While engaging in sexual intercourse, the stimulation of the well-innervated male reproductive organ, the penis, delivers pleasurable sensory stimuli to the brain. At the height of this pleasurable experience, a climax or orgasm is reached. An orgasm can be described as an intensely pleasurable sensation centred in the genitals that is achieved by means of sexual stimulation. Orgasm in males is generally accompanied by ejaculation. However, ejaculation and orgasms are neither the same, nor inclusive of one another. The ejaculate fluid is a white-coloured viscous liquid called semen. Semen contains sperm (the male reproductive cells that mate with the female egg to form an embryo), prostatic fluid, seminal fluid and proteins and fructose for the nourishment of the sperm. The normal physiological process of ejaculation consists of the forcible expulsion of semen stored in the testes out through the urethral meatus of the male penis. The urethra in males serves as a passage for both urine and semen.
Ejaculation occurs in two phases – emission and expulsion. The emission phase (controlled by T10-L2 spinal nerves) is sequentially described as the closure of the urinary bladder neck, followed by the secretion of sperm from the testes and secretions from the seminal vesicles, prostate and Cowper’s glands into the urethral passage. The importance of the urinary bladder neck sphincter contraction is its role in preventing the leaking of urine into the semen as well as the retrograde flow of semen into the urinary bladder. The expulsion phase involves the propulsion of the contents secreted into the urethra towards the meatal opening of the penis. The nerves controlling emission and expulsion are different and therefore the two phases occur one after the other but independent of one another.
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Retrograde ejaculation occurs when the urinary bladder neck, which contracts in the emission phase of the normal ejaculation process, fails to do so and the semen in the urethra is directed into the urinary bladder as opposed to the meatal opening of the penis. The semen that mixes with the urine in the urinary bladder as a result of urinary bladder sphincter failure is expelled out along with urine. Thus, even though the male reaches orgasm (a neurological brain response) and may experience the feeling of a rush of ejaculating, no (or negligible) semen is produced. Retrograde ejaculation is therefore also called “dry orgasm”. While it may not interfere significantly with sexual function or pleasure, the absence of semen would imply male infertility related problems while attempting to conceive a baby. Although not considered a disease and does not impact the male’s overall health, it may need diagnosis and treatment to overcome infertility.
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