Lymph Nodes: Locations and Functions

Lymph nodes, also known as lymph glands, are small, bean-shaped organs of the lymphatic system. The lymphatic system circulates the interstitial fluid called lymph to the body cells and tissues. It also collects waste substances from the bloodstream. Lymph contains white blood cells (WBCs) as its major component. It is more or less similar to the blood plasma. Lymph nodes, on the other hand, are made up of various types of cells and tissues, out of which WBCs and lymphoid tissues are more abundant. The size of lymph nodes in adults is smaller as compared to those in children between the age group 10-12. They play a major role in the normal functioning of the immune system.

Lymph Nodes: Locations

Lymph node is located in the lymphatic system, which is distributed throughout the body. It can be present independently or in groups. About 500-600 lymph nodes are present in the human body. Groups of lymph nodes are located in the neck, collarbone, under the arms (armpit) and groin. Lymph nodes are named according to their location in the body. Following is the list of major lymph nodes

• Cervical lymph nodes - Located in the head and neck portion. In total, they are six in number.
• Axillary lymph nodes - Present in the underarm area. They are divided into two types, namely, superficial and deep lymph nodes.
• Supraclavicular lymph nodes - Situated along the collarbones or clavicle.
• Femoral lymph nodes - Located in the upper thigh portion, along the femoral veins.
• Mesenteric lymph nodes - Distributed in the lower abdomen.
• Mediastinal lymph nodes - Present between the air sacs of the lungs.
• Inguinal lymph nodes - Located in the groin area. They may be supercritical or deep lymph nodes.

Lymph Nodes: Functions

As already mentioned, lymph nodes are essential organs of the immune system. They act as filters of disease causing agents like bacteria, viruses and other microorganisms. The foreign particles are then destroyed by the WBCs. To be more precise, the afferent vessels of the lymph nodes supply unfiltered body fluids to the lymph node for the filtration process. The fluids after filtration are collected by the efferent vessels and emptied to the cardiovascular system. According to medical studies, it is revealed that lymph nodes are the major sites for initiation of autoimmune responses.

Healthy lymph nodes retain their normal size (few millimeters to 2 cm). They are also not sensitive to touch. However, they turn swollen, inflamed and painful in certain health conditions. The enlargement of size is due to increased production of beta cells in the lymph nodes. Significant changes are observed in mild problem (cold) to life-threatening condition (cancer). Hence, the size of lymph nodes is very important to determine various medical conditions.

During the physical examination, the health care specialist examines for any swollen nodes in the major locations such as neck, armpit, collarbone and groin. Many a times, biopsy is conducted in order to diagnose a swollen or inflamed lymph node. The pathophysiology of breast cancer reveals that the disease spreads from the breast to the lymph nodes located in the armpit. Considering this, analyzing the presence of cancer in the axillary lymph nodes serves as a basic technique to diagnose the stage of breast cancer. The concerned physician may prescribe medications based on the current status of the lymph nodes.