Describe the primary function of macrophages in the immune system.

Macrophages are responsible for phagocytosis, engulfing and ingesting pathogens and cellular debris.

What is the origin of tissue-resident macrophages, and what role do they play?

Tissue-resident macrophages originate in the fetal yolk sac and perform maintenance roles during homeostasis in almost every tissue.

Granulocytes are immune cells containing granules filled with antimicrobial chemicals. Three types are neutrophils, eosinophils, and basophils.

I can describe the structure and function of different types of blood cells.

1
Most immune cells come from hematopoietic stem cells in the bone marrow, which differentiate into either the myeloid or lymphoid lineage.
2
Macrophages are phagocytic cells that ingest pathogens and cellular debris, and granulocytes such as neutrophils, eosinophils, and basophils contain antimicrobial chemicals to kill pathogens.
3
Adaptive immune cells, including B cells and T cells, derive from the lymphoid lineage and can mount a faster and stronger reaction the next time they encounter a certain pathogen.