Figure 4. The diagram depicts the relationship between the vas deferens, the seminal vesicles, the posterior aspect of the bladder and the prostate gland. The cytological features of the epithelium of the seminal vesicles is shown: this tissue is androgen dependent. Reproduced with permission from de Kretser in ‘Disturbances in Male Fertility’ Eds K Bandhauer and J Frick, Springer – Verlag Berlin.