Scheme illustrating the relative changes within the Sertoli cell during the reproductive cycle in the P. sinensis testis. In January (hibernation period) the Sertoli cells contain entotic vacuoles (A); during May (early spermatogenesis), they contain numerous lipid droplets (B); and in October (late spermatogenesis), there are abundant endoplasmic reticulum and mitochondria, along with well‐developed processes (C). (black spot): tight junctions; (brown red spot): adherens junctions; (silver yellow spot): hemidesmosomes; SC, Sertoli cell; Bm, basal membrane; SG, spermatogonia; DGC, degenerated germ cells; Ev, entotic vacuole; AP, autophagosomes; Ps, primary spermatocytes; Sp, spermatid; L, lipid droplets; M, mitochondria; ER, endoplasmic reticulum.