HUman Body | The Immune and Defense System
|The HUman body defense system is made up of entire organs, vessel systems, lymph vessels, individual cells and proteins. The inner and outer surfaces of the body are the first barriers against pathogens (germs/bacteria/virus). These surfaces include the skin and all mucous membranes, which form a protective barrier wall. |
What protects this barrier cell wall? At an early stage your body’s own antibacterial substances guard against pathogens from the environment. Enzymes found in your saliva, airways and tear duct fluids destroy cell wall bacteria.
Pathogens that are breathed in, get stuck to mucus in the bronchi, then moved out of the airways by hair-like structures called cilia.Most pathogens that enter the body with food or drink are usually stopped by your stomoch acid.
Normal flora, harmless bacteria that resides on the skin and mucous membranes in the body, also help to protect the body. Coughs and sneezing reflex can help remove pathogens.
What makes up the Immune and Defense System of the HUman Body?
The Immune System is made up of organs that control the production and maturation of certain defense cells, the lymphocytes (lymph system), bone marrow and the thymus, a gland situated above the heart and behind the breast bone, or so-called primary lymphoid organs.
Bone Marrow produces defense cells. Some of these defense cells, called T-lymphocytes (T stands for thymus), are differentiated in the thymus. That means that this is where T-lymphocytes develop into cells that are capable of recognizing non-self proteins, so-called antigens (antigens are toxins or foreign substances).
Bone marrow is a sponge-like tissue situated inside bones. Most defense cells are produced and then multiply here. They then migrate from the bone marrow into the bloodstream and reach other organs and tissues, where the defense cells mature and specialize. At birth, many bones contain red bone marrow, which actively builds defense cells. Over the course of your life, more and more red bone marrow turns into fat tissue. Adults only have red bone marrow in a few bones, (ribs, breast bone and pelvic).
The secondary lymphatic organs are the place where the defense cells do their actual work. These organs include the lymph nodes, the spleen, the tonsils and other specialized tissues in the mucous membranes, such as the bowel. In these places, the defense cells have constant contact with substances and pathogens.
Bacteria are micro-organisms that, unlike viruses, can exist on their own. Viruses, on the other hand, can only exist inside a living cell. Most bacteria is not harmful and some are actually beneficial. Bowel bacteria supports bowel health. However, in the urinary system, bacteria can cause an infection there.
The Lymphatic System is your life line. The lymph nodes and vessels are paramount for continually exchanging substances between blood and tissue in the body. Fluid constantly leaves the blood, and defense cells and proteins migrate into the surrounding tissue. Most of the fluid is later taken back into the blood vessels. The rest is removed by the drainage system of the lymph vessels (very important this function happens), which forms a fine net of thin-walled vessels in the body. The lymph nodes filter and clean the lymph fluid (lymph) on its way to the larger lymph vessels. The lymph finally travels to a vein called the superior vena cava (which is a large vein that carries deoxigenated blood into the heart), where it enters the blood stream.
The HUman body has two vena cava’s – the inferior vena cava that carries blood from the lower body and the superior vena cava, carrying blood from the head, arms, and upper body region.
Lymph nodes work like a biological filtration system. They contain different defense cells, which trap pathogens and activate the production of specific antibodies in the blood. If lymph nodes become swollen, painful or hard, it can be a sign of an active defense reaction of an infection or, in rare cases, a malignant change/s of the body’s own cells.
The Spleen is situated in the left upper abdomen, beneath the diaphragm. It has a variety of tasks in the defense system. In the unborn child, the spleen mainly produces blood and defense cells. After birth this organ is mainly responsible for removing blood cells and for specific defense functions. As part of the immune defense, functions of the spleen include the following:
It stores different defense cells that are released into the blood to get to organs, if needed: macrophages, also called scavenger cells, can attack non-self, substances and pathogens directly. T- lymphocytes inspect cell surfaces, help in controlling defense and can also directly destroy cells that have been recognized as non-self or as pathogens. B lymphocytes (a B-cell, white blood cell, functioning as an immune component of the adaptive immune system), secreting and producing antibodies, if needed.
It is responsible for removing red blood cells (erythrocytes). An erythrocyte is a red blood cell in the HUman body, without a nucleus. It contains hemoglobin pigment that imparts the red color to blood and transports oxygen and carbon dioxide to and from tissues. Spleen tissue is very soft. There is always plenty of blood flowing through spleen tissue. In heavy injuries, the spleen can rupture easily. If there is ever an injury to the spleen and bleeding cannot be stopped and must be removed, other defense organs take on most of the spleen’s tasks.
Blood Platelets (thrombocytes) are responsible for blood clotting, are stored and removed in the spleen. Platelets are tiny blood cells that help your body form clots (coagulation), to stop bleeding. If a blood vessel is damaged, chemical signals are sent to the platelets to attract more platelet friends. The additional platelets rush to the site of the damage to form a plug (clot) to repair injury, by piling onto the clot in a process called aggregation. The process of spreading across the surface of the damaged blood vessel is to stop the bleeding. This is called adhesion. When platelets arrive at site of injury, they grow sticky friend tentacles that help them adhere to one another, repairing damage.
Tonsils also belong to the defense system. Due to their special position at the throat and palate, their defense cells come into contact with pathogens and can activate the immune system immediately. Their tissue contains mainly lymphocytes (white blood cell, with round nucleus in the lymphatic system). In addition to the palatine tonsils on the right and left side, which are commonly just called tonsils, there are also the adenoids (in back of the naval cavity), above the roof of the throat, the lingual tonsil at the base of the tongue, and more lymphatic tissue on the sides of the throat. This lymphatic tissue can take on the function of the adenoids, if these have been removed.
The Lymphatic Tissue in Bowel plays a central role in defending the immune system of the body against pathogens. More than half of all cells that produce antibodies are found in the bowel wall, especially in the last part of the small bowel and in the appendix. These cells recognize pathogens and other non-self substances, mark and destroy them. They also store information on these non-self substances to be able to react faster the next time. The large bowel always contains bacteria that belongs to the body, the gut flora. Bacteria in the large bowel make it difficult for other pathogens to settle and enter the body. The immune system of the bowel tolerates the bacteria of the gut flora. Other parts of the body where pathogens may enter also contain lymphatic tissue in the mucous membranes. All this tissue together is also called mucosa-associated lymphoid tissue (MALT). As example, pathogens might enter the body through the airways or the urinary tract. Lymphatic tissue can be found in the bronchi and in the mucous membranes of the nose, the urinary bladder and the vagina with the defense cells being directly beneath the mucous membrane where they prevent bacteria and viruses from attaching.
The body truly is a divine machine of mastery. Honor thyself.