Male - Bulbourethral Glands

1. Overview

The bulbourethral glands, also known as Cowper’s glands, are a pair of small exocrine glands in the male reproductive system. They secrete a clear, lubricating pre-ejaculatory fluid that plays a crucial role in preparing the urethra for the safe passage of sperm during ejaculation. These glands are homologous to the Bartholin’s glands in females and contribute to overall male fertility and urethral health.

2. Location

The bulbourethral glands are located in the deep perineal pouch, posterolateral to the membranous part of the urethra. Each gland is embedded within the fibers of the external urethral sphincter, near the bulb of the penis. Their ducts run obliquely and open into the proximal portion of the spongy (penile) urethra, just inferior to the urogenital diaphragm.

3. Structure

Each bulbourethral gland is approximately the size of a pea (about 0.5–1 cm in diameter) and has the following features:

• Glandular tissue: Composed of tubuloalveolar acini lined by mucus-secreting columnar epithelium.

• Capsule: Surrounded by a thin layer of smooth muscle and connective tissue.

• Ducts: Each gland has a long excretory duct (about 2.5 cm) that opens into the proximal portion of the penile urethra.

The glands are under autonomic nervous control, especially parasympathetic stimulation, which triggers secretion during sexual arousal.

4. Function

The bulbourethral glands serve several key reproductive and protective functions:

• Secretion of pre-ejaculate (pre-seminal fluid): This clear, viscous mucus lubricates the urethra and glans penis, facilitating smooth ejaculation and intercourse.

• Neutralization of acidic urine residue: The fluid helps neutralize the acidity of residual urine in the urethra, protecting sperm from acid damage.

• Cleansing the urethra: Flushes out debris or potential contaminants prior to ejaculation.

5. Physiological Role(s)

The bulbourethral glands contribute indirectly to fertility and sexual function through:

• Enhancing sperm survival: By creating a more sperm-friendly environment in the urethra.

• Facilitating penetration: The lubricating fluid eases friction during intercourse, reducing tissue trauma.

• Timing of secretion: These glands are activated during sexual arousal, secreting fluid prior to ejaculation and sometimes releasing sperm-containing fluid in the pre-ejaculate, relevant in contraceptive discussions.

Their secretory activity is controlled by parasympathetic input, often preceding the emission and ejaculation phases.

6. Clinical Significance

While small, the bulbourethral glands can be involved in several clinical conditions:

• Bulbourethral gland cysts or abscesses: Blockage of the ducts can lead to cyst formation or infection, causing perineal pain, swelling, or urethral discharge. These may require drainage or surgical removal.

• Cowperitis: Inflammation or infection of the bulbourethral glands, often due to gonorrhea or other STIs.

• Pre-ejaculate and contraception: Pre-seminal fluid may contain motile sperm, which can result in unintended pregnancy if withdrawal is used as a contraceptive method.

• Surgical relevance: These glands are carefully avoided during pelvic or urological surgeries to prevent urethral damage or complications related to continence and ejaculation.

• Aging and atrophy: In elderly men or those with reduced androgen levels, the size and function of the bulbourethral glands may diminish, potentially affecting lubrication and sexual comfort.

Proper function of the bulbourethral glands is a small but important component of male reproductive health, influencing urethral protection, fertility, and sexual performance.