Ejaculation
Overview
Ejaculation is the ejecting of 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...

 (usually carrying sperm) from the male reproductory tract
Male reproductive system (human)
The human male reproductive system consists of a number of sex organs that are a part of the human reproductive process...

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

. It is usually the final stage and natural objective of male sexual stimulation
Sexual stimulation
Sexual stimulation is any stimulus that leads to, enhances and maintains sexual arousal, and may lead to ejaculation and/or orgasm...

, and an essential component of natural conception
Fertilisation
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...

. In rare cases ejaculation occurs because of prostatic disease. Ejaculation may also occur spontaneously during sleep
Sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...

 (a nocturnal emission
Nocturnal emission
A nocturnal emission involves either ejaculation during sleep for a male, or lubrication of the vagina for a female. It is also called a wet dream, and is sometimes considered a type of spontaneous orgasm....

 or "wet dream"). Anejaculation
Anejaculation
Anejaculation is the pathological inability to ejaculate in males, with or without orgasm.It can depend on one or more of several causes, including ':*Sexual inhibition*Pharmacological inhibition...

is the condition of being unable to ejaculate.
A usual precursor to ejaculation is the sexual arousal
Sexual arousal
Sexual arousal, or sexual excitement, is the arousal of sexual desire, during or in anticipation of sexual activity. Things that precipitate human sexual arousal are called erotic stimuli, or colloquially known as turn-ons. There are many potential stimuli, both physical or mental, which can cause...

 of the male, leading to the erection
Erection
Penile erection is a physiological phenomenon where the penis becomes enlarged and firm. Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is usually, though not exclusively, associated with sexual arousal...

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

, though not every arousal nor erection leads to ejaculation.
Encyclopedia
Ejaculation is the ejecting of 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...

 (usually carrying sperm) from the male reproductory tract
Male reproductive system (human)
The human male reproductive system consists of a number of sex organs that are a part of the human reproductive process...

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

. It is usually the final stage and natural objective of male sexual stimulation
Sexual stimulation
Sexual stimulation is any stimulus that leads to, enhances and maintains sexual arousal, and may lead to ejaculation and/or orgasm...

, and an essential component of natural conception
Fertilisation
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...

. In rare cases ejaculation occurs because of prostatic disease. Ejaculation may also occur spontaneously during sleep
Sleep
Sleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...

 (a nocturnal emission
Nocturnal emission
A nocturnal emission involves either ejaculation during sleep for a male, or lubrication of the vagina for a female. It is also called a wet dream, and is sometimes considered a type of spontaneous orgasm....

 or "wet dream"). Anejaculation
Anejaculation
Anejaculation is the pathological inability to ejaculate in males, with or without orgasm.It can depend on one or more of several causes, including ':*Sexual inhibition*Pharmacological inhibition...

is the condition of being unable to ejaculate.

Stimulation

A usual precursor to ejaculation is the sexual arousal
Sexual arousal
Sexual arousal, or sexual excitement, is the arousal of sexual desire, during or in anticipation of sexual activity. Things that precipitate human sexual arousal are called erotic stimuli, or colloquially known as turn-ons. There are many potential stimuli, both physical or mental, which can cause...

 of the male, leading to the erection
Erection
Penile erection is a physiological phenomenon where the penis becomes enlarged and firm. Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is usually, though not exclusively, associated with sexual arousal...

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

, though not every arousal nor erection leads to ejaculation. Penile sexual stimulation
Sexual stimulation
Sexual stimulation is any stimulus that leads to, enhances and maintains sexual arousal, and may lead to ejaculation and/or orgasm...

 during vaginal, oral or anal sexual intercourse
Sexual intercourse
Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which a male's penis enters a female's vagina for the purposes of sexual pleasure or reproduction. The entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails...

, or manual stimulation
Masturbation
Masturbation refers to sexual stimulation of a person's own genitals, usually to the point of orgasm. The stimulation can be performed manually, by use of objects or tools, or by some combination of these methods. Masturbation is a common form of autoeroticism...

