Which molecules are considered anaphylatoxins and what is their primary function?

C3a and C5a are indeed considered anaphylatoxins, which are small peptides generated during the activation of the complement system. Their primary function is to promote inflammation and recruit immune cells to sites of infection or tissue damage.

When the complement system is activated, particularly through the classical or alternative pathways, fragments such as C3a and C5a are released. These anaphylatoxins play a crucial role in enhancing vascular permeability, causing mast cell degranulation (which results in the release of histamine and other inflammatory mediators), and attracting phagocytic cells like neutrophils and macrophages to the affected area. This inflammatory response is essential for controlling infections and initiating tissue repair.

The other answer choices do not accurately describe the roles of the specified molecules, focusing instead on unrelated functions or incorrect molecular pairings. This highlights the specific and critical role that C3a and C5a play in mediating inflammatory responses in the immune system.