When immature sperm are sloughed into the lumen of the seminiferous tubule, they must be transported out of the testis to the duct system. The sperm exit the testis through the efferent ductules to mature as they travel the length of the epididymis. The epididymis is 4-6 m long, and therefore is coiled extensively to fit on the dorsal surface of the testis, so there are many sections through it in different planes of section (HA5). Note the abundant sperm (arrows) in the lumens. Compare HA5 to HA2 to see the differences between the epithelia.