Ejaculation

 

Ejaculation refers to the discharge of semen from the male reproductory tract as a result of an orgasm. 

 

 

It is the final stage and objective of male sexual stimulation.

 

 

Ejaculation is an essential component of natural conception. 

 

 

Rarely, ejaculation occurs because of prostatic disease, or can occur spontaneously during sleep.

 

 

The later is referred to as a nocturnal emission or wet dream.

 

 

Anejaculation refers to the  condition of being unable to ejaculate. 

 

 

Ejaculation is usually pleasurable for men.

 

 

The precursor to ejaculation is sexual arousal of the male, leading to the erection of the penis.

 

 

Not every arousal nor erection leads to ejaculation. 

 

 

The necessary penile sexual stimulus for a man to achieve orgasm and ejaculation include: masturbation or vaginal, anal, oral, or non-penetrative sexual activity..

 

 

With regard to intravaginal ejaculation latency time, men typically reach orgasm 5–7 minutes after the start of penile-vaginal intercourse.

 

 

10 minutes is a common intravaginal ejaculation latency time, taking into account their desires and those of their partners

 

 

The prolonged stimulation either through foreplay or stroking leads to arousal and production of pre-ejaculatory fluid. 

 

 

Pre-ejaculatory fluid containing  sperm is rare, although sperm from an earlier ejaculation, may be picked up by pre-ejaculatory fluid.

 

 

Infectious agents  can be present in pre-ejaculate.

 

 

Premature ejaculation occurs when ejaculation occurs before the desired time. 

 

 

The inability  to ejaculate in a timely manner after prolonged sexual stimulation, is referred to as  delayed ejaculation or anorgasmia. 

 

 

An orgasm that is not accompanied by ejaculation is known as a dry orgasm.

 

 

With a sufficient level of stimulation, the orgasm and ejaculation begins. 

 

 

Ejaculation is under the control of the sympathetic nervous system, and semen containing sperm is emitted.

 

 

Rhythmic contractions, part of the male orgasm, are generated by the bulbospongiosus and pubococcygeus muscles ejecting semen through the urethra.

 

 

These rhythmic contractions are 

 

under the control of a spinal reflex at the level of the spinal nerves S2–4 via the pudendal nerve. 

 

 

A typical male orgasm lasts several seconds.

 

 

Orgasm starts with pulses of semen flowing from the urethra, reaching a peak discharge and then diminishes in flow. 

 

 

The typical orgasm consists of 10 to 15 contractions.

 

 

It is unlikely that most contractions are experienced consciously: The rate of contractions gradually slows during the orgasm. 

 

 

Ejaculation continues to completion and it is an involuntary process, and cannot be stopped. 

 

 

Initially contractions occur at an average interval of 0.6 second.

 

 

There is an increasing increment of 0.1 seconds per contraction. 

 

 

Ejaculation contractions generally proceed at regular rhythmic intervals for the duration of the orgasm. 

 

 

Many men also experience additional irregular contractions at the conclusion of the orgasm.

 

 

Ejaculation is usually initiated during the first or second contraction of orgasm. 

 

 

For most men, the first ejection of semen occurs during the second contraction, while the second is typically the largest expelling 40% or more of total semen discharge. 

 

 

The magnitude of semen the penis emits diminishes as the contractions begin to lessen in intensity. 

 

 

Muscle contractions of the orgasm can continue after ejaculation but  no additional semen is discharged.

 

 

There is a high correlation between number of spurts of semen and total ejaculate volume.

 

 

In three-quarters of men, ejaculate is propelled with so little force that the liquid is not carried more than a minute distance beyond the tip of the penis.

 

 

In other males the semen may be propelled from a matter of some inches to a foot or two, or even as far as five or six and, rarely, eight feet (Kinsey).

 

 

Masters and Johnson analysis:  ejaculation distance to be no greater than 12–24 in.

 

 

Semen is propelled from the urethra at 500 cm/s.

 

 

The refractory period after orgasm, is the time they are unable to achieve another erection.

 

 

A longer period exists before men are capable of achieving another ejaculation. 

 

 

The duration of the refractory period varies considerably.

 

 

Age affects the recovery time, with younger men typically recovering faster than older men.

 

 

Some men may have refractory periods of 15 minutes or more.

 

 

Others are able to experience sexual arousal immediately after ejaculation. 

 

 

Some men who are able to achieve multiple orgasms, with or without the typical sequence of ejaculation and refractory period. 

 

 

The amount of semen that will be ejected during an ejaculation will vary widely between men and may contain between 0.1 and 10 milliliters.

 

 

Semen volume is affected by the time that has passed since the previous ejaculation: larger volumes are seen with greater durations of abstinence. 

 

 

The duration of the stimulation prior to ejaculation can affect the volume.

 

 

Hypospermia is the term for abnormally low semen volume, while abnormally high semen volume is known as hyperspermia. 

 

 

Low volume or complete lack of semen may be due to a an ejaculatory duct obstruction. 

 

 

The  amount of semen diminishes with age.

 

 

The number of sperm in an ejaculation also varies widely: the time since the last ejaculation, age, stress levels, and testosterone. 

 

 

Greater lengths of sexual stimulation preceding ejaculation can result in higher concentrations of sperm.

 

 

Low sperm count is known as oligospermia, and the absence of any sperm from the semen is termed azoospermia.

 

 

The first ejaculation occurs about 12 months after the onset of puberty, generally through masturbation or nocturnal emission.

 

 

Typically first semen volumes is small. producing less than 1 ml of semen. 

 

 

The semen produced during early puberty is typically clear. 

 

 

Early semen production remains jellylike and, unlike semen from mature males, fails to liquefy. 

 

 

90% of  first ejaculations lack sperm. 

 

 

In ejaculations that do contain sperm, 97% of sperm lack motion, and the remaining 3% have abnormal motion.

 

 

Semen produced 12 to 14 months after the first ejaculation liquefies after a short period of time, and within 24 months of the first ejaculation, the semen volume and the quantity and characteristics of the sperm match that of adult male semen.

 

 

The central pattern generator in the spinal cord, made up of groups of spinal interneurons, is involved in the rhythmic response of ejaculation. 

 

 

Some men can achieve ejaculations during masturbation without any manual stimulation, by tensing and flexing their abdominal and buttocks muscles along with fantasizing.

 

 

Perineum pressing can impair ejaculation which is purposefully held back, forcing  the seminal fluid to remain inside. 

 

 

No detrimental health effects have been determined from ejaculation or from frequent ejaculations.

 

 

Rarely, men have postorgasmic illness syndrome (POIS).

 

 

Postorgasmic illness syndrome causes severe muscle pain throughout the body and other symptoms immediately following ejaculation. 

 

 

Postorgasmic illness syndrome symptoms last for up to a week.

 

 

It is suggested  that frequent ejaculation after puberty offers some reduction of the risk of prostate cancer.

 

 

When men in their twenties ejaculate on average seven or more times a week, they are one-third less likely to develop aggressive prostate cancer when compared with men who ejaculated less than three times a week at this age.