Lymph node

A lymph node ( Node lymphoideus, outdated Nodus lymphaticus, abbreviation Nl (singular ) / lymph. ( Plural) or Lymphonodus, abbreviation Ln., Plural Lnn. ) Is a " filter station " for the lymph ( tissue fluid ) and is part of the lymphatic system. Each lymph node is responsible for receiving and filtering the lymph of the body. This filtered complex is called tributäres area of the lymph nodes is the regional lymph nodes of the area.

Lymph nodes are part of the defense system (immune system) of an organism. They are found in all mammals, in a primitive form even in birds.

Size

Lymph nodes are approximately 5-10 mm in size and oval or irregularly shaped humans usually in the groin and the neck can also be up to 20 mm in size. If they are larger than 2 cm and assume a spherical shape, then they are activated and engaged in the defense of diseases. In animals, lymph nodes may merge into very large structures. So the knee wrinkles lymph nodes, for example, in cattle up to 11 cm long and 2 cm thick.

Anatomical structure

A lymph node is surrounded by a capsule, pull on the connective tissue septa ( trabeculae ) into the interior. The functional tissue inside is a lymphoreticular tissue. It consists of reticular cells and free cells (lymphocytes, antigen-presenting cells ). The reticular cells form a three-dimensional meshwork, whose cavities are called lymphatic sinus in lymph nodes.

The lymphoreticular tissue of the lymph node is divided into three areas where "mature" lymphocytes to exogenous proteins immunologically:

• In the cortex (cortex lymph nodes ), the lymphocytes are organized to Rindenfollikeln ( lymph ). They serve the proliferation and differentiation of B lymphocytes.
• In cord (medulla ) lymphoreticular tissue is stored in strands.
• Between cortex and medulla is a transition zone ( paracortex ) is the venue for the proliferation of T lymphocytes.

The lymph from the catchment area of the lymph node is called Primärlymphe. It occurs via afferent lymphatic vessels ( vasa lymphatica afferentia, singular Vas lymphaticum afferens ) through the capsule and flows through primarily the sinus system. The sinus wall cells and macrophages carry out non-specific phagocytosis. A small proportion of Primärlymphe infiltrates the lymphatic tissue and stimulates in the presence of antigens in the differentiation of lymphocytes. The resulting differentiated T, plasma and memory cells make their way into the lymph and the primary is thus to Sekundärlymphe. At the exit gate ( hilum or hilus ) the Sekundärlymphe a laxative lymphatic vessel ( vas lymphaticum efferens ) is derived.

In the lymph nodes of pigs, the ratios of cord, cortex, blood vessels, and thus the current path is reversed. The feeding artery passes through the hilum, the marrow is peripherally arranged the bark central and the efferent vessels leave the lymph node through the capsule.

The most important regions with lymph node

• Head and neck (behind the ear. Lnn retroauriculares, below the ear. präauriculares Lnn parotid ( Lnn. ), occipital: Lnn occipital, lower jaw. Lnn submandibular, chin. Lnn submental. ) in the neck ( Retropharyngeallymphknoten )
• Along the carotid arteries (neck lymph nodes)

Study opportunities

Superficially located lymph nodes can be keys with your fingers. For more detailed studies and the presentation of deep lymph nodes found ultrasound, computed tomography ( CT), magnetic resonance imaging ( MRI), and scintigraphy Lymphografie (see sentinel lymph node ) application.

The targeted tissue sample (biopsy ) from the lymph nodes or the surgical removal of a suspicious lymph node specimen can be obtained for histopathological examination.

Diseases

In diseases in the tributary area reach foreign cells and particles in the regional lymph nodes and there is a reaction. The flow direction in front of ( peripheral ) lying area must be regarded as a place of disease. Antigens trigger the proliferation of B and T lymphocytes. The lymph nodes swell as a result of ( lymphadenopathy, pathological lymph node swelling), and is usually only noticed by ( lymphadenitis or lymphoma). Activated lymph nodes have increased blood circulation in the ultrasound image an enlarged dark edge and are.

There are cancers that directly the lymph nodes ( Hodgkin's disease, non-Hodgkin's lymphoma).