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Human Body Study

Accessory Glands

Three sets of glands that produce most of the fluid of semen. The sperm themselves make up only a small fraction of what is ejaculated; the rest comes from these glands.

Male reproductive system Front-view schematic showing the testes, duct system, accessory glands and penis; each labelled part links to its article. Male reproductive system bladder prostate Accessory glands the seminal vesicles, prostate, and bulbourethralglands, which produce the fluid of semen. Duct system the epididymis (where sperm mature and arestored) and the vas deferens (which carriessperm onward). Penis the organ of delivery; its urethra is sharedwith the urinary system. Testes produce sperm and the hormone testosterone;held in the scrotum, outside the body, for theslightly cooler temperature sperm need. Male reproductive system — schematic front view, not to scale.

The three glands

Section titled “The three glands”
  • Seminal vesicles — paired pouches behind the bladder; contribute most of the fluid volume, rich in fructose to fuel the sperm.
  • Prostate — a walnut-sized gland surrounding the urethra below the bladder; adds a milky alkaline fluid that activates the sperm and neutralizes vaginal acidity.
  • Bulbourethral (Cowper’s) glands — small paired glands below the prostate; release a clear lubricating fluid into the urethra before ejaculation.

What they do

Section titled “What they do”

Each gland contributes a distinct fluid; together they make up the semen, which protects, fuels and powers the sperm on their journey.

Key idea

Section titled “Key idea”

The accessory glands turn raw sperm into a delivery-ready fluid. The prostate is the most clinically significant of the three — it commonly enlarges with age and is a frequent site of cancer.