 (masturbation) may provide the necessary stimulus for a man to achieve orgasm
Orgasm
Orgasm is the peak of the plateau phase of the sexual response cycle, characterized by an intense sensation of pleasure...

 and ejaculation. Men typically reach orgasm 5–10 minutes after the start of penile-vaginal intercourse, taking into account their desires and those of their partners. Most men could achieve orgasm sooner or delay it until later if they wished to do so. A prolonged stimulation either through foreplay (kissing, petting and direct stimulation of erogenous zones before penetration during intercourse) or stroking (during masturbation) leads to a good amount of arousal and production of pre-ejaculatory fluid
Pre-ejaculate
Pre-ejaculate is the clear, colorless, viscous fluid that emits from the urethra of a man's penis when he is sexually aroused. It is similar in composition to semen, but has some significant chemical differences...

. While the presence of sperm in pre-ejaculatory fluid is thought to be rare, sperm from an earlier ejaculation, still present in the urethra, may be picked up by pre-ejaculatory fluid. In addition, infectious agents (including HIV) often can be present in pre-ejaculate.

Premature ejaculation
Premature ejaculation
Premature ejaculation is a condition in which a man ejaculates earlier than he or his partner would like him to. Premature ejaculation is also known as rapid ejaculation, rapid climax, premature climax, or early ejaculation....

 is when ejaculation occurs before the desired time. If a man is unable to ejaculate in a timely manner after prolonged sexual stimulation, in spite of his desire to do so, it is called delayed ejaculation
Delayed ejaculation
Delayed ejaculation is the inability to ejaculate or persistent difficulty in achieving orgasm despite the presence of normal sexual desire and sexual stimulation...

 or anorgasmia
Anorgasmia
Anorgasmia, or Coughlan's syndrome, is a type of sexual dysfunction in which a person cannot achieve orgasm, even with adequate stimulation. In males the condition is often related to delayed ejaculation . Anorgasmia can often cause sexual frustration...

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

Ejaculation

When a man has achieved a sufficient level of stimulation, ejaculation begins. At that point, under the control of the sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...

, 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...

 containing sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...

 is produced (emission). The semen is ejected through 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...

 with rhythmic contractions. These rhythmic contractions are part of the male orgasm. They are generated by the bulbospongiosus muscle
Bulbospongiosus muscle
Bulbospongiosus is one of the superficial muscles of the perineum. It has a slightly different origin, insertion and function in males and females. In males, it covers the bulb of the penis...

 under the control of a spinal reflex at the level of the spinal nerve
Spinal nerve
The term spinal nerve generally refers to a mixed spinal nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body...

s S2-4 via the pudendal nerve
Pudendal nerve
The pudendal nerve is a sensory and somatic nerve in the pelvic region which is a large branch of the sacral plexus that innervates the external genitalia of both sexes, as well as sphincters for the bladder and the rectum...

. The typical male orgasm lasts several seconds.

After the start of orgasm, pulses of semen begin to flow from the urethra, reach a peak discharge and then diminish in flow. The typical orgasm consists of 10 to 15 contractions, although the man is unlikely to be consciously aware of that many. Once the first contraction has taken place, ejaculation will continue to completion as an involuntary process. At this stage, ejaculation cannot be stopped. The rate of contractions gradually slows during the orgasm. Initial contractions occur at an average interval of 0.6 seconds with an increasing increment of 0.1 seconds per contraction. Contractions of most men 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 begins during the first or second contraction of orgasm. For most men the first spurt occurs during the second contraction. The first or second spurt is typically the largest and can contain 40 percent or more of the total ejaculate volume. After this peak the flow of each pulse diminishes. When the flow ends, the muscle contractions of the orgasm continue with no additional semen discharge. A small sample study of seven men showed an average of 7 spurts of semen (range between 5 and 10) followed by an average of 10 more contractions with no semen expelled (range between 5 and 23). This study also found a high correlation between number of spurts of semen and total ejaculate volume, i.e., larger semen volumes resulted from additional pulses of semen rather than larger individual spurts.

