We are arguably the most complex organisms on this planet. Our bodies consist of a number of biological systems that carry out specific functions necessary for everyday living. Imagine trillions of cells, each with their own identity working together in a synergistic, cohesive manner for the safety and betterment of the entire being. The interplay among the chemical components of each cell is pretty dynamic yet organisms possess extraordinary attributes, properties that distinguish them from other collections of life forms, especially the ones that are detrimental to the function of the collective being.
Have you ever wondered why we get a fever or why we get a runny nose when we catch a cold or why our finger swells when we slam it against something? These are all signs of our body working efficiently to help us get over something. Lets take fever for example: fever or in other words a high temperature helps to combat infection by reducing the growth rate of microbes and also increase metabolic activity in body cells and activate heat shock proteins to strengthen the immune response. White blood cells release pro-inflammatory chemicals called cytokines which stimulate the anterior hypothalamus to produce prostaglandins, which lead to an increase in body temperature. More on Cytokines and Prostaglandins a bit latter. Fever is believed to be helpful in eliminating infections because most bacteria grow optimally at temperatures lower than normal body temperature.
So when we take medication to control fever we are pretty much working against our immune response. (fever may be beneficial up to a certain point, but beyond a tolerable limit it can cause damage to the body’s own enzymes, So it’s a balancing act!)
Allied Forces
We are constantly exposed to an incredible diversity of bacteria, viruses, parasites, toxins etc. Remarkably, we are often able to defend ourselves against these organisms, including the ones we have never even encountered before. So how does our body do this? We can thank our Immune System for this incredible defense system and the Lymphatic system which enables and facilitates the immune system. Our body calls upon the immune processes of the lymphatic system to protect itself from these invading microbes.
Lymphatic System
Imagine your body as an apartment building. You have water pipes running throughout the complex connecting to each and every house, carrying water around. People use this water for their day to day needs and the waste products are flushed out through the drainage system. The water pipes in this reference is your circulatory system, carrying all the nutrients, oxygen etc to all the cells in our body, one needs to function on a day to day basis. The drainage system is your lymphatic system getting rid of all the waste matter in form of Lymph. Along the way, the lymph travels through the lymph nodes, which are commonly found near the groin, armpits, neck, chest, and abdomen. Humans have about 500–600 lymph nodes throughout the body. The lymphatic vessels are punctuated at intervals by small masses of lymph tissue, called lymph nodes, that remove foreign materials such as infectious microorganisms from the lymph filtering through them.
The lymphatic system has its own tubes, pipes, connectors, reservoirs, and filters however
It lacks its own pumping organ like the Circulatory system.
However unlike the drainage system, Lymphatic system is not limited to only flushing out unwanted material. It is involved in so many other processes which makes it a key system in the human body. The lymphatic tissues play a vital role in circulation as well. The lymphatic system helps maintain fluid balance in the body by collecting excess fluid and depositing them in the bloodstream. Additionally, the transport of dietary lipids and fat-soluble vitamins absorbed in the gut uses this system. The immune system which is responsible for our Immunity is a key function of the lymphatic system. Possibly its most interesting functions are those related to its role in immunity, fighting biological invaders.
Unlike the cardiovascular/circulatory systems, the lymphatic system does not have a pump like the heart to shuttle this lymph around. It is forced through the vessels by the movements of the body, the contraction of skeletal muscles during body movements, and breathing (Yes, breathing plays a huge role in moving lymph around. kapaalabathi anyone?). One-way valves (semi-lunar valves) in lymphatic vessels keep the lymph moving towards the heart. Lymph flows from the lymphatic capillaries, through lymphatic vessels, and then is dumped into the circulatory system via the lymphatic ducts located at the junction of the jugular and subclavian veins in the neck.
Lymph is transported along the system of vessels by muscle contractions,
and valves prevent lymph from flowing backward.
Humans have about 500–600 lymph nodes throughout the body, which are commonly found near the groin, armpits, neck, chest, and abdomen. Almost 50-60% of these lymph nodes are located around the viscera. So doing certain yogic techniques like kapaalabathi, nauli are especially beneficial for moving this lymph around. In fact being physically active and incorporating any fitness regiment is very beneficial to keep the lymphatic system in top shape.
Immune System
The immune system is a sub system of the lymphatic system and they work together to stage an immune response. Cells of the immune system not only use lymphatic vessels to make their way from interstitial (within an organ/tissue) spaces back into the circulation, but they also use lymph nodes as major staging areas for the development of critical immune responses. The immune system is a collection of barriers, cells, and soluble proteins that interact and communicate with each other in extraordinarily complex ways. It gives us the ability to resist damage from foreign substances such as microorganisms; harmful chemicals, such as toxins released by microorganisms; and internal threats, such as cancer cells.
It is pretty much what is standing between us and a planet-full of invasive microorganisms.
Our body’s immune system works constantly to maintain a delicate balance. After all, it is life and death when it comes to certain immune responses. Our Immune systems should decide how strong the response should be. Too strong and it might cause more harm then good and not strong enough and the body can’t fight off the infection. So it’s a fine balancing game between these two extremes. So how do the immune cells know what is the right amount of response? The answer lies in coordinated decision making. Just like how we consult our close friends and family, to make better decisions, it turns out our cells consult their neighbours. When a particular site in our body is compromised, Immune cells count the number of their neighbours gathered at the compromised site to gauge the seriousness of the situation so they can decide on a good plan of action. They observe their surroundings to get a sense of their neighbours. This helps them fend off a threat without overreacting. Rather ingenious come to think of it and a lesson for all of us about positive cooperation for the betterment of the greater being!
When your immune system is functioning properly, most invaders don’t/can’t
stay for long. The immune system hunts them down, destroys them, and wraps
their cellular remains for elimination from the body.
We are are born germ-free and yet we have developed this impressive defense mechanism and surprisingly birth is the time when vitally important bacteria start to colonize the body including the gut, skin and lungs. During a natural birth, specific bacteria from the mother's gut are passed on to the baby and stimulate the baby's immune responses. There is quite a lot of evidence (Paul Wilmes et al, LCSB) to show why caesarean section babies are statistically more prone to develop allergies, chronic inflammatory diseases and metabolic diseases compared to babies born of natural birth. In fact it is the mother's gut bacteria that makes up much of the microbiome in the naturally delivered babies (Yan Shao et al, UCL).
So how exactly does our body defends itself? Part 2
Comments