The bulbourethral glands primarily function to:

Seminal vesicle fluidis an alkaline secretion constituting about 60–70% of semen volume, rich in fructose, prostaglandins, and clotting proteins. Fructoseserves as the primary energy substrate for sperm motility by entering glycolysis within sperm cells. Normal seminal plasma fructose concentration is approximately 11–15 mmol/L. The alkaline pH (7.2–8.0) neutralizes vaginal acidity, enhancing sperm survival. Prostaglandins promote cervical mucus thinning and induce reverse peristalsis in the female reproductive tract to aid sperm transport.

Rationale for correct answers

B.Fructose in seminal vesicle fluid is the main nutrient metabolized by spermatozoa to generate ATP for motility and fertilization capability.

Rationale for incorrect answers

A.Glucose is not the predominant sugar in seminal vesicle fluid; while sperm can metabolize glucose, seminal vesicles specifically secrete fructose as their carbohydrate source.

C.Galactose is not a major component of seminal plasma; it is not secreted by seminal vesicles and has no primary role in fueling sperm.

D.Citrate is present in prostatic fluid, functioning mainly as a pH buffer and nutrient, but is not the main motility fuel in seminal vesicle secretion.

Take home points

• Seminal vesicles secrete fructose as the primary sperm energy source.
• Fructose concentration in seminal fluid can be a marker of seminal vesicle function.
• Prostatic fluid contains citrate, not fructose.
• Alkalinity of seminal fluid helps sperm survive in acidic vaginal environment.

Bulbourethral glands(Cowper’s glands) are paired exocrine glandslocated in the urogenital diaphragm, each draining into the proximal spongy urethra. They secrete an alkaline mucus-like pre-ejaculatory fluidthat neutralizes acidic urine residues in the urethra and lubricates the urethral lining. This secretion protects sperm during ejaculation by preventing acid-mediated damage and facilitating smooth passage. The alkaline pH (~7.4–8.0) of the secretion contributes to optimizing conditions for sperm viability during ejaculation.

Rationale for correct answers

B.The bulbourethral glands release alkaline mucus prior to ejaculation to neutralize urethral acidity and lubricate the passage for sperm.

Rationale for incorrect answers

A.Sperm are produced in the seminiferous tubules of the testes, not in bulbourethral glands.

C.Storage of mature sperm occurs in the tail of the epididymis, not in the bulbourethral glands.

D.Liquefaction of semen after ejaculation is mediated by PSA and other proteolytic enzymes from the prostate gland, not by bulbourethral glands.

Take home points

• Bulbourethral glands secrete alkaline mucus before ejaculation.
• Function is to neutralize urethral acidity and provide lubrication.
• Sperm production and storage occur in the testes and epididymis respectively.
• Prostate gland, not bulbourethral glands, liquefies semen post-ejaculation.