Lymphatic System

Lymph Nodes

Oval nodules that cleanse the lymph.

Lymph

Fluid in the lymph vessels.

Lymph Vessels (lymphatics)

Collect excess protein-containing interstitial fluid, transport pathogens to lymph nodes, and absorb fats from intestine to blood.

Hydrostatic Pressure

Outward pressure within lymphatic vessels.

Osmotic Colloid Pressure

Inward pressure that pulls fluid back into lymphatic vessels.

Lymphatic Capillaries

Blind-ended vessels that weave between tissue cells and blood capillaries, more permeable than blood capillaries.

Astrocytes

Cells that connect lymphatics in meninges and help drain extracellular fluid.

Lacteals

Specialized lymphatic capillaries in the small intestine that absorb and transport digested fat.

Cisterna Chyli

An enlarged sac that collects lymph from the lower body before it progresses to the thoracic duct.

Lymphangitis

Inflammation of lymphatic vessels, appearing as red streaks that are tender to touch.

Lymphedema

Insufficient return of lymph to blood, causing severe localized edema.

T Lymphocytes

Activated T cells that manage immune response and destroy infected cells; mature in the thymus.

B Lymphocytes

Produce plasma cells and antibodies to mark antigens for destruction; mature in lymph.

Macrophages

Phagocytize foreign substances and activate T cells.

Reticular Cells

Fibroblast-like cells that produce reticular fiber stroma in lymphoid organs and tissues.

Lymphoid Tissue

Diffuse lymphoid tissue found in various body organs, characterized by a loose arrangement of lymphoid cells.

Primary Lymphoid Organs

Organs where T and B cells mature; includes bone marrow and thymus.

Secondary Lymphoid Organs

Sites where mature lymphocytes first encounter antigens, including lymph nodes and the spleen.

Buboes

Infected lymph nodes that become inflamed and swollen, often associated with lymphadenopathy.

Spleen

Largest lymphoid organ, involved in lymphocyte proliferation, immune surveillance, and cleansing blood.

White Pulp

Area of the spleen where immune function occurs, composed mostly of lymphocytes.

Red Pulp

Area of the spleen where old blood cells and pathogens are destroyed, rich in RBCs and macrophages.

Mucosa-Associated Lymphoid Tissue (MALT)

Lymphoid tissues in mucous membranes throughout the body, including tonsils and Peyer's patches.

Peyer's Patches

Large clusters of lymphoid follicles in the distal portion of the small intestine, preventing bacteria from breaching the intestinal wall.

Thymus

Bilobed lymphoid organ where T lymphocytes mature; atrophies during puberty.

Blood Thymus Barrier

Protects immature T lymphocytes from premature activation by isolating them from antigens.