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32 terms

07 Lymphatic System

USU Biol 2420, Summer 2012, Andy Anderson This includes some, but not all, of the information from the supplemental readings.
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Lymphatic system
This body system consists of vessels and organs that absorb excess interstitial fluid, absorb fats in the form of lipoproteins, and continually produce lymphocytes.
Lymphocytes
These cells are made in the bone marrow but continue to divide in the lymphatic system when stimulated by antigens.
Lymphatic vessels
These vessels form a one-way system of capillaries, vessels, and finally ducts.
Lymph
This is the name for the fluid inside lymphatic vessels. It consists of interstitial fluid, which is made up of water, solutes, and cellular wastes.
Lacteals
These are the lymphatic vessels in the villi of the small intestine that absorb chylomicrons.
Thoracic duct
This large, lymphatic duct returns collected lymph from below the thorax, from the left arm, and from the left side of the head and neck to the left subclavian vein.
Right lymphatic duct
This large, lymphatic duct returns collected lymph from the right side of the head and neck and the right arm to the right subclavian vein.
Compression by skeletal muscles
This is responsible for the movement of lymph through lymphatic vessels. Backflow is prevented by the presence of one-way valves.
Lymphatic organs
This is the general name for the organs associated with the lymphatic system. They can be primary or secondary.
Primary lymphatic organs
These lymphatic organs include the red bone marrow and thymus gland.
Secondary lymphatic organs
These lymphatic organs include the lymphatic nodules and the spleen.
Red bone marrow
This is what produces all types of blood cells. It is a primary lymphatic organ. In adults, it is found in the sternum, vertebrae, ribs, pelvic girdle, and proximal ends of the humerous and femur bones.
Thymus gland
This is the bilobed organ found in the thoracic cavity directly behind the sternum and in front of the trachea. It is a primary lymphatic organ. It produces thymosin and helps with the maturation of T cell lymphocytes. If any T cells are found to be self-reactive, then they die in the thymus and don't get released into the blood.
Thymosin
This is a hormone made by the thymus that is thought to help T cells mature.
Spleen
This secondary lymphatic organ is also the largest lymphatic organ. It is located in the upper left abdominal quadrant just below the diaphragm and posterior to the stomach. It has two regions: red pulp and white pulp.
Red pulp
This part of the spleen surrounds the venous sinuses that filter blood. Here, macrophages engulf pathogens and worn out erythrocytes.
Sickle-cell anemia
People with this disease sometimes have their spleen purposely removed in order to prolong the life of their abnormal RBCs.
White pulp
This part of the spleen contains mostly lymphocytes.
Outer capsule
This part of the spleen is relatively thin, and an infection or hard blow can cause the spleen to burst. If this happens, other organs like the liver can compensate, but the person will have a slightly higher risk of infection.
Lymph nodes
These structures occur at specific places along lymphatic vessels and filter lymph as it passes through. They are encapsulated and divided into compartments by connective tissue.
Inguinal lymph nodes
These lymph nodes are located in the groin region.
Axillary lymph nodes
These lymph nodes are located in the armpits.
Macrophages
These cells engulf pathogens and debris as lymph passes through lymph nodes.
Lymphocytes
These cell fight off infection and cancer cells in the lymph as it passes through the lymph nodes.
Lymphadenitis
This is the inflammation of lymph nodes.
Lymphatic nodules
These are masses of lymphatic tissue not surrounded by a capsule. The tonsils fall into this category.
Palatine tonsils
These lymphatic nodules are located at the back of the mouth on either side of the tongue below the soft palate.
Pharyngeal tonsils or adenoids
These lymphatic nodules are located in the upper portion of the pharynx.
Peyer's patches
There are many of these lymphatic nodules along the intestinal wall and in the appendix.
Radical mastectomy
This is a surgery used to treat breast cancer. In it, the afflicted breast, underlying muscles, and nearby axillary lymph nodes are removed. This can obstruct the normal flow of lymph in the nearby arm resulting in edema.
Elephantiasis
This disease is caused by the parasitic worm Wuchereria bancrofti that grows in and obstructs lymphatic vessels. This leads to localized edema.
Wuchereria bancrofti
This is the parasitic worm responsible for causing elephantiasis.