HEALTH: The Prostate Gland

 "The prostate is a walnut-sized gland located between the bladder and the penis. The prostate is just in front of the rectum. The urethra runs through the center of the prostate, from the bladder to the penis, letting urine flow out of the body.

The prostate secretes fluid that nourishes and protects sperm. During ejaculation, the prostate squeezes this fluid into the urethra, and it’s expelled with sperm as semen.
The vasa deferentia (singular: vas deferens) bring sperm from the testes to the seminal vesicles. The seminal vesicles contribute fluid to semen during ejaculation." all info is from WebMD

There are conditions that many want to know about:

"Prostatitis: Inflammation of the prostate, sometimes caused by infection. In some cases, it is treated with antibiotics.
Enlarged prostate: Called benign prostatic hypertrophy or BPH, prostate growth affects virtually all men over 50. Symptoms of difficult urination tend to increase with age. Medicines or surgery can treat BPH.

Prostate cancer: It’s the most common form of cancer in men (besides skin cancer), but only one in 35 men die from prostate cancer. Surgery, radiation, hormone therapy, and chemotherapy can be used to treat prostate cancer. Some men choose to delay treatment, which is called watchful waiting."

It is relatively easy to check the prostate during an exam. Men who are over 40 years of age (African-American) or 50 years of age (white men) should have a check every year. If there are symptoms earlier you should get a check earlier.

The prostate is essential to ejaculation.

http://www.webmd.com/urinary-incontinence-oab/picture-of-the-prostate