Final answer:
The prostate gland secretes alkaline fluid that constitutes about 30% of semen volume and ensures sperm protection against vaginal acidity.
Step-by-step explanation:
The gland that buffers sperm against the acidity of the female reproductive tract by making seminal fluid relatively alkaline is the prostate gland. The prostate gland contributes approximately 30 percent of the semen's volume, and this fluid is rich in substances, such as zinc, that are vital for the health and motility of sperm. Another critical aspect of the seminal fluid comes from the seminal vesicles, which contribute about 60 to 70 percent of the semen. This fluid is thick, yellowish, and alkaline, containing nutrients such as fructose and ascorbic acid, coagulating enzymes, and hormones like prostaglandins, which serve to nourish and support sperm motility.
Together, these secretions from the accessory glands, including the bulbourethral gland, ensure that the sperm has the best environment for survival and successful fertilization. The prostate gland is responsible for the alkaline property of seminal fluid, protecting sperm in the acidic female reproductive tract. Semen is predominantly produced by accessory glands like the seminal vesicles and prostate gland. The seminal vesicles provide a thick, alkaline secretion that makes up most of the semen, ensuring sperm are motile in an otherwise acidic vaginal environment.