Final answer:
True, infants and young children have significantly higher lymphocyte percentages in their peripheral blood compared to adults, reflecting their developing immune systems.
Step-by-step explanation:
True, the normal ranges for lymphocyte percentage in the peripheral blood are indeed significantly higher in infants and young children than in adults. Lymphocytes, which include both T cells and B cells, play a critical role in the immune response. T cells are involved in the cell-mediated immune response, and B cells are part of the humoral immune response. In human circulating blood, T cells constitute approximately 80 to 90 percent, and B cells account for about 10 to 20 percent of lymphocytes. While these cells are crucial for immune function in both children and adults, infants and young children have a higher percentage of lymphocytes as their immune system is still developing. Therefore, seeing higher lymphocyte percentages in younger individuals is a reflection of an immune system that is actively engaging with novel pathogens and building immunity.