Your immune system protects you from outside invaders that can infect you and make you sick. Its main components are white blood cells, antibodies, the complement system, the lymphatic system, the spleen, the thymus, and bone marrow.
Lymphatic System: The lymphatic system is a network of delicate tubes throughout the body. It manages the fluid levels in the body, reacts to bacteria, deals with cancer cells, absorbs some of the fats from the intestines, and deals with cell products that otherwise would result in disease or disorders. This system is made up of lymph nodes that trap microbes and vessels that carry lymph, the colorless fluid that bathes your body’s tissues and contains infection-fighting white blood cells.
Bone Marrow: Bone marrow is the spongy tissue found inside your bones. It produces the red blood cells our bodies need to carry oxygen, the white blood cells we use to fight infection, and the platelets we need to help our blood clot.
Spleen: The spleen is a blood-filtering organ that removes microbes and destroys old or damaged red blood cells. It also makes disease-fighting components of the immune system.
Thymus: The thymus filters and monitors your blood content. It produces the white blood cells known as T lymphocytes (aka T cells). It produces fewer and fewer T cells as we age.
White Blood Cells
White blood cells are the key players in your immune system. They are made in your bone marrow and are part of the lymphatic system. They include lymphocytes (B cells, T cells, and natural killer cells) and many other types of immune cells.
White blood cells move through blood and tissue throughout your body, looking for foreign microbes such as bacteria, viruses, parasites, and fungi. When they find them, they attack them!
Antibodies help the body fight off invading microbes. They identify the microbes to attack by detecting antigens on the surface of the microbe. Once an invading microbe is identified and marked, white blood cells move in to destroy it.
What Is Inflammation?
Inflammation is actually the innate immune system’s immediate response to an infection. It’s the swelling, heat, sweating, pain, and increased blood flow that often surrounds the site of injury. More blood flow to the site of the injury means more white blood cells are available to come to the rescue!
So if you have a fever, that’s actually part of your body’s immune response! A rise in body temperature can help to kill some microbes. Fever also triggers the body’s repair process.
Your Two Lines of Defense
The Innate Immune System
You’re born with this rapid response system. It provides the majority of your body’s defense against foreign invaders from the environment, damage, or stress. This system is run by white blood cells (leukocytes) that eliminate pathogens by physically attacking them or engulfing them.
Prevent pathogen entry
White Blood Cells
Eliminate active pathogens
The Adaptive Immune System
You build this system as you are exposed to various pathogens day in and day out—and as you receive vaccinations against specific diseases. Your immune system keeps a record of every microbe it has ever defeated in types of white blood cells (B and T cells) known as memory cells. This means it can recognize and destroy the microbe quickly if it enters your body again, even before it can multiply and make you feel sick.
Some infections, like the flu and the common cold, have to be fought many times because so many different viruses can cause these illnesses. Catching a cold or the flu from one virus does not give you immunity against the others.
B Cell Immunity
T Cell Immunity
Eliminates infected host cells
Protein is a major component of immune health. Almost every component of the immune system needs protein to properly function. During times of stress, protein can aid immune function.
What Hurts, What Doesn’t?
Factors That Reduce Immunity
Factors That Improve Immunity