Progressive Care Nursing Certification (PCCN) Practice Exam

The correct choice is platelets, as the spleen serves as a significant reservoir for this component of blood. The spleen plays a crucial role in the blood filtration system, where it not only helps remove old or damaged red blood cells but also stores healthy platelets that can be released into the bloodstream when needed, such as during a hemorrhagic event.

Platelets are essential for clotting and wound healing, making their storage in the spleen vital for rapid response to bleeding. While neutrophils and lymphocytes are important white blood cells involved in immune responses, they are predominantly found circulating in the bloodstream and within tissues rather than being stored in the spleen. Factor VIII, a blood-clotting protein, is not a blood cell but a clotting factor and is stored primarily in the endothelial cells of blood vessels and in the liver rather than in the spleen. Thus, the primary function of the spleen regarding blood components mainly pertains to the storage and regulation of platelets, making this the correct answer.