Lymphatic System and Lymphoid Organs and Tissues

Vocabulary flashcards for the Lymphatic System and Lymphoid Organs and Tissues lecture.

Lymphatic System

Network of lymphatic vessels (lymphatics), lymph fluid in vessels, and lymph nodes: cleanse lymph

Lymph

Fluid in lymphatic vessels.

Lymph Nodes

Cleanse lymph, provide structural basis of immune system by housing phagocytic cells and lymphocytes

Lymphatic Vessels (Lymphatics)

Elaborate network of drainage vessels that return interstitial fluid and leaked plasma proteins back to blood

Lymph

Fluid that enters lymphatics

Lymphatic Capillaries

Blind-ended vessels that weave between tissue cells and blood capillaries; absent from bones, teeth, and bone marrow

Lacteals

Specialized lymph capillaries present in intestinal mucosa that absorb digested fat and deliver fatty lymph (chyle) to the blood

Collecting Lymphatic Vessels

Lymph capillaries drain into increasingly larger vessels called

Lymphatic Trunks

Formed by union of largest collecting vessels, drain large areas of body

Right Lymphatic Duct

Drains right upper arm and right side of head and thorax

Thoracic Duct

Drains rest of body

Cisterna Chyli

Enlarged sac at the start of the thoracic duct

Lymphedema

Severe localized edema caused by anything that prevents normal return of lymph to blood

Lymphoid Cells

Immune system cells found in lymphoid tissue

Lymphocytes

Cells of the adaptive immune system; mature into T cells or B cells

Macrophages

Phagocytize foreign substances and help activate T cells

Dendritic Cells

Capture antigens and deliver them to lymph nodes; also help activate T cells

Reticular Cells

Produce reticular fibers called stroma in lymphoid organs

Stroma

Network-like support that acts as scaffolding for immune cells

Lymphoid Tissue

Houses and provides proliferation sites for lymphocytes and offers surveillance vantage points for lymphocytes and macrophages as they filter through lymph

Diffuse Lymphoid Tissue

Loose arrangement of lymphoid cells and some reticular fibers; found in virtually every body organ

Lymphoid Follicles (Nodules)

Solid, spherical bodies consisting of tightly packed lymphoid cells and reticular fibers; contain germinal centers of proliferating B cells

Primary Lymphoid Organs

Areas where T and B cells mature—red bone marrow and thymus

Secondary Lymphoid Organs

Areas where mature lymphocytes first encounter their antigen and become activated; nodes, spleen, MALT

Lymph Nodes

Principal secondary lymphoid organs of body; act as lymph filters and activate immune system

Buboes

Inflamed, swollen, tender lymph nodes that result when nodes are overwhelmed by what they are trying to destroy

Spleen

Blood-rich organ about size of fist, located in left side of abdominal cavity, just below stomach; cleanses blood and provides site for lymphocyte proliferation

White Pulp

Site where immune function occurs in the spleen; contains mostly lymphocytes on reticular fibers

Red Pulp

Site where old blood cells and bloodborne pathogens are destroyed in the spleen; rich in RBCs and macrophages

Splenectomy

Surgical removal of ruptured spleen

Mucosa-Associated Lymphoid Tissue (MALT)

Lymphoid tissues in mucous membranes throughout body; protects from pathogens trying to enter body

Tonsils

Simplest lymphoid organs; form ring of lymphatic tissue around pharynx

Peyer’s Patches

Clusters of lymphoid follicles in wall of distal portion of small intestine; destroy bacteria and generate memory lymphocytes

Appendix

Offshoot of first part of large intestine; contains a large number of lymphoid follicles; destroy bacteria and generate memory lymphocytes

Thymus

Bilobed lymphoid organ found in inferior neck; functions as lymphoid organ where T cells mature

Regulatory T Cells

Type of T cell that helps to prevent autoimmunity