Within the male reproductive system are two small glands known as the bulbourethral glands, or Cowper’s glands. These structures are classified as exocrine glands, which means they produce and secrete substances through a duct. As accessory glands, they are not involved in producing sperm but contribute a fluid that prepares the urethra for the passage of sperm during sexual arousal.
Anatomy and Location of the Gland
The bulbourethral glands are a pair of pea-sized structures located at the base of the penis, just below the prostate gland. They sit on either side of a section of the urethra known as the membranous urethra. Anatomically, they are situated superior to the bulb of the penis.
Each gland is a compound tubulo-alveolar gland, composed of many small tubes and sacs that produce its secretion. A fibrous capsule encloses each gland, holding the lobules within. From each gland, a duct approximately 2.5 to 3 centimeters long extends to open into the urethra. This connection allows the fluid produced by the glands to be released directly into the urethral tract.
The Role of Pre-Ejaculate
Upon sexual arousal, the bulbourethral glands secrete a clear, viscous fluid known as pre-ejaculate, or Cowper’s fluid. This fluid serves two main purposes. The first is to neutralize any residual acidity within the urethra from urine. The alkaline nature of the pre-ejaculate counteracts this acidic environment, creating a safer pathway for sperm.
The second function is lubrication of the distal urethra and the tip of the penis, which reduces friction for the passage of semen during ejaculation. The secretion can also clear the urethra of any remaining urine or cellular debris. The amount of pre-ejaculate released can vary from a few drops up to 5 milliliters.
A common question is whether pre-ejaculate can contain sperm and lead to pregnancy. The fluid produced by the bulbourethral glands does not contain sperm. However, some studies have shown that sperm can be present in the pre-ejaculate. This is believed to happen when sperm from a previous ejaculation remain in the urethra and are then carried out by the Cowper’s fluid.
Associated Health Conditions
While issues with the bulbourethral glands are uncommon, several conditions can affect them. Cowperitis is an inflammation or infection of the gland, often caused by bacteria responsible for urinary tract infections. This can lead to symptoms like severe pain in the perineum, fever, and discomfort during urination or defecation.
Another condition is a Cowper’s syringocele, a cyst that forms when the gland’s duct becomes blocked. This blockage causes fluid to build up, creating a cyst that can sometimes be felt as a lump. While many are asymptomatic, larger ones can press on the urethra, leading to difficulties with urination like a weak stream or urinary retention.
Rarer conditions can also affect the glands. Calcium stones can form within the glands or their ducts, causing blockages or infections. Adenocarcinoma, a type of cancer, can also develop in the bulbourethral glands, though this is exceptionally rare. This growth can cause a narrowing of the urethra and may present with pelvic pain or bloody discharge.