Diseases of the prostate gland Benigh prostatic hyperplasia is an enlargement of the inner region which occurs with age. The urethra 1. The penis 1. Basic structure Corpus spongium surrounds the urethra. Corpus cavernosum provides most of the penile erectile tissue.
Arteries dilate and sinuses within the corpus spongium and cavernosum engorge with blood.
Pinched veins retain blood within erectile tissue.