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Encyclopedia > Lymph node
Lymph node
Structure of the lymph node.1. Efferent lymphatic vessel 2. Sinus 3. Nodule 4. Capsule 5. Medulla 6. Valve to prevent backflow 7. Afferent lymphatic vessel.
Latin nodus lymphoideus
Gray's subject #175 688
MeSH Lymph+nodes
Dorlands/Elsevier n_09/12576213

Lymph nodes are components of the lymphatic system. They are sometimes informally called lymph glands but, as they do not secrete substances, such terminology is not accurate. They are found throughout the body. Lymph node Afferent lymphatic vessel Sinus Nodule Capsule Hilum Valve to prevent backflow Efferent lymphatic vessel [1] File links The following pages link to this file: Lymph node Categories: United States government images ... For other uses, see Latin (disambiguation). ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... Elseviers logo. ... The human lymphatic system The lymphatic system is a complex network of lymphoid organs, lymph nodes, lymph ducts, lymphatic tissues, lymph capillaries and lymph vessels that produce and transport lymph fluid from tissues to the circulatory system. ... Human submaxillary gland. ...


Lymph nodes are filters or traps for foreign particles and contain white blood cells.

Contents

Function

Lymph nodes act as filters, with an internal honeycomb of reticular connective tissue filled with lymphocytes that collect and destroy bacteria and viruses. When the body is fighting an infection, lymphocytes multiply rapidly and produce a characteristic swelling of the lymph nodes. Reticular connective tissue are a network of reticular fibers (fine collagen) that form a soft skeleton (stroma) to support the lymphoid organs (lymph nodes, bone marrow, and spleen. ... A scanning electron microscope (SEM) image of a single human lymphocyte. ...


Structure

The lymph node is surrounded by a fibrous capsule, and inside the lymph node the fibrous capsule extends to form trabeculae. Thin reticular fibers form a supporting meshwork inside the node. The word capsule (from the Latin capsula, a small box), has many similar meanings in English: In botany, a capsule is a type of dry fruit as in the poppy, iris, foxglove, etc. ... The word capsule (from the Latin capsula, a small box), has many similar meanings in English: In botany, a capsule is a type of dry fruit as in the poppy, iris, foxglove, etc. ... A trabecula (plural trabeculae) is a small, often microscopic, tissue element in the form of a small beam, strut or rod, generally having a mechanical function, and usually but not necessarily composed of dense collagenous tissue. ...


The concave side of the lymph node is called the hilum. The artery and vein attach at the hilum and allows blood to enter and leave the organ, respectively. Anatomic nomenclature for a depression or pit at the part of an organ where vessels and nerves enter. ... Section of an artery For other uses, see Artery (disambiguation). ... In the circulatory system, a vein is a blood vessel that carries blood toward the heart. ...


The parenchyma of the lymph node is divided into an outer cortex and an inner medulla. Parenchyma is a term used to describe a bulk of a substance. ... In anatomy and zoology the cortex is the outermost (or superficial) layer of an organ. ... Medulla in general means the inner part, and derives from the Latin word for marrow. In medicine it is contrasted to the cortex. ...


Cortex

In the cortex, the subcapsular sinus drains to cortical sinusoids. The pulp of the lymph gland does not, completely fill the spaces, but leaves, between its outer margin and the enclosing trabeculae, a channel or space of uniform width throughout. ...


The outer cortex and inner cortex have very different properties:

Location Name/description Predominant lymphocyte Has nodules?
outer cortex nodular cortex B cells yes
deep cortex juxtamedullary cortex or paracortex T cells no

The cortex is absent at the hilum. B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response). ... There are very few or no other articles that link to this one. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... Anatomic nomenclature for a depression or pit at the part of an organ where vessels and nerves enter. ...


It is made out of the fluid from the blood called plasma.


Medulla

There are two named structures in the medulla:

  • The medullary cords are cords of lymphatic tissue, and include plasma cells and T cells
  • The medullary sinuses (or sinusoids) are vessel-like spaces separating the medullary cords. Lymph flows to the medullary sinuses from cortical sinuses, and into efferent lymphatic vessels. Medullary sinuses contain histiocytes (immobile macrophages) and reticular cells.

