Male Reproductive Anatomy

The outer male reproductive anatomy includes: scrotum, testicles, penis, urethral opening and foreskin:

Scrotum & Testicles

The scrotum is a thin sac of skin that encases your testicles. A muscle called the cremaster muscle causes your scrotum to retract and pull in closer to your body if you become frightened, cold or sexually aroused. The testicles are oval in shape and produce the male sex hormone testosterone. One testicle is often larger and hangs lower than the other. The testicles produce sperm, and to effectively do so, the temperature of your scrotum is a few degrees lower than your overall body temperature (approximately 37ºC).

If a sperm comes in contact with a woman’s vulva or vaginal opening, it may travel up the vaginal canal, through the cervix and uterus to the fallopian tubes, where it can fertilize an ovum if the woman is ovulating. For more information, see the Female Reproductive Anatomy page.

Penis

The penis is comprised of soft spongy tissue. The penis fills up with blood and stiffens during sexual arousal, resulting in an erection. During this state anal or vaginal sex can occur. If stimulated enough, a man can have an orgasm and ejaculate semen out of the penis.

Despite the common term “boner” to describe a male erection, there is, in fact, no bone, muscle or cartilage in the penis. Most of the time a man’s penis is in a flaccid or soft state. The size of a penis when it is flaccid bears no resemblance to its erect size. No penis is the same, each has its own unique shape, size and colour.

Semen

When a man ejaculates, the fluid is called semen. Semen is comprised of prostate fluid, seminal fluid, fluid from the Cowper’s glands and sperm. Each ejaculation is comprised of approximately 70% seminal fluid and the remaining 30% comes from prostate fluid, sperm and fluid from the Cowper’s glands. Sperm accounts for about 1% of semen.

Urethral Opening

The urethral opening is the opening of the urethra, which is connected to the bladder. This opening is where urine (pee) passes through as well where semen passes through when a man ejaculates.

Foreskin

Foreskin is a piece of skin that covers the end of a penis. It protects the tip of the penis, which is the most sensitive part of the male anatomy. Sometimes the foreskin on a male is removed, called circumcision. Circumcision is often performed when a male is still a baby. If you are not circumcised it is important to make sure that you pull the foreskin back and clean underneath it when you bathe or shower.

Anus

The anus is the entrance to the rectum, which is connected to your bowels. Feces are released through the anus.

The internal male reproductive anatomy includes: vas deferens, prostate gland, seminal vesicles, Cowper’s glands and urethra:

Vas Deferens

The vas deferens is the long thin tube that sperm travels through during ejaculation. When a man decides that he does not want to be the father of any (more) children, a vasectomy can be performed, which is a procedure that involved severs both the right and left vas deferens. 

Prostate Gland

The prostate gland is about the size of a chestnut. It secretes prostate fluid when a man is about to ejaculate. The fluid offers nutrition to the sperm and prolongs their lifespan. Young men should begin having regular prostate exams to check for prostate cancer, prostatitis, and any other possible complications.

Seminal Vesicles

The two seminal vesicles are small glands that produce fructose, which is a sugary substance. This fluid is termed seminal fluid and it comprises 70% of the composition of semen, which nourishes the sperm.

Cowper’s Glands

The Cowper’s glands produce a small amount of fluid when a man is sexually aroused. This fluid helps neutralize the acidic climate of the urethra, so that the sperm can live longer once the man has ejaculated. The fluid is known as pre-ejaculate or pre-cum and may contain traces of sperm.

Urethra

The urethra is part of a long tube that begins with the vas deferens. The urethra is the tube that carries urine (pee) and semen to the urethral opening to be released. The urethra connects to the bladder where urine is stored. It is not possible for a man to urinate and ejaculate at the same time.

Rectum

The rectum connects the bowels and the anus, and is also where the prostate is examined.