Accessory Glands

c. Glands : The male accessory glands are as follows:

• Seminal vesicles : These are a paired gland lying behind the urinary bladder; they secrete an alkaline seminal fluid containing fructose, fibrinogen and prostaglandins, and contribute about 60% of the total volume of semen. The fructose in this fluid supplies energy for sperm movement, the fibrinogen helps coagulate the semen into a bolus for rapid propulsion within the vagina, and the prostaglandins stimulate reverse peristalsis of the vagina and uterus, helping the sperm move faster towards the egg inside the female body.
• Prostate gland : It is a large, single gland made up of 20–30 lobes, situated beneath the urinary bladder and surrounding the urethra; it releases a milky-white, slightly acidic prostatic fluid into the urethra, contributing about 30% of the volume of semen. This fluid contains citric acid, acid phosphatase and other enzymes, and the acid phosphatase in particular helps protect sperm from the acidic environment of the vagina.
• Cowper's gland / Bulbourethral gland : These are a small, pea-sized, paired gland situated on either side of the urethra; they secrete an alkaline, viscous, mucus-like fluid that acts as a lubricant during copulation.