The lymphatic system is a part of the circulatory and immune systems that is “made up of a fluid called lymph which flows through lymphatic vessels, nodes, ducts and organs containing lymphatic tissue” (Board and Harlow 304). Proper functioning of this system is critical for human beings because it ensures decent dynamics of tissue fluid that is drained from the interstitial spaces. Before getting into the main lymphatic vessels, it gathers in pre-collector ones. Then fluid goes through several lymphatic tissue structures of the same group. They are known as lymph nodes or are called glands. Finally, vessels gather and create lymph trunks that pass fluid to ducts. All in all, this system is meant to control the presence and delivery of fluid and proteins to the blood as well as to absorb fat from the digestive system and transport it to venues. However, defending function in the framework of immunologic response can be even more critical.
It is significant to underline the role of nodes in this process because they are packed lymphocytes that generate immune bodies which allow the organism to resist infection. All in all, there are about 600 of them in a human body. They belong to different groups and have various sizes. Lymph nodes may be superficial or located deeply in the tissues. They can be axillary and inguinal. Some exist in groups that turn into modular patches. The most obvious and appropriate example tend to be the tonsils. Still, there are also those nodes that are not connected with others and exist independently, for example, the urogenital ones. The size of lymph nodes varies greatly. They can be from 1mm to 2sm 5mm in length and are put in a capsule of fibrous tissue of an appropriate size. All lymph nodes are divided into three parts: “the cortex, paracortex, and medulla” (Board and Harlow 304). The first one is packed with lymphocytes. They are also widely known as lymphatic nodules. Lymphocytes are those white blood cells that produce immune bodies and make the body fight infections and resist them. T-and B-lymphocytes or cells form the outer and the inner rim of the cortex respectively.
T-lymphocytes produce a protein, lymphotoxin, that belongs to “the tumor-necrosis factor family and can be produced as a secreted homotrimer, [Lymphotoxin-alpha] LTα” (Mebius 292). It is needed for normal lymph node, which means that those LTα that do not have lymph nodes are disrupted and do not allow the lymphatic system to function appropriately (Ettinger et al. 13102). The discussed homotrimer refers to the tumor necrosis factor family that is very inducible and secreted. It heterotrimers with LTβ to get to the cell surface. In this way, LTα receives an opportunity to respond various health issues. It deals with inflammation, immunostimulation, and antiviruses and affects the formation of the secondary lymphoid organs. In addition to that, it is involved in the process of apoptosis. Problems with LTα are tightly associated with poorly developed lymph nodes, which results in immunological issues (Alimzhanov et al. 9302).
Tightly connected with the lymphatic system is the immune system, which even has some similar functions. Its main task is to protect the body from different harmful agents that can affect one’s health condition adversely. The immune system, as well as the lymphatic one, includes lymph nodes, lymphocytes, and thymus that control the ability to resist diseases. In addition to that, it also deals with the spleen, which is full of white blood cells and ensures that the body has the appropriate amount of blood. Bone marrow and leukocytes have similar general functions.
The lymphatic system plays a critical immunological role. The vessels provide an opportunity to transfer the antigen-presenting cells of the immune system so that they can reach different secondary lymphoid organs, including lymph nodes (Stacker et al. 159). B-lymphocytes and T-lymphocytes maturation depends greatly on the nuclear factor-kappa B family through its influence on the development of hematopoietic cells that are integral components of the immune system. Even though lots of different cells are involved in immune responses, these lymphocytes are the main constituents of both innate and adaptive ones (Hayden, West and Ghosh 6758). It means that they are able to remember bacteria and viruses that caused infections previously and response to them appropriately next time. In this way, the constituents of the lymphatic system are significant for cell-mediated immunity, as they direct the immune system. Cytotoxic lymphocytes kill invading organisms with the help of special chemicals, allowing human beings to fight the infection and recover. The possibility to memorize those invaders that affected the organism negatively ensures that the immune system will be able to respond faster, which not only streamlines the process of recovery but also proves that the resistance and protection function of the lymphatic system can be constantly improved. In this framework, it is also critical to mention that T-lymphocytes control the response of the immune system for it not to damage normal cells (Gabrilovich and Srinivas 162).
Lymph nodes that are a part of the lymphatic system often turn out to be affected by the cancer metastasis, which is treated as the spread of cancer cells and their presence in new organs that were not initially affected. As a rule, it is seen in case of solid tumors. Professionals state that various cells in the lymph node can make it easier for the cancer cells to survive even though the immune system is supposed to fight them. However, they emphasize the fact that this creation of the environment that is positive for tumor cells has beneficial outcomes for the individual. In this way, they tend to home in lymphatic only and do not create metastasis in other organs due to the effect of interstitial fluid flow. As a result, lymph nodes function as a tumor drainage. Thus, it cannot be claimed for sure that the lymphatic node has only positive or only negative influence on the body’s resistance to cancer and metastasis.
The lymph nodes increase the possibility of having metastasis in them due to the fact that they drain the fluid from other body parts so that cancer cells follow it to the very nodes. In this way, the chances of having lymph nodes metastasis become higher, but the possibility of suffering other types of metastasis decreases. During the cancer surgery, professionals can remove those nodes that are affected, which can lead to life-long problems connected with problematic fluid circulation and extraction. However, in this way, the most significant organs can be protected, and one’s life can be saved. In addition to that, being yet not captured by metastasis, the lymph nodes can control fluid circulation in the body and avert tumors from developing at least for some time as they lack resources. Functioning as tumor drainage, the lymph node prevents systemic metastases that are peculiar for melanoma, fibro-sarcoma, gastric or colorectal carcinoma and breast cancer, etc. (Stacker et al. 161).
References
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Board, Jane, and Wendy Harlow. “Lymphoedema 1: Components and Function of the Lymphatic System.” British Journal of Nursing 11.5 (2002): 304. Print.
Ettinger, Rachel, Jeffrey Browning, Sara Michie, Willem van Ewijk and Hugh McDevitt. “Disrupted Splenic Architecture, but Normal Lymph Node Development in Mice Expressing a Soluble Lymphotoxin-Β Receptor–IgG1 Fusion Protein.” Proceedings of the National Academy of Sciences 93.23 (1996): 13102–13107. Print.
Gabrilovich, Dmitri, and Srinivas Nagaraj. “Myeloid-Derived Suppressor Cells as Regulators of the Immune System.” Nature Reviews Immunology 9.3 (2009): 162-174. Print.
Hayden, Matthew, Phillip West and Sankar Ghosh. “NF-kappaB and the Immune Response.” Oncogene 25.51 (2006): 6758-6780. Print.
Mebius, Reina. “Organogenesis of Lymphoid Tissues.” Nature Reviews Immunology 3.4 (2003): 292-303. Print.
Stacker, Steven, Steven Williams, Tara Karnezis, Ramin Shayan, Steohen Fox and Marc Achen. “Lymphangiogenesis and Lymphatic Vessel Remodelling in Cancer.” Nature Reviews Cancer 14.3 (2014): 159-172. Print.