Alfred Kinsey
Alfred Kinsey
Alfred Charles Kinsey was an American biologist and professor of entomology and zoology, who in 1947 founded the Institute for Sex Research at Indiana University, now known as the Kinsey Institute for Research in Sex, Gender, and Reproduction, as well as producing the Kinsey Reports and the Kinsey...

 measured the distance of ejaculation, in "some hundred" of men. In three-quarters of men, the 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...

 exuded from 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 (rarely eight) feet". Masters and Johnson
Masters and Johnson
The Masters and Johnson research team, composed of William H. Masters and Virginia E. Johnson, pioneered research into the nature of human sexual response and the diagnosis and treatment of sexual disorders and dysfunctions from 1957 until the 1990s....

 report ejaculation distance to be not greater than 30–60 cm. Distance of ejaculation however, has nothing to do with sexual functioning, as during penetration of penis in vagina the distance of ejaculation plays no role. Dribbling of semen from the penis is usually sufficient for impregnation.

Refractory period

Most men experience a refractory period
Refractory period (sex)
In sexuality, the refractory period is the recovery phase after orgasm during which it is physiologically impossible for an individual to have additional orgasms. Most men are unable to maintain or achieve an erection during this time, and many perceive a psychological feeling of "satiation" and...

 immediately following an orgasm, during which time they are unable to achieve another erection, and a longer period again before they are capable of achieving another ejaculation. During this time a male feels a deep and often pleasurable sense of relaxation, usually felt in the groin and thighs. The duration of the refractory period varies considerably, even for a given individual. Age affects the recovery time, with younger men typically recovering faster than older men, though not universally so.

However, some men are able to achieve sufficient sexual arousal immediately after ejaculation, and others may have refractory periods of fewer than 15 minutes. A short recovery period may allow them to seamlessly continue sexual play from one ejaculation to sexual stimulation in preparation for the next. However, other men are averse to stimulation during the early part of the refractory period.

There are men who are able to achieve multiple orgasms, with or without the typical sequence of ejaculation and refractory period. Some of those men report not noticing refractory periods, or are able to maintain erection by "sustaining sexual activity with a full erection until they passed their refractory time for orgasm when they proceeded to have a second or third orgasm".

Volume

The force
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...

 and amount of 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...

 that will be ejected during an ejaculation will vary widely between men and may contain between 0.1 and 10 milliliters. (By way of comparison, note that a teaspoon
Teaspoon
A teaspoon, an item of cutlery, is a small spoon, commonly part of a silverware place setting, suitable for stirring and sipping the contents of a cup of tea or coffee...

 is 5 ml and a tablespoon holds 15 ml.) Adult semen volume is affected by the time that has passed since the previous ejaculation; larger semen volumes are seen with greater durations of abstinence. It is not clear whether frequent ejaculation increases, reduces or has no effect on the risk of prostate cancer. The duration of the stimulation leading up to the ejaculation can affect the volume. Abnormally low volume is known as hypospermia
Hypospermia
Hypospermia is the medical term when a man has an unusually low ejaculate volume, it is the logical opposite of Hyperspermia. It should not be confused with Oligospermia, which means low sperm count....

. One of the possible underlying causes of low volume or complete lack of semen is 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....

. It is normal for the amount of semen to diminish with age.

Quality

The number of sperm
Spermatozoon
A spermatozoon is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote...

 in an ejaculation also varies widely, depending on many factors, including the time since the last ejaculation, age, stress levels, and testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

. Greater lengths of sexual stimulation immediately preceding ejaculation can result in higher concentrations of sperm. An unusually low sperm count, not the same as low semen volume, is known as oligospermia
Oligospermia
Oligospermia, also oligozoospermia, refers to semen with a low concentration of sperm and is a common finding in male infertility. Often semen with a decreased sperm concentration may also show significant abnormalities in sperm morphology and motility...

, and the absence of any sperm from the semen is termed 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...

.