Plasma cells (also called plasma B cells or plasmocytes) are cells of the immune system that secrete large amounts of antibodies. ... T cells are a subset of lymphocytes that play a large role in the immune response. ... The efferent lymphatic vessel commences from the lymph sinuses of the medullary portion of the lymph nodes. ... A Histiocyte is a cell that is part of the human immune system. ... A reticular cell produces reticular fibers and surrounds the fibers with its cytoplasm, which isolates the fiber from other components of the tissues or cells. ...

Shape and size

Human lymph nodes are bean-shaped and range in size from a few millimeters to about 1-2 cm in their normal state. They may become enlarged due to a tumor or infection. White blood cells are located within honeycomb structures of the lymph nodes. Lymph nodes are enlarged when the body is infected due to enhanced production of some cells and division of activated T and B cells. In some cases they may feel enlarged due to past infections; although one may be healthy, one may still feel them residually enlarged. White Blood Cells is also the name of a White Stripes album. ...


Lymphatic circulation

Lymph circulates to the lymph node via afferent lymphatic vessels and drains into the node just beneath the capsule in a space called the subcapsular sinus. The subcapsular sinus drains into trabecular sinuses and finally into medullary sinuses. The sinus space is criss-crossed by the pseudopods of macrophages which act to trap foreign particles and filter the lymph. The medullary sinuses converge at the hilum and lymph then leaves the lymph node via the efferent lymphatic vessel. In mammals including humans, the lymphatic vessels (or lymphatics) are a network of thin tubes that branch, like blood vessels, into tissues throughout the body. ... The afferent lymphatic vessels enter at all parts of the periphery of the gland, and after branching and forming a dense plexus in the substance of the capsule, open into the lymph sinuses of the cortical part. ... The pulp of the lymph gland does not, completely fill the spaces, but leaves, between its outer margin and the enclosing trabeculae, a channel or space of uniform width throughout. ... Pseudopods or pseudopodia (false feet) are temporary projections of eukaryotic cells. ... A macrophage of a mouse stretching its arms to engulf two particles, possibly pathogens Macrophages (Greek: big eaters, from makros large + phagein eat) are cells within the tissues that originate from specific white blood cells called monocytes. ... The efferent lymphatic vessel commences from the lymph sinuses of the medullary portion of the lymph nodes. ...


Lymphocytes, both B cells and T cells, constantly circulate through the lymph nodes. They enter the lymph node via the bloodstream and cross the wall of blood vessels by the process of diapedesis. A lymphocyte is a type of white blood cell involved in the human bodys immune system. ... B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response). ... T cells are a subset of lymphocytes that play a large role in the immune response. ... Diapedesis is the movement of leukocytes across the endothelial lining of blood vessels to interstitial fluid (IF). ...

  • The B cells migrate to the nodular cortex and medulla.
  • The T cells migrate to the deep cortex.

When a lymphocyte recognizes an antigen, B cells become activated and migrate to germinal centers (by definition, a "secondary nodule" has a germinal center, while a "primary nodule" does not). When antibody-producing plasma cells are formed, they migrate to the medullary cords. Stimulation of the lymphocytes by antigens can accelerate the migration process to about 10 times normal, resulting in characteristic swelling of the lymph nodes. An antigen or immunogen is a molecule that stimulates an immune response. ... Germinal centers (GC) are an important part of the humoral immune response. ...


The spleen and tonsils are large lymphoid organs that serve similar functions to lymph nodes, though the spleen filters blood cells rather than bacteria or viruses. The spleen is an organ located in the abdomen, where it functions in the destruction of old red blood cells and holding a reservoir of blood. ... This article or section contains too much jargon and may need simplification or further explanation. ...


Distribution

Regional lymph tissue

Humans have approximately 500-600 lymph nodes distributed throughout the body, with clusters found in the underarms, groin, neck, chest, and abdomen. Image File history File linksMetadata Illu_lympha_man. ... Image File history File linksMetadata Illu_lympha_man. ...


Lymph nodes of the human head and neck

  • Tonsillar: (sub mandibular) These nodes are located just below the angle of the mandible. They drain the tonsillar and posterior pharyngeal regions.
  • Sub-mandibular: These nodes run along the underside of the jaw on either side. They drain the structures in the floor of the mouth.
  • Sub-mental: These nodes are just below the chin. They drain the teeth and intra-oral cavity.

