Spermatogenesis in a mature boar
Keywords: boar, pig, porcine, spermatogenesis, seminiferous, semen, sperm
A good illustration are spermatogenesis in a mature boar. Sertoli cells are easy to identify in this specimen. Spermatids in the tubule seen at lower left are in the Golgi phase, early in the formation of acrosomes. At lower right, spermatids are in a more advanced stage of development, the so-called "cap phase" where the acrosomes are almost completely formed. At this time the excess cytoplasm from the spermatids is being shed in the form of droplets. Usually mature spermatozoa do not have cytoplasmic droplets but is not uncommon to see cytoplasmic droplets on spermatozoa when there are slight disruptions in spermatogenesis. The very dark and condensed nuclei of spermatogonia can be used to identify their occasional presence along the basement membrane; there are seldom many spermatogonia visible in any section of seminiferous epithelium. At the top of the image, the spermatozoa are in the most advanced stage of any of those in the section, as shown by the somewhat linear and highly condensed chromatin of the spermatids, just before spermiation.
