What is the function of the immune system and how does it work?
Your immune system is your body's defense against infections and other harmful invaders (pathogens). It is essential for your health and survival. The main function of the immune system is to prevent or limit illness. One of the jobs of the immune system is to protect the host, you, from environmental agents (antigens) like viruses, germs, pathogens, fungi or chemicals, in an attempt to keep your body whole. When the body is invaded by bacteria, a virus, or parasites, an immune alarm goes off, setting off a chain reaction of cellular activity in the immune system to attack via the release of antibodies.
It is a very intricate process, a complex and extensive system. One of the amazing aspects of the immune system is that it is compensatory, meaning that when one part is weak or non-functional, typically another part can step in. The exact reason many people go day to day with an illness and yet can still “function”. That is not the optimal condition you want your immune system to be in, partially functioning. The goal is to have a fully functioning immune system for your best overall health.
This article will dig deep into your immune system and the importance of supporting a balanced immune response.
The immune system has numerous cell types that either circulate throughout the body or hang out in a particular tissue. Each cell type plays a unique role, with different ways of recognizing problems, communicating with other cells, and performing vital functions.
T-cells and B-cells, lymphocytes, are the special ops of your immune system. They both are critical to the body’s defense against infections and disease. The two types of T-cells are helper T-cells and killer T-cells. The helper cells stimulate B-cells to make antibodies which then help killer cells develop. The killer cells directly kill cells that are already infected by a foreign invader of some sort.
All immune cells come from precursors in the bone marrow and develop into mature cells through a series of changes that can occur in different parts of the body. Immune cells are in various places throughout the body.
Organs of the Immune System and Their Functions
Your immune system consists of your skin, bone marrow, bloodstream, thymus, lymphatic system, spleen, and mucosal tissue. White blood cells, leukocytes, are key players in your immune system. Found in your lymphoid organs, thymus, spleen, bone marrow, and lymph nodes, they circulate across your body through blood vessels and lymphatic vessels. Constantly on the prowl for pathogens and when the white blood cells notice one they multiply, along with their buddies, and overtake the intruder. When it comes to your skin, the harmless bacteria on your skin boost your immune cells to fight off disease-causing microbes.
Each part of the body has a specific and important job to carry out for the immune system to function.
Skin: The skin is usually the first line of defense against microbes. Skin cells produce and secrete important antimicrobial proteins, and immune cells can be found in specific layers of skin.
Bone marrow: The bone marrow contains stem cells that can develop into a variety of cell types. The common myeloid progenitor stem cell in the bone marrow is the precursor to innate immune cells—neutrophils, eosinophils, basophils, mast cells, monocytes, dendritic cells, and macrophages—that are important first-line responders to infection.
Bloodstream: Immune cells constantly circulate throughout the bloodstream, patrolling for problems. When blood tests are used to monitor white blood cells, another term for immune cells, a snapshot of the immune system is taken. If a cell type is either scarce or overabundant in the bloodstream, this may reflect a problem.
Thymus: T cells mature in the thymus, a small organ located in the upper chest.
Lymphatic system: The lymphatic system is a network of vessels and tissues composed of lymph, an extracellular fluid, and lymphoid organs, such as lymph nodes. The lymphatic system is a conduit for travel and communication between tissues and the bloodstream. Immune cells are carried through the lymphatic system and converge in lymph nodes, which are found throughout the body.
Lymph nodes are a communication hub where immune cells sample information brought in from the body. For instance, if adaptive immune cells in the lymph node recognize pieces of a microbe brought in from a distant area, they will activate, replicate, and leave the lymph node to circulate and address the pathogen.
Spleen: The spleen is an organ located behind the stomach. While it is not directly connected to the lymphatic system, it is important for processing information from the bloodstream. Immune cells are enriched in specific areas of the spleen, and upon recognizing blood-borne pathogens, they will activate and respond accordingly.
Mucosal tissue: Mucosal surfaces are prime entry points for pathogens, and specialized immune hubs are strategically located in mucosal tissues like the respiratory tract and gut. For instance, Peyer's patches are important areas in the small intestine where immune cells can access samples from the gastrointestinal tract.
Immune Cell Types Important to Your Immune System:
Granulocytes include basophils, eosinophils, and neutrophils. Basophils and eosinophils are important for host defense against parasites. They also are involved in allergic reactions. Neutrophils, the most numerous innate immune cell, monitoring for problems by circulating in the bloodstream. They can ingest bacteria, degrading them inside special compartments called vesicles.
Mast cells also are important for defense against parasites. Mast cells are found in tissues and can intercede allergic reactions by releasing inflammatory chemicals like histamine.
