The prostate gland produces semen. It is situated close to the tube, which is called the urethra.

About the prostate

The prostate is a small gland about the size of a walnut. The prostate gets bigger as men get older. It is divided into 2 lobes and has an outer layer called the capsule.

The prostate is below the bladder surrounding the first part of a tube called the urethra. The urethra carries pee (urine) from the bladder to the penis. The same tube also carries semen, which is the fluid containing sperm. Just behind the prostate is the back passage (rectum). There are also some lymph nodes (sometimes called glands) near the prostate.

The prostate contains muscle tissue and glandular tissue. Glandular tissue is tissue that releases (secretes) certain substances.

Male reproductive system

What does the prostate do?

The prostate produces a fluid that mixes with sperm (from the testicles) to make semen. The fluid is kept in a tube-shaped gland that sits behind the bladder. This gland is called the seminal vesicle. During sex, the muscle tissue helps force (ejaculate) prostate fluid and sperm into the urethra.

The male sex hormone testosterone (made in the testicles) controls how the prostate works. Testosterone is responsible for things like your sex drive, getting an erection, and muscle development.

The prostate also produces a protein called prostate-specific antigen (PSA). This helps to make semen more watery. A blood test can measure PSA. This is called a PSA test. Doctors use it to help diagnose different prostate problems, including cancer.

About our information

  • References

    Below is a sample of the sources used in our prostate cancer information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    European Association of Urologists. Guidelines on Prostate Cancer. 2016.

    European Society for Medical Oncology. Cancer of the prostate: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. 2015.

    National Institute for Health and Care Excellence (NICE). Prostate cancer overview. Available from: pathways.nice.org.uk/pathways/prostate-cancer (accessed from March 2017 to November 2017).

    National Institute for Health and Care Excellence (NICE). Surveillance report 2016. Prostate cancer: diagnosis and management (2014). NICE guideline CG175. 2016.



  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editors, Dr Jim Barber, Consultant Clinical Oncologist and Dr Lisa Pickering, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.