During puberty

The first ejaculation in males often occurs about 12 months after the onset of puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

, generally through masturbation
Masturbation
Masturbation refers to sexual stimulation of a person's own genitals, usually to the point of orgasm. The stimulation can be performed manually, by use of objects or tools, or by some combination of these methods. Masturbation is a common form of autoeroticism...

 or nocturnal emission
Nocturnal emission
A nocturnal emission involves either ejaculation during sleep for a male, or lubrication of the vagina for a female. It is also called a wet dream, and is sometimes considered a type of spontaneous orgasm....

 (wet dreams). This first 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...

 volume is small. The typical ejaculation over the following three months produces less than 1 ml of semen. The semen produced during early puberty is also typically clear. After ejaculation this early semen remains jellylike and, unlike semen from mature males, fails to liquify
Liquefaction
Liquefaction may refer to:* Liquefaction, the general process of becoming liquid* Soil liquefaction, the process by which sediments become suspended* Liquefaction of gases in physics, chemistry, and thermal engineering* Liquefactive necrosis in pathology...

. A summary of semen development is shown in Table 1.

Most first ejaculations (90 percent) lack sperm. Of the few early ejaculations that do contain sperm, the majority of sperm (97%) lack motion. The remaining sperm (3%) have abnormal motion.

As the male proceeds through puberty, the semen develops mature characteristics with increasing quantities of normal sperm. Semen produced 12 to 14 months after the first ejaculation liquifies after a short period of time. Within 24 months of the first ejaculation, the semen volume and the quantity and characteristics of the sperm match that of adult male semen.
Semen development during puberty
Time after first
ejaculation (months)
Average volume
(milliliter)
Liquefaction Average sperm concentration
(million sperm/milliliter)
0 0.5 No 0
6 1.0 No 20
12 2.5 No/Yes 50
18 3.0 Yes 70
24 3.5 Yes 300

Ejaculate is jellylike and fails to liquify.

Most samples liquify. Some remain jellylike.

Ejaculate liquifies within an hour.

Control from the central nervous system

To map the neuronal activation of the brain during the ejaculatory response, researchers have studied the expression of c-fos, a proto-oncogene expressed in neurons in response to stimulation by hormones and neurotransmitters. Expression of c-fos in the following areas has been observed:
  • medial preoptic area (MPOA)
  • lateral septum, bed nucleus of the stria terminalis
  • paraventricular nucleus of the hypothalamus (PVN)
  • ventromedial hypothalamus, medial amygdala
  • ventral premammillary nuclei
  • ventral tegmentum
  • central tegmental field
  • mesencephalic central gray
  • peripeduncular nuclei
  • parvocellular subparafascicular nucleus (SPF) within the posterior thalamus

Health issues

For most men, no detrimental health effects have been determined from ejaculation itself or from frequent ejaculations, though sexual activity in general can have health or psychological consequences. A very small percentage of men may experience a transient Postorgasmic illness syndrome following ejaculation.

See also

  • 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...

  • Coitus interruptus
    Coitus interruptus
    Coitus interruptus, also known as the rejected sexual intercourse, withdrawal or pull-out method, is a method of birth-control in which a man, during intercourse withdraws his penis from a woman's vagina prior to ejaculation...

  • Coitus reservatus
    Coitus reservatus
    Coitus reservatus , also known as sexual continence, is commonly thought of as a form of sexual intercourse in which the penetrative partner does not attempt to ejaculate within the receptive partner, but instead attempts to remain at the plateau phase of intercourse for as long as possible...

  • Cum shot
    Cum shot
    A cum shot, cumshot, come shot, pop shot, or money shot are slang terms used to describe a person ejaculating , usually onto a person or object. It is typically used by the cinematographer within the narrative framework of a pornographic film, and since the 1970s has become a leitmotif of the...

  • Fertilization
  • 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...

  • Spermatorrhea
    Spermatorrhea
    Spermatorrhea is a condition of excessive, accidental ejaculation.It is a recognized disorder in Traditional Chinese Medicine, in which certain patterns of involuntary ejaculation reflect problems with kidney qi....

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