Accessory Ducts, Glands and Semen

From the seminiferous tubules, newly formed sperm follow a defined route out of the body. Each lobule's tubules converge into a short tubulus rectus, which feeds into the rete testis, a network of channels on the back of the testis; from there sperm pass through the vasa efferentia into the epididymis, a single, very long, tightly coiled tube where sperm are stored and undergo genuine physiological maturation — gaining the motility and fertilising capacity they lack when they first arrive. The epididymis continues into the vas deferens, which joins the duct of the seminal vesicle to form the ejaculatory duct; this passes through the prostate gland and empties into the urethra, the shared terminal channel that carries both urine and semen (at different times) out through the penis. Three glands add fluid to make semen. The paired seminal vesicles contribute an alkaline seminal plasma rich in fructose (an energy source for sperm), ascorbic acid, prostaglandins and a coagulating enzyme, and supply by far the largest share of the fluid. The single prostate gland, wrapped around the urethra just below the bladder, adds a slightly acidic fluid containing citrate, various enzymes and prostate-specific antigens. The paired bulbourethral (Cowper's) glands, below the prostate, add a lubricating secretion. The penis itself is the male copulatory organ, its enlarged tip (the glans penis) covered by a retractable fold of skin, the foreskin or prepuce. A related clinical fa …