The membranous portion of the urethra is approximately three-quarters of an inch long and lies between the triangular ligaments of the male pelvis. The spongy portion is the longest part of the urethra, which extends through the body of the penis and exits at the glans. The urethra is surrounded and protected by the corpus spongiosum. The production of sperm, or spermatogenesis, is a complicated process of cell division. The spermatids then mature and are transformed into spermatozoa, or sperm cells.
Spermatogenesis usually occurs among groups of cells.
Such groups, or generations of sperm, pass through the same developmental stages together. Within the ductal network of the seminiferous tubules, six developmental stages make up one spermatogenesis cycle - each of which lasts approximately 16 days. So, sperm that are mature now may have been affected by risk factors that were present 2 to 3 months ago. LH stimulates testosterone production. As the sperm mature, they are stored in the upper compartment of the tubules.