Glossary of the Lymphatic System

Transparent view of the body revealing circulatory system and organs

Immune system

The immune system is the body's defense system against infection and disease. See it in 3D!

System: Lymphatic

Region: All

Transparent view of the body revealing respiratory system and digestive system

Innate immunity

The innate immune response is a general response involving physical defenses, antimicrobial substances, fever, inflammation, and phagocytes that consume pathogens.

System: Lymphatic

Region: All

The nervous system and skeleton of the upper body

Adaptive immunity

The adaptive immune response is a targeted response in which B and T lymphocytes recognize and neutralize invading microbes in the lymphatic system and bloodstream.

System: Lymphatic

Region: All

Function: Activated B cells multiply to produce large numbers of clones, most of which become plasma cells. Plasma cells produce antibodies that recognize antigens on foreign microbes. The antibodies act as tags to identify the invaders. This is called an antibody-mediated response. T cells, activated by antigens presented by phagocytes, multiply then seek out and destroy infected cells.

The spleen located in the thorax

Spleen

Lien

The spleen is an organ whose functions mostly contribute to body defenses; it is considered part of the lymphatic system and is the largest lymphoid organ. See it in 3D!

System: Lymphatic

Region: Thorax

Function: The spleen’s varied functions include processing blood to remove dead or defective red blood cells and platelets; recycling iron from red blood cells; producing new red blood cells in the developing fetus; and serving as a site where populations of lymphocytes increase.

Pathologies: Acute lymphocytic leukemia, chronic lymphocytic leukemia, HIV/AIDS, Hodgkin Disease, infectious mononucleosis, lupus, lymphedema, lymphoma, multiple myeloma, myelodysplastic syndromes, Sjogren’s Syndrome

The thymus in the context of the skeleton and circulatory system

Thymus

Thymus

The thymus is an organ of the lymphatic system that functions in body defenses.

System: Lymphatic

Region: Thorax

Function: In the thymus, the lymphocytes called T cells—which form in red bone marrow—mature and become specialized. The thymus also produces hormones that are thought to regulate the development of T cells.

Pathologies: Acute lymphocytic leukemia, chronic lymphocytic leukemia, HIV/AIDS, Hodgkin Disease, infectious mononucleosis, lupus, lymphedema, lymphoma, multiple myeloma, myelodysplastic syndromes, Sjogren’s Syndrome

Tonsils viewed from an angle beneath the jaw in the context of the lymphatic system

Tonsils (Palatine tonsils)

Tonsillae palatinae

Each tonsil consists of lobes of lymphoid tissue aggregates that are covered with stratified squamous epithelium and lined by a continuation of the pharyngeal mucosa.

System: Lymphatic

Region: Head

Function: The palatine tonsils are two of the mucosa-associated lymphoid tissues (MALT), which protect the alimentary canal from pathogens.

Pathologies: Acute lymphocytic leukemia, chronic lymphocytic leukemia, HIV/AIDS, Hodgkin Disease, infectious mononucleosis, lupus, lymphedema, lymphoma, multiple myeloma, myelodysplastic syndromes, Sjogren’s Syndrome

The lymphatic system in the upper body

Lymph

Lymph derives from interstitial fluid that surrounds the cells of body tissues.

System: Lymphatic

Region: All

Function: Lymph is clear and colorless and contains white blood cells. The white blood cells can destroy pathogens and remove some unwanted substances from the interstitial fluid as it flows toward lymphatic tissues and lymph nodes.

Lymph nodes located in the neck and shoulders

Lymph node

Lymph nodes are capsules of tissue that filter lymph and contain lymphocytes that destroy pathogens. See it in 3D!

System: Lymphatic

Region: All

Function: The lymph nodes and lymphatic organs provide the key functional sites of the lymphatic system.

Pathologies: Acute lymphocytic leukemia, chronic lymphocytic leukemia, HIV/AIDS, Hodgkin Disease, infectious mononucleosis, lupus, lymphedema, lymphoma, multiple myeloma, myelodysplastic syndromes, Sjogren’s Syndrome

The human skeleton from the neck up overlayed with lymphatic system and lymphatic vessels

Lymphatic vessel

Lymph circulates throughout the body. It begins as interstitial fluid between cells and filters into lymphatic capillaries, flowing into larger vessels and trunks, and eventually returning to venous blood.

System: Lymphatic

Region: All

Function: Lymphatic vessels and ducts provide the complex transportation network of the lymphatic system.

Pathologies: Acute lymphocytic leukemia, chronic lymphocytic leukemia, HIV/AIDS, Hodgkin Disease, infectious mononucleosis, lupus, lymphedema, lymphoma, multiple myeloma, myelodysplastic syndromes, Sjogren’s Syndrome

Lymphatic ducts found in the torso viewed from the side

Lymphatic duct

Lymph empties into the bloodstream from the thoracic duct and right lymphatic duct, at the junction between the subclavian and internal jugular veins.

System: Lymphatic

Region: Thorax

Function: Lymphatic vessels and ducts provide the complex transportation network of the lymphatic system.

Pathologies: Acute lymphocytic leukemia, chronic lymphocytic leukemia, HIV/AIDS, Hodgkin Disease, infectious mononucleosis, lupus, lymphedema, lymphoma, multiple myeloma, myelodysplastic syndromes, Sjogren’s Syndrome

Cross section of a vein showing various immune cells such as a whtie blood cell

White blood cell

White blood cells, or leukocytes, are the component of blood that defends the body against disease. See it in 3D!

System: Lymphatic, Circulatory

Region: All

Lymphocyte

Lymphocyte

Lymphocytes, the second most common leukocytes, move mostly through lymphatic tissue and briefly through the bloodstream. See it in 3D!

System: Lymphatic

Region: All

B cell

B cell

B cells develop and mature in red bone marrow before becoming active in the spleen, lymph nodes, and bloodstream.

System: Lymphatic

Region: All

Function: They produce antibodies—substances that recognize the antigens on foreign microbes and act as tags that identify the invaders.

T cell

T cell

T cells develop in red bone marrow and mature in the thymus before becoming active in the spleen, lymph nodes, and bloodstream.

System: Lymphatic

Region: All

Function: Once activated by antigens—substances on foreign microbes—they seek out and destroy infected cells.

Natural killer cell

Natural killer cell

Natural killer cells attack and destroy foreign microbes.

System: Lymphatic

Region: All

Monocyte

Monocyte

Monocytes develop into macrophages and remove debris after an infection.

System: Lymphatic

Region: All

A phagocyte consuming a microorganism

Phagocyte

When bacteria or other pathogens are present in the body, certain white blood cells categorized as phagocytes consume the microorganisms to protect the body from infection.

System: Lymphatic

Region: All

Function: The process begins when chemicals from a pathogen, or damaged tissue, attract a phagocyte. The phagocyte binds to the microbe, envelopes it, and then eats it. Enzymes within the phagocyte kill and digest the pathogen. This action is called phagocytosis.