Sáðblöðrur

Sáðblöðrur, known scientifically as seminal vesicles, are a pair of glands in the male reproductive system. They are located posterior to the urinary bladder and superior to the prostate gland. Each seminal vesicle is a convoluted tube, about 10-15 cm long when uncoiled, but it appears as a compact, sac-like structure.

The primary function of the seminal vesicles is to produce seminal fluid, a significant component of semen. This fluid constitutes approximately 70% of the total ejaculate volume. It is an alkaline, viscous liquid rich in fructose, prostaglandins, and clotting factors. Fructose serves as the primary energy source for sperm. Prostaglandins are thought to stimulate smooth muscle contractions in the female reproductive tract, aiding sperm transport. The clotting factors help semen coagulate after ejaculation, keeping it within the female reproductive system.

During sexual arousal, the seminal vesicles contract, expelling their contents into the ejaculatory ducts. These ducts then merge with the vas deferens to form the ejaculatory ducts, which pass through the prostate gland and empty into the urethra. The seminal fluid mixes with sperm from the vas deferens and secretions from the prostate gland and bulbourethral glands to form semen.

The development and function of the seminal vesicles are regulated by androgens, primarily testosterone. Their size and secretory activity can be influenced by hormonal levels.