Seminal vesicles: clubs, coils and jelly
What are they? A pair of club-shaped glands that sit behind the bladder in men. There are two (left and right) and they each consist of a single, coiled tube. They are about 5cm long, but because they are so convoluted they are actually 10-15cm long when uncoiled. Why the name? Seminal is the adjective of semen, which literally means ‘‘ seed’’ and vesicle is from the Latin for bladder, ie a sac. What do they do? They make a sticky, yellowish secretion that exits the gland into the tube that carries sperm from the testicles, and so is mixed with the sperm to form semen. This secretion makes up about two-thirds of the volume of semen. It contains substances that give the sperm energy for its arduous swim up the female reproductive tract, such as the sweet sugar fructose. It also contains seminogelin, a jelly-like substance that holds the sperm together at ejaculation.