Monocytes, which develop into macrophages, also patrol and respond to problems. They are found in the bloodstream and tissues. They are named for their ability to ingest and deteriorate bacteria.
Macrophages also have important non-immune functions, such as recycling dead cells, like red blood cells, and clearing away cellular debris. These types of "housekeeping" functions occur without the activation of an immune response.
Dendritic cells (DC) are an important antigen-presenting cell (APC), and they also can develop from monocytes. Antigens are molecules from pathogens, host cells, and allergens that may be recognized by adaptive immune cells.
Natural killer cells (NK) are important for recognizing and killing virus-infected cells or tumor cells.
Adaptive Cells are your B cells and T cells. B cells have two major functions: they present antigens to T cells, and more importantly, they produce antibodies to neutralize infectious microbes. T cells have a variety of roles and they carry out multiple functions, including killing infected cells and initiating other immune cells into action.
Immune Response Process
The way the immune response tackles a problem goes like this. Antigens, any substance considered to be an intruder, prompt an immune response. Antigens can be viruses, bacteria, fungi, toxins, or other foreign materials. When your B cells spot an antigen, they release antibodies. Antibodies are part of the immunoglobulin family and are a type of protein that can catch antigens. Each antibody has a special function and can help to protect you from a specific antigen. This is the exact reason why you can't get chickenpox twice. Once your body creates an antibody it is stored in your body forever.
Types of Immunity:
- Innate immunity is the immunity you are born with that allows your body to fight pathogens until you develop adaptive immunity.
- Adaptive immunity is a form of immunity also called acquired immunity. It is a collection of antibodies that your body develops through being exposed to and fighting off pathogens during the span of your lifetime.
- Passive immunity is a form of immunity protection that a baby receives through the placenta and/or breast milk and lasts for a certain period to protect the body until it can defend itself.
As you have seen, our immune system is an amazing system choreographed by cells and organs all working to keep on top of unfavorable situations within the body. Sometimes things go haywire and the immune system fails for one reason or another. Why?
When complications arise the immune system can not function properly. From one end of the spectrum to the other for example, there is less pervasive pollen allergy, while genetic disorders are very extensive and wipe out the existence or function of an entire set of immune cells.
Immune System Problems
Some people are born with a weak immune system which is called primary immune deficiency. Some people get a disease that weakens the immune system which is called acquired immune deficiency. Yet others have an immune system that is too active. This may happen with an allergic reaction. Lastly, some have an immune system that turns against them which is called an autoimmune disease. Your immune system is very complex, hence there are various ways it can get out of balance and become compromised.
Immune deficiencies can arise from many different reasons including genetic defects from birth, obesity, age, alcoholism, malnutrition, and infections.
Autoimmunity is when your immune system attacks and destroys your cells mistaking them for pathogens or weak cells.
Hypersensitivity happens when your immune system overreacts and damages healthy cells.
Even if you do not have an immune system problem an unhealthy lifestyle, dietary choices, toxins, and stress can weaken the immune system and thus compromise your immune system response. This will make you more vulnerable to illness and make recovery more difficult.
Some things that weaken the immune system are poor nutrition, lack of oxygen, stress, antibiotics, and environmental toxins.
Immune system disorders
When your immune system becomes weak and does not work properly there is a high probability it will lead to an immune system disorder. Although there are over 100 types of autoimmune disorders, these are the most common ones:
- Immune deficiencies
- Autoimmune diseases Hashimoto's, Rheumatoid Arthritis, Lupus, Inflammatory bowel syndrome, and Type 1 Diabetes
- Psoriasis
- Sepsis
- Cancer
- Allergy-food sensitivities, sinusitis, asthma, eczema
Signs of a Weak Immune System
Chronic and frequent infections
Constant fatigue and low energy levels
Insomnia
Dark circles under the eyes
Depression
Joint pain
Anemia
Allergies
Mouth ulcers
Hair loss
Digestive problems
Injuries that are slow to heal
Chronic inflammation
*Did you know that inflammation is the beginning of many autoimmune disorders, chronic infections, and even cancer?! ~Dr. Nuzum
Supporting your immune system is important as well as having a strong and healthy body so that it can protect you from infections, illness, and disease. Especially during times of disease outbreaks or flu season, it is imperative to understand immune support strategies are critical for protecting your health.
Today, it is increasingly crucial to maintain strong and healthy immunity. It is known that when you work with the immune system and its indelible design, these disorders can correct in time as the internal environment of the body corrects. The immune system is the key, and the solution is to heal the immune system. Once the internal environment of the body is filthy, cluttered, and infested, the immune system will inevitably become dysfunctional.