MaleReproFIG 23: Ultrastructure of FB-MO in maturing sperm.

TEM of FB-MO in maturing spermatids and spermatozoa showing the highly condensed nuclei and tightly packed mitochondria, transverse view. The collar region of the FB-MO is indicated by white arrows. (Image source: him5-25 [Hall] 2631.) (SV) Seminal vesicle.