Anatomy

The ejaculatory ducts (ductus ejaculatorii) are paired structures in male anatomy

Anatomy

Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

. Each ejaculatory duct is formed by the union of the vas deferens

Vas deferens

The vas deferens , also called ductus deferens, , is part of the male anatomy of many vertebrates; they transport sperm from the epididymis in anticipation of ejaculation....

 with the duct of the seminal vesicle

Excretory duct of seminal gland

Each seminal vesicle consists of a single tube, coiled upon itself, and giving off several irregular cecal diverticula; the separate coils, as well as the diverticula, are connected together by fibrous tissue...

. They pass through the prostate

Prostate

The prostate is a compound tubuloalveolar exocrine gland of the male reproductive system in most mammals....

, and open into the urethra

Urethra

In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...

 at the Colliculus seminalis. During ejaculation, semen

Semen

Semen is an organic fluid, also known as seminal fluid, that may contain spermatozoa. It is secreted by the gonads and other sexual organs of male or hermaphroditic animals and can fertilize female ova...

 passes through the prostate gland, enters the urethra and exits the body via the tip of the penis

Penis

The penis is a biological feature of male animals including both vertebrates and invertebrates...

.

Function in Ejaculation

Ejaculation occurs in two stages, the emission stage and the expulsion stage. The emission stage involves the workings of several structures of the ejaculatory duct; contractions of the prostate gland, the seminal vesicles and the vas deferens

Vas deferens

The vas deferens , also called ductus deferens, , is part of the male anatomy of many vertebrates; they transport sperm from the epididymis in anticipation of ejaculation....

 push fluids into the bulbourethral glands. The semen is trapped here and it is at this point that males perceive to be the point of no return for orgasm. This may be more commonly known as a male feeling as though they are "about to come". This stage is followed by the expulsion stage. Muscles at the base of the penis contract in order to propel the seminal fluid trapped in the bulbourethral glands through the urethra and expel it through the tip of the penis. The ejaculate is expelled in spurts, due to the movement of the muscles propelling it. These muscle contractions are related to the sensations of orgasm for the male.

Sperm is produced in the testes and enters the ejaculatory ducts via the vas deferens. As it passes by the seminal vesicles, a fluid rich in fructose combines with sperm. This addition nourishes the sperm in order to keep it active and motile. Seminal fluid continues down the ejaculatory duct into the prostate gland, where an alkaline prostatic fluid is added. This addition provides the texture and odor associated with semen. The alkalinity of the prostatic fluid serves to neutralize the acidity of the female vaginal tract in order to prolong the survival of sperm in this harsh environment. Semen is now a fructose-rich, alkaline fluid containining sperm as it enters the bulbourethral glands below the prostate. The bulbourethral glands secrete a small amount of clear fluid into the urethra before the ejaculate is expelled. The functions of this fluid are not entirely known but are suggested to aid in lubricating the male urethra in preparation for the semen during ejaculation. The amount of semen produced and expelled during ejaculation corresponds to the length of time that the male is sexually aroused before ejaculation occurs. The longer the period of arousal, a larger amount of seminal fluid will be produced.

Ejaculation and orgasm

Orgasm

Orgasm is the peak of the plateau phase of the sexual response cycle, characterized by an intense sensation of pleasure...

 may occur simultaneously, however they are not coupled, in that one may occur without the other. For example, a man may have a dry orgasm; there is no expulsion of ejaculate however the man still experiences orgasm. Also, paraplegics may ejaculate seminal fluid but not experience the sensation of orgasm.

Dysfunction & Abnormalities

Ejaculatory duct obstruction

Ejaculatory duct obstruction

Ejaculatory duct obstruction is a congenital or acquired pathological condition which is characterized by the obstruction of one or both ejaculatory ducts. Thus, the efflux of semen is not possible....

 is an acquired or congenital pathological condition in which one or both ejaculatory ducts are obstructed. In the case that both ejaculatory ducts are obstructed, this illness presents with the symptoms of aspermia

Aspermia

Aspermia is the complete lack of semen . Naturally, it is associated with infertility....

/azoospermia

Azoospermia

Azoospermia is the medical condition of a male not having any measurable level of sperm in his semen. It is associated with very low levels of fertility or even sterility, but many forms are amenable to medical treatment...

 and male infertility

Infertility

Infertility primarily refers to the biological inability of a person to contribute to conception. Infertility may also refer to the state of a woman who is unable to carry a pregnancy to full term...

.

Surgery to correct benign prostatic hyperplasia

Benign prostatic hyperplasia

Benign prostatic hyperplasia also known as benign prostatic hypertrophy , benign enlargement of the prostate , and adenofibromyomatous hyperplasia, refers to the increase in size of the prostate....

 may destroy these ducts resulting in retrograde ejaculation

Retrograde ejaculation

In the human male reproductive system, retrograde ejaculation occurs when semen, which would normally be ejaculated via the urethra, is redirected to the urinary bladder. Normally, the sphincter of the bladder contracts before ejaculation forcing the semen to exit via the urethra, the path of least...

. Retrograde ejaculation empties the seminal fluid formed in the emission phase into the bladder of the male instead of expelling it through the urethra and out the tip of the penis. This results in a dry orgasm, where orgasm may still be experienced but without expulsion of semen from the ejaculatory ducts.

External links

- "Lateral (A) and posterior (B) views of the bladder and associated structures."