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Which glands add fluid to semen?
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human reproductive system
Organs and structures of the male and female reproductive systems.
In the human male reproductive system, three primary sets of glands contribute secretions to form semen:
- Seminal vesicles: These two saclike glands provide the bulk of the seminal fluid—approximately 60 percent of the total volume. Their secretion is thick, yellowish, and alkaline, containing fructose to nourish sperm, as well as amino acids, proteins, and prostaglandins.312
- Prostate gland: This gland contributes about 15 to 30 percent of the seminal fluid. Its secretion is thin, milky, and slightly acidic, containing enzymes, citric acid, zinc, and various ions that support sperm function.314
- Bulbourethral glands: Also known as Cowper glands, these small, pea-shaped structures secrete a clear, thick, lubricating mucus. This fluid is released early in the process to flush out the urethra and neutralize any residual acidity, creating a suitable environment for sperm.3516
Additionally, the urethral glands contribute a small amount of mucus to the ejaculate.16