Why the Lymphatic System Is Not Present in Certain Organs

¶ … network of lymph vessels and lymph nodes in the human body termed the lymphatic system that is an important component of the immune system (Lymph system, 2015). The lymphatic network collects waste materials, fluid, and pathogens such as bacteria and viruses in the body and carries lymph, a clear watery fluid that contains white blood cells called lymphocytes that help fight infections (Lymph system, 2015). To gain some additional insights into its purpose and operation, this paper provides an explanation concerning why the lymphatic system is not found in some parts of the body and describes what areas have no lymph or lymphatic vessels. A summary of the research and important findings concerning these issues are provided in the conclusion.

Review and Discussion

In 1652, the Danish physician Thomas Bartholin (1616 -- 1680) published a description of the human thoracic duct, noting that these lacteal vessels created another bodily circulatory system which he termed "the lymphatic system" (Windelspecht, 2002). Subsequently, a Swedish physician, Olof Rudbeck (1630 -- 1702), published an expanded description of the lymphatic system that proved that rather than flowing to the liver, lymphatic fluid is actually produced by the liver (Windelspecht, 2002).

Today, it is known that lymph nodes are located in the armpits, chest, abdomen, groin and neck and about one gallon of lymph is produced by the body each day, all of which circulates through the lymph nodes (Cavendish, 2004). It is also known that the lymphatic system is a second circulatory system that is comprised of both lymphatic vessels and lymphatic tissues and organs (The lymphatic system, 2015). A definition of these two components is provided below:

Lymphatic vessels are similar to and connect to blood vessels but unlike the blood vessels that transport blood that remains in the blood circulation, lymphatic vessels transport lymph which eventually enters the blood circulation;

Lymphoid tissues and organs are located in various body sites and abundantly populated by lymphocytes (Lymphatic system, 2015). .

Although lymphatic capillaries originate in the connective tissue of virtually all human organs, lymphatic vessels are not present in the human brain, bone marrow, spinal cord, eyeballs, cartilage, or inner ear; however, lymphocytes are present in some of these tissues (The lymphatic system, 2015). In this regard, Cavendish (2004) advises that, "While the organs of the chest and abdomen are richly supplied with lymphatic vessels, there are none in the brain or the spinal cord" (p. 1063). The reason for this absence is due to the fact that the lymphatic system is typically only present in tissues that have blood vessels and, subsequently there are no lymphatic vessels in the lens and cornea of the eye or in cartilage (Cavendish, 2004).