Humans and microbes form a symbiotic relationship with one another. Microbes live on all your body’s surfaces, including the gut, skin and mucous membranes.Your body contains up to ten times more bacterial cells than human ones, begging the question of whether the human body is more microbe or human!
The most prolific concentration of microbes exists in the gut, with over 10 trillion different organisms and 1,000 different species. These microbes play a key role in our innate immune defence system, helping to prevent disease as well as digesting food and nutrients. These gut microbes are your body’s key defence system against infections and disease. The body requires these microbes for survival, and the microbes thrive for survival on the body, herein the symbiosis as each one requires the other to thrive.
Bacteria can produce a new generation every 20-30 minutes and any change to the environment can alter the genetic development of the microbes, ensuring their continued survival.
This beneficial relationship is occurring constantly, however every so often harmful bacteria known as pathogens will break through the body’s innate defences. Pathogens include four different microorganisms including viruses, bacteria, funghi and parasites.
These pathogens can enter through inhalation in the respiratory tract, ingestion of contaminated food in the GI tract, via cuts or abrasions in the skin or through the mucous membranes (eyes, nose, mouth and throat). The respiratory system has its own self cleaning mechanism called the mucociliary escalator which acts to move particles and pathogens up and out the respiratory tract with the help of tiny hair like structures called cilia which line the surface of the airways.
Once a pathogen has entered the body, your immune cells spring into action. Neutrophils are the body’s fast-acting first responders; macrophages engulf pathogens and alert other immune cells; T cells coordinate immune response and attack infected cells; B cells produce antibodies and Natural Killer cells destroy infected host cells.