Lymphatic System and Lymphoid Organs

Flashcards covering key terms and definitions related to the lymphatic system and lymphoid organs.

Lymphatic System

A network maintaining fluid balance and promoting immunity by returning fluids to blood.

Lymph

A fluid in lymphatic vessels that originates from interstitial fluid.

Lymph nodes

Organs that cleanse lymph and house immune cells.

Phagocytic cells

Cells that engulf and digest pathogens and debris.

Spleen

The largest lymphoid organ, involved in filtering blood and immune responses.

Thymus

An organ where T cells mature, especially active during childhood.

Lacteals

Specialized lymphatic capillaries in the small intestine that absorb fats.

Lymphatic capillaries

Blind-ended vessels that absorb interstitial fluid and become lymph.

Mechanisms of lymph transport

Includes contraction of skeletal muscle, pressure changes during breathing, and pulsation of arteries.

B cells

Lymphocytes that produce antibodies against antigens.

T cells

Lymphocytes that manage cell-mediated immunity and attack infected cells.

Macrophages

Cells that phagocytize foreign substances and help activate T cells.

Peyer's patches

Aggregated lymphoid follicles in the small intestine that protect against pathogens.

Cortex and Medulla in lymph nodes

Two histologically distinct regions, where lymphatic follicles and medullary cords are located.

Filtration in lymph nodes

The process by which lymph nodes filter out microorganisms and debris.

MALT (Mucosa-associated Lymphoid Tissue)

Lymphoid tissues located in mucous membranes protecting against pathogens.

Tonsils

Simplest lymphoid organs that form a protective ring around the pharynx.

Antigens

Foreign substances that trigger an immune response.

Splenic cords

Reticular tissue in the spleen containing lymphocytes and macrophages.

Hematopoiesis

The formation of blood cellular components, occurs in lymphoid tissues.

Thymosin

A hormone secreted by the thymus that promotes the development of T cells.