Massage Therapy Journal Winter 2024

Winter 2024 • 41

AMTA Continuing Education

palpable lymph nodes should be referred to their physician so that illness and more serious conditions like a malignancy can be ruled out. Lymph nodes and node groups receive lymph fluid from specific body regions, known as tributary regions. Each tributary region is separated by a watershed. Direction of lymphatic flow changes at the watersheds, similar to the way water flows to the east and west on the continental divide. The median-sagittal watershed delineates the left and right side of the body. The transverse-horizontal watershed delineates the upper and lower trunk, and the clavicular/spine of the scapula watersheds delineate the head and neck from the trunk. Functions of Lymph Nodes and the Lymphatic System Lymph nodes filter harmful substances such as bacteria, viruses, toxins and dead cells. Lymph flows into a lymph node via afferent lymph collectors, and the flow slows down once it has reached the lymph node, enabling the immune fighting cells to recognize and destroy harmful pathogens. Storage of lymphocytes. Once lymphocytes have matured in either the thymus gland or the bone marrow, they are stored in the lymph nodes in preparation for the body’s immune response. Regulation of protein concentration in the lymph fluid. As the lymph fluid passes through the lymph node, excess water is reabsorbed back into the blood capillaries of the lymph node. Lymph fluid passes through several lymph nodes before reaching its destination, and has a different composition of water and protein by the time it reaches the thoracic duct. There is often a misconception around the nomenclature of these structures. They are often referred to as lymph glands. Glands secrete substances, such as sebaceous glands, which secrete oil onto the surface of the skin. Conversely, lymph nodes are not structured to secrete any substance. Many studies using laboratory animals indicate that once removed, nodes do not regenerate, resulting in compromised lymphatic

function that often leads to a condition known as lymphedema (abnormal accumulation of protein rich fluid in the interstitium). Additionally, lymph nodes that have been targeted with radiation cease to function effectively, which is why an individual who has received radiation to a group of lymph nodes can also be at risk of developing lymphedema. Functions of the Lymphatic System The lymphatic system removes fluid from the interstitium and transports it back to the cardiovascular system through the network of lymphatic vessels. One vital function of removing this fluid is the removal of the proteins in the interstitium. Without this mechanism of returning proteins back to the cardiovascular system, our bodies would not be able to synthesize enough proteins to survive. Proteins that remain in the interstitium promote the migration of other cells to the area, causing fibrosis of the dermal and subdermal tissues. Additionally, a collection of lymph vessels in the small intestines, known as lacteals, is responsible for the absorption of fat and fat soluble vitamins. When we digest fats, lymph fluid from the small intestines appears as a milky white fluid, known as chyle, which is then transported by the intestinal lymph trunk to the cysterna chyli, a small saclike structure that is located at the base of the thoracic duct. From here, the chylous fluid travels along the thoracic duct and enters the blood circulation at the left subclavian vein. Antigen presenting cells and T-and B-lymphocytes are circulated around the body by way of the lymphatic system, too. Lymph nodes are also a storage site for lymphocytes, which are then activated when an immune response is required. Lymphatic Vascular System: How Fluid Moves The lymph vascular system is a one-way drainage system that transports tissue fluid, cells and larger molecules within the fluid from the tissue spaces (interstitium) back to the cardiovascular system. The interstitium—also referred to as the extra

The lymphatic system removes fluid from the interstitium and transports it back to the cardiovascular system through the network of lymphatic vessels.

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