Visualization of an axial cut of the mail torso revealing the prostate gland. About the size of a walnut, the prostate gland is the largest accessory gland of the male reproductive system. Two thirds of the prostate is glandular while the remaining third is fibromuscular. The glandular tissue secretes a lubricant that helps to prevent infection in the urethra and protects and energizes sperm; this makes up to one third of the seminal plasma in semen. The smooth muscle of the prostate helps to expel semen upon ejaculation. The seminal vesicles also contribute to the make-up of seminal plasma: they secrete a thick alkaline fluid that mixes with the sperm as it passes into the ejaculatory ducts and the urethra.

Related content that may interest you:

Man Putting Condom on Erect Penis, Male Reproductive Organ During Ejaculation, Male Reproductive Organ, Sperm Cell Swimming Up the Fallopian Tube, Prostate Gland and Seminal Vesicle, Testicle with Exposed Internal Structure, Annular Hymen within Female External Genitalia, Sexual Intercourse cross section, Testicle Showing Seminiferous Tubule, Male Pelvis Showing Erect Penis, Male Pelvis Showing Prostate and Bladder, Male Pelvis Showing Prostate and Bladder 2, Male Pelvis Showing Prostate Gland, Sperm Penetrating Ovum, Semen Contents in Glass Vial, Male Pelvis Showing Prostate Gland 2, Penis Cross Section Showing Erectile Tissue, Normal Prostate with Erect Penis cross section, Prostate Cancer Symptoms