses the placenta to protect the foetus. Also triggers the complement system.
IgM Produced in large quantities and is the primary response and potent activator of the compliment system
There are situations where the immune system attacks its own body's cells as in an autoimmune reaction. Also when the inflammatory response does not lead to a resolution as can be observed in conditions of chronic inflammation.
Many condition can be observed where an autoimmune response has preempted the condition, for example in Hashimoto's Thyroiditis, where the immune system attacks the thyroid gland ultimately destroying the thyroid tissue which leads to a reduction in the Thyroid hormone.
Chronic inflammation has been implicated in Diabetes, Obesity, Atherosclerosis, Hypertension, and other common conditions. Stress also stimulates inflammation. Stress can affect the immune system, in particular cortisol production which could eventually lead to low cortisol levels. The immunoregulatory hormone DHEA and testosterone are also implicated.
There are external factors that can contribute, towards inflammation, for example: food allergies, mercury toxicity, chronic exposure to mould, vitamin D deficiency, or lack of essential fatty acids, in particular Omega 3.
The Immune system can be affected in a number of ways;
- There may be an inborn deficiency.
- There is a lack of prerequisite nutrients weakening its ability to respond.
- It has become overwhelmed by some disease leading to immune deficiency.
- It may be overactive producing and allergic reaction.
- It may react against the cells of its own body as seen in Autoimmune disorders.
A healthy immune system is important in sustaining bodily health. Disruption could lead to variety of diseases which in itself will further weaken immune system health. The Immune and Endocrine systems are intimately related, disruption of one will lead to a dysfunction of the other. For example, excess or prolonged stress will reduce the body’s ability to fight off antigens thereby making it more susceptible to infections. Obesity and excess sugar and fats can lead to inflammation with a similar outcome. Therefore supporting the immune system is critical to good health. Dehydration can also be a stressor to the body so it is essential that the body is kept well hydrated.
Supporting the immune system involves more than just having sufficient nutrients but other factors also play an important role. For example, it is well know that depressions can lower the immune system’s ability to cope, and conversely a positive outlook can impact favourably on immune system health. Psychoimmunology is the study of the connections between the mind and the immune system.
Quality sleep is another significant factor as during sleep immune enhancing compounds are released and a great deal of repair is done to the body. Exercise can have a positive effect but it also requires sufficient rest, as excessive exercise can have a detrimental outcome. Nutritional deficiency is one of the main causes resulting in a depressed immune system.
Supporting the Immune System
- Address nutritional status, making sure that one is eating quality fruits and vegetables so that immune enhancing nutrients are consumed; they are antioxidants which are found in Vitamin C, and E, flavonoids, and carotenoids.
- Vitamin D deficiency has been linked to an increased susceptibility to developing an autoimmune condition, as well as an increased susceptibility to infection. Getting Vitamin D through more exposure to the sun will also positively enhance mood.
- It is always preferable to obtain nutrients from the diet rather than being reliant upon supplements, unless the diet is deficient in a particular nutrient. Vitamin C from food will offer a great deal more than just the one vitamin. This is particularly true of phytosterols, where they act more synergistically.
- Get sufficient quality sleep. It is estimated that the average adult requires 7 - 8 hours while teenagers 9 - 10, and children 11 - 12.
- Reducing Stress can make a significant impact, practicing meditation or mindfulness have proven to be useful ways of reducing stress.
- Exercise; moderate exercise has shown a positive relationship with health, as well helping to maintain bone density and muscle mass. However intensive training may have the opposite effect. Therefore it is important to build in periods of rest and quality sleep, as well as replenishing nutrient loss during exercise.
The Respiratory System and Skin
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