Our Immune System
/The immune system is made up of specialized cells, proteins, tissues, and organs that work together to protect the body. This complex defense system identifies and destroys pathogenic viruses, fungi, bacteria, parasites and tumor cells. There are two levels of immune response.
INNATE IMMUNITY is the body’s first line of defense . This includes physical barriers such as the skin, mucous, cilia, protective bacteria, hair, tears, saliva, stomach acid, and the blood brain barrier. In addition to these protections we were born with, white blood cells attack and destroy pathogens that enter from the outside.
ADAPTIVE IMMUNITY develops as we age and are exposed to new viruses and bacteria. This acquired line of defense shifts into gear when pathogens penetrate the innate line of defense. Now, more specialized white blood cells (B and T lymphocytes) are mobilized to identify, tag and kill invaders more efficiently. These lymphocytes also develop a memory for the invader so they can identify them quickly in the future.
WHITE BLOOD CELLS (leucocytes)
WBC’s are the soldiers of the immune system. They identify, tag, engulf, ingest, burst, perforate or poison foreign organisms and cancer cells. They are also involved in allergic and inflammatory reactions as well as eliminating worn-out body cells. All five types of WBC’s originate in the bone marrow and as they mature, they enter the blood, thymus, organs and lymphatic tissues. They compose about 1% of blood volume, are larger than red blood cells, and fewer in number.
LYMPHATIC SYSTEM
When the heart pumps blood through the capillaries, the clear, nutrient-rich component of the blood (plasma) diffuses into the spaces surrounding body cells. The cells absorb what they need from the plasma, as well as release their waste products into this extracellular fluid. The lymphatic vessels then absorb a portion of the extracellular fluid and filter it through a series of nodes filled with white blood cells which destroy pathogens and cellular debris. At the end of the lymphatic circuit, the lymph fluid rejoins the cardiovascular system and the cycle starts again.
Lymph tissue is scattered through the body, with 60% to 70% embedded in the mucous membranes and tissues of the respiratory and digestive tract since this is where most pathogen enter the body. The spleen, thymus, appendix and tonsils are also part of the lymphatic system.
MORE ABOUT PROTECTIVE BARRIERS
The lung, colon, and skin provide physical barriers against most pathogens that enter the body from the external environment. The mucous membranes of the respiratory and digestive system trap infectious agents so they can be destroyed by the immune system. A variety of white blood cells, lymphatic tissues, and other anti-microbial molecules are sequestered within the lung and colon.
The skin eliminates toxins through sweating and shedding and is also home to numerous protective bacteria,
GOOD BACTERIA (microflora, probiotics)
Microscopic bacteria in the body outnumber our tissue cells by a factor of 10, with 100 trillion bacteria living in the digestive system alone. Approximately 85% are beneficial. The large intestine is host to more than 400 species. Colon bacteria weighs 2 to 5 pounds. Although most nutrients from our food are absorbed in the small intestine, the beneficial bacteria reside mostly in the large intestine and perform multiple functions:
break down the remains of undigested food to provide energy
produce vitamin K, biotin. folate, B6, B12, and niacin
stimulate lymphatic tissue embedded in the digestive tract
protect against pathogenic microbes
