Bulbourethral gland

Location

Bulbourethral glands are located posterior and lateral to the membranous portion of the urethra at the base of the penis, between the two layers of the fascia of the urogenital diaphragm, in the deep perineal pouch. They are enclosed by transverse fibers of the sphincter urethrae membranaceae muscle.

Structure

The bulbourethral glands are compound tubulo-alveolar glands, each approximately the size of a pea in humans. In chimpanzees, they are not visible during dissection, but can be found on microscopic examination. In boars, they are up to 18 cm long and 5 cm in diameter. They are composed of several lobules held together by a fibrous covering. Each lobule consists of a number of acini, lined by columnar epithelial cells, opening into a duct that joins with the ducts of other lobules to form a single excretory duct. This duct is approximately 2.5 cm long and opens into the bulbar urethra at the base of the penis. The glands gradually diminish in size with advancing age.

Function

The bulbourethral gland contributes up to 4 ml of fluid during sexual arousal. The secretion is a clear fluid rich in mucoproteins that help to lubricate the distal urethra and neutralize any acidic urine residue that remains in the urethra.

According to one preliminary study, the bulbourethral gland fluid might not contain any sperm, whereas another study showed some men did leak sperm in potentially significant quantities (in a range from low counts up to 50 million sperm per ml) into the pre-ejaculatory fluid, potentially leading to conception from the introduction of pre-ejaculate. However, the sperm source is a residual or pre-ejaculatory leak from the testicles into the vasa deferentia, rather than from the bulbourethral gland itself.

Gallery

File:Illu penis.jpg|Structure of the penis File:Gray1136.png|Male pelvic organs seen from right side File:Gray1156.png|Vertical section of bladder, penis, and urethra File:Gray543.png|Bulbourethral gland labeled at center left

References

References

1. Liebich, Hans-Georg. (2019-10-31). "Veterinary Histology of Domestic Mammals and Birds 5th Edition: Textbook and Colour Atlas". 5m Books Ltd.
2. (13 February 2019). "What is pre-ejaculatory fluid (also known as pre-cum), and can it cause pregnancy?". International Planned Parenthood Federation.
3. Dixson, Alan F.. (2021-06-03). "Mammalian Sexuality: The Act of Mating and the Evolution of Reproduction". Cambridge University Press.
4. (2006-08-17). "Marsupials". Cambridge University Press.
5. (1987-01-30). "Reproductive Physiology of Marsupials". Cambridge University Press.
6. Mark McEntee. (December 2, 2012). "Reproductive Pathology of Domestic Mammals". Elsevier Science.
7. Jeffrey H. Schwartz. (1988). "Orang-utan Biology". Oxford University Press.
8. ''[[Gray's Anatomy]]'', 38th ed., p 1861.
9. (2010). "Sperm content of pre-ejaculatory fluid". Human Fertility.
10. (2003). "Short Communication: Does Preejaculatory Penile Secretion Originating from Cowper's Gland Contain Sperm?". Journal of Assisted Reproduction and Genetics.