Cervical lymph nodes are lymph nodes found in the neck. ... In human anatomy, the sternocleidomastoid muscles are muscles in the neck that acts to flex and rotate the head. ... For other uses, see Throat (disambiguation). ... The pharynx (plural: pharynges) is the part of the neck and throat situated immediately posterior to the mouth and nasal cavity, and cranial, or superior, to the esophagus, larynx, and trachea. ... This article or section contains too much jargon and may need simplification or further explanation. ... The thyroid gland and its relations In anatomy, the thyroid (IPA θaɪɹoɪd) is an endocrine gland. ... Trapezius In human anatomy, the trapezius is a large superficial muscle on a persons back. ... The mastoid portion of the temporal bone (or mastoid process) forms the posterior part of the temporal bone. ... Collarbone and collar bone redirect here. ... Upper respiratory tract infection, also popularly known as either the acronym URTI or URI, is the disease characterised by an acute infection which involves the upper respiratory tract: nose, sinuses, pharynx, or larynx. ... The mandible (from Latin mandibÅ­la, jawbone) or inferior maxillary bone is, together with the maxilla, the largest and strongest bone of the face. ... Supraclavicular lymph nodes are lymph nodes found superior to the clavicle, palpable in the supraclavicular fossa. ... Collarbone and collar bone redirect here. ... The sternum (from Greek στέρνον, sternon, chest) or breastbone is a long, flat bone located in the center of the thorax (chest). ... The thoracic cavity is the chamber of the human body (and other animal bodies) that is enclosed by the ribcage and the diaphragm. ... In medicine (oncology), Virchows node is an enlarged, hard, left supraclavicular lymph node which can contain metastasis of visceral malignancy. ... In human anatomy, the thoracic duct is an important part of the lymphatic system — it is the largest lymphatic vessel in the body. ... For the musical composition, see Metastasis (Xenakis composition). ...

Lymph nodes of the arm

These drain the whole of the arm, and are divided into two groups, superficial and deep. The superficial nodes are supplied by lymphatics which are present throughout the arm, but are particularly rich on the palm and flexor aspects of the digits.

  • Deep lymph glands of the arm: These comprise the axillary glands, which are 20-30 individual glands and can be subdivided into:
    • lateral glands
    • anterior or pectoral glands
    • posterior or subscapular glands
    • central or intermediate glands
    • medial or subclavicular glands

The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ... In human anatomy, the basilic vein is a superficial vein of the upper limb. ... Dermatomes Dermatomic area (also known as a dermatome) is an area of skin that is supplied by a single pair of dorsal roots. ... Location The clavicular head of the pectoralis major takes its origin from the anterior surface of the medial half of the clavicle. ... Deltoid can refer to: The deltoid muscle, a muscle in the shoulder A deltoid curve, a three-sided hypocycloid A type of quadrilateral A leaf shape The deltoid tuberosity, a part of the humerus Delta, an article with related definitions. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... Collarbone and collar bone redirect here. ... The Axillary lymph nodes are of large size, vary from twenty to thirty in number, and may be arranged in the following groups: brachial lymph nodes (or lateral) pectoral axillary lymph nodes (or anterior) subscapular axillary lymph nodes (or posterior) central lymph nodes apical lymph nodes (or medial or subclavicular...

Lower limbs

The superficial inguinal lymph nodes form a chain immediately below the inguinal ligament. ... The deep inguinal lymph nodes are located medial to the femoral vein and under the cribriform fascia. ...

Additional images

See also

Adenitis is a general term for an inflammation of a gland or lymph node. ... Lymphadenectomy consists on the surgical removal of one or more groups of lymph nodes. ...

External links


  Results from FactBites:
 
Biopsy (0 words)
Sentinel lymph node biopsy is a procedure in which one sentinel lymph node (sometimes more than one and sometimes just a portion of one) is removed and examined under a microscope to determine whether cancer cells are present.
Lymph node biopsy can be done surgically (open biopsy) or by needle, depending on the location of the area being tested and the reason it is being tested.
For a regional lymph node dissection, some of the lymph nodes in the tumor area are removed; for a radical lymph node dissection, most or all of the lymph nodes in the tumor area are removed.
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