The great ejaculatory merger

The vas deferens, which start at the tail of the epididymes, end at the ampulla, seen here.  They join the seminal vesicles, seen here in pink, and together enter the prostate, in yellow.   At this great merger, the sperm that are present in high concentration in the ampulla, pick up essential nutrients from both prostate and seminal vesicles.  The health of all e structures is critical to male fertility.