Lymph nodes

Small, bean-shaped structures that play a crucial role in the immune system.

Lymph nodes are specialized organs of the lymphatic system, functioning primarily as filters for lymph fluid. They are distributed throughout the body and contain immune cells that help in identifying and eliminating pathogens such as bacteria and viruses. Each lymph node is composed of lymphoid tissue, where immune responses are initiated, making them vital for maintaining the body's defense mechanisms.

Terminologia Anatomica

nodus-lymphaticus

System

Lymphatic system

Function

The primary function of lymph nodes is to act as filters for the lymphatic fluid that circulates throughout the body. As lymph fluid passes through these nodes, immune cells such as lymphocytes and macrophages examine it for signs of infection or foreign substances. When a pathogen is detected, lymph nodes mount an immune response, producing antibodies and activating additional immune cells to neutralize the threat. This process not only helps eliminate infections but also supports the continuous monitoring of the body for early signs of disease. In scenarios where the body is fighting an infection, lymph nodes may become swollen, indicating heightened activity as they work to protect the body from pathogens. Additionally, lymph nodes play a role in the transport of lymphatic fluid back to the bloodstream, thus maintaining fluid balance within the body's tissues.

Location

Lymph nodes are distributed throughout the body, with concentrations found in specific areas known as nodal regions. Major clusters include the cervical nodes in the neck, axillary nodes in the armpits, and inguinal nodes in the groin. Each region serves oncological and immunological functions specific to its location. For example, cervical nodes are involved in draining lymph from the head and neck, while axillary nodes filter lymph from the upper limbs and mammary glands. Situated along lymphatic vessels, these nodes are strategically placed to intercept pathogens as they travel through the lymphatic system towards the thoracic duct, where lymph ultimately enters the bloodstream. The arrangement allows for efficient immune surveillance, ensuring that any foreign particles are addressed promptly.

Did You Know?

Lymph nodes can number in the hundreds, with the average adult having between 600 to 700 lymph nodes in their body.
Superficial lymph nodes, located just beneath the skin, are often palpable when swollen, indicating an immune response.
Certain types of cancer can spread through the lymphatic system, leading to swollen lymph nodes as a sign of metastasis.
Lymph nodes also play a role in the production of immune cells; they are sites where B cells mature and become capable of producing antibodies.
Not all lymph nodes are the same; they can vary in size and function depending on their location and the specific immune challenges they face.