The Lymphoid System

Vocabulary flashcards covering key concepts related to the lymphoid and immune systems, including function, structure, and key components.

Microbiome

Microorganisms that reside on and in the human body, some are beneficial while others have potential to be harmful.

Immune system

A cell population that inhabits all organs and defends the body from disease agents.

Lymphoid system

A network of organs and vessels that recovers fluid, inspects it for disease agents, and activates immune responses.

Lymphedema

Swelling due to interference in lymphatic drainage.

Lymph

Clear, colorless fluid similar to plasma but low in protein, which originates as tissue fluid taken up by lymphatic vessels.

Lymphatic vessels

Vessels that transport lymph and include lymphatic capillaries and larger vessels that have tunica interna, media, and externa.

Neutrophils

Antibacterial cells associated with the lymphoid system.

T lymphocytes (T cells)

Lymphocytes that mature in the thymus.

B lymphocytes (B cells)

Cells that, upon activation, proliferate and differentiate into plasma cells that produce antibodies.

Macrophages

Large phagocytic cells that are antigen-presenting cells (APCs), displaying antigens on their surface.

Thymus

An organ involved in T cell development, located between the sternum and aortic arch.

Lymph nodes

Bean-shaped structures that cleanse lymph and are sites of lymphocyte activation.

Spleen

The body's largest lymphoid organ, responsible for recycling RBCs and monitoring blood for foreign antigens.

Tonsils

Patches of lymphoid tissue located at the entrance to the pharynx that guard against ingested or inhaled pathogens.