The immune system of a multicellular organism has several functionslike excretion and reproduction. It acts primarily as a defense against foreign pathogens (such as viruses, bacteria, parasites), some poisons, as well as cancer. It also functions in the return of extracellular fluid to the blood, and the formation of white blood cells.

Animal anatomy | Immunology | Organ systems

Kategori:Immunforsvar | Catégorie:Système immunitaire | 분류:면역 기관 | Kategorija:Imunski sistem | Kategori:Bağışıklık sistemi | Thể loại:Hệ miễn dịch | Category:免疫系統