The lymphatic system collects and returns interstitial fluid to the blood, absorbs fats from the digestive tract, and is a critical part of the immune system, housing lymphocytes that defend against pathogens.
T-cells mature in the thymus, where they are educated to recognize self and non-self cells. Bone marrow produces T-cell precursors, but maturation occurs in the thymus.
NK cells are part of the innate immune system and attack infected or cancerous cells without the need for prior exposure. B and T cells belong to the adaptive immune system, and plasma cells are antibody-secreting B cells.
The spleen filters the blood, removes old or damaged red blood cells, and provides an environment for immune cells to respond to blood-borne pathogens.
Antibodies are proteins secreted by activated B cells (plasma cells) that bind to specific antigens, neutralize pathogens, and mark them for destruction by other immune cells.
