EJACULATION / EYACULACION
(Image from Wikipedia)Ejaculation is the ejecting of semen from the penis, and is usually accompanied by orgasm. It is usually the result of sexual stimulation, which may include prostate stimulation. Rarely, it is due to prostatic disease. Ejaculation may occur spontaneously during sleep (a nocturnal emission). Anejaculation is the condition of being unable to ejaculate.
Ejaculation has two phases: emission and ejaculation proper. The emission phase of the ejaculatory reflex is under control of the sympathetic nervous system, while the ejaculatory phase is under control of a spinal reflex at the level of the spinal nerves S2-4 via the pudendal nerve. A refractory period succeeds the ejaculation, and sexual stimulation precedes it.
Emission
During emission, the two ducts known as vas deferens contract to propel sperm from the epididymis where it was stored up to the ampullae at the top end of the vas deferens. The beginning of emission is typically experienced as a "point of no return," also known as point of ejaculatory inevitability. The sperm then passes through the ejaculatory ducts and is mixed with fluids from the seminal vesicles, the prostate, and the bulbourethral glands to form the semen, or ejaculate. During ejaculation proper, the semen is ejected through the urethra with rhythmic contractions.
Ejaculation proper
These rhythmic contractions are part of the male orgasm. They are generated by the bulbospongiosus muscle. The typical male orgasm lasts about 17 seconds but can vary from a few seconds up to about a minute. 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, each bringing an extremely pleasurable sensation to the head of the penis. Once the first contraction has taken place, there is no way to voluntarily prevent ejaculation taking place. 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.
Semen content
Sertoli cells, which nurture and support developing spermatocytes, secrete a fluid into seminiferous tubules that helps transport spermatozoa to the genital ducts. The Ductuli Efferentes possess cuboidal cells with microvilli and lysosomal granules that modify the semen by reabsorbing some fluid. Once the semen enters the Ductus Epididymis the principle cells, which contain pinocytotic vessels indicating fluid reabsorption, secrete glycerophosphocholine which most likely inhibits premature capacitation. The accessory genital ducts, the seminal vesicle, prostate glands, and the bulbourethral glands, produce most of the seminal fluid. The seminal vesicles produce a yellowish viscous fluid rich in fructose and other substances that makes up ~70% of human ejaculate. The prostatic secretion, influenced by dihydrotestosterone, is a whitish, thin fluid containing proteolytic enzymes, citric acid, acid phosphatase and lipids. The bulbourethral glands secrete a clear secretion into the lumen of the urethra to lubricate it. Semen begins to spurt from the penis during the first or second contraction of orgasm. For most men the first spurt occurs during the second contraction. A small sample study of seven men showed between 26 and 60 percent of the contractions during orgasm were accompanied by a spurt of semen.
Refractory period
Most men experience a lag time between the ability to ejaculate consecutively, and this lag time varies among men. Age also affects the recovery time; younger men typically recover faster than older men though not necessarily universally so as great variation between individuals is present. During this refractory period it is somewhat difficult to attain another ejaculation. However, many men are able to enjoy sexual stimulation immediately after ejaculation and have fairly short refractory periods on the order of less than 15 or 20 minutes. This allows them to seamlessly continue sexual play from one ejaculation to another as afterplay and foreplay merge into one. Thus, a refractory period is not an unwelcome interruption for sexual activity or a period of "forced full rest" but often a perfect opportunity to turn attention productively to one's sexual partner.
Stimulation
See also: Sexual stimulation
There are wide variations in how long sexual stimulation can last before ejaculation occurs.
When a man ejaculates before he wants to it is called premature ejaculation. 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 or anorgasmia. An orgasm that is not accompanied by ejaculation is known as a dry orgasm.
Ejaculation has two phases: emission and ejaculation proper. The emission phase of the ejaculatory reflex is under control of the sympathetic nervous system, while the ejaculatory phase is under control of a spinal reflex at the level of the spinal nerves S2-4 via the pudendal nerve. A refractory period succeeds the ejaculation, and sexual stimulation precedes it.
Emission
During emission, the two ducts known as vas deferens contract to propel sperm from the epididymis where it was stored up to the ampullae at the top end of the vas deferens. The beginning of emission is typically experienced as a "point of no return," also known as point of ejaculatory inevitability. The sperm then passes through the ejaculatory ducts and is mixed with fluids from the seminal vesicles, the prostate, and the bulbourethral glands to form the semen, or ejaculate. During ejaculation proper, the semen is ejected through the urethra with rhythmic contractions.
Ejaculation proper
These rhythmic contractions are part of the male orgasm. They are generated by the bulbospongiosus muscle. The typical male orgasm lasts about 17 seconds but can vary from a few seconds up to about a minute. 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, each bringing an extremely pleasurable sensation to the head of the penis. Once the first contraction has taken place, there is no way to voluntarily prevent ejaculation taking place. 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.
Semen content
Sertoli cells, which nurture and support developing spermatocytes, secrete a fluid into seminiferous tubules that helps transport spermatozoa to the genital ducts. The Ductuli Efferentes possess cuboidal cells with microvilli and lysosomal granules that modify the semen by reabsorbing some fluid. Once the semen enters the Ductus Epididymis the principle cells, which contain pinocytotic vessels indicating fluid reabsorption, secrete glycerophosphocholine which most likely inhibits premature capacitation. The accessory genital ducts, the seminal vesicle, prostate glands, and the bulbourethral glands, produce most of the seminal fluid. The seminal vesicles produce a yellowish viscous fluid rich in fructose and other substances that makes up ~70% of human ejaculate. The prostatic secretion, influenced by dihydrotestosterone, is a whitish, thin fluid containing proteolytic enzymes, citric acid, acid phosphatase and lipids. The bulbourethral glands secrete a clear secretion into the lumen of the urethra to lubricate it. Semen begins to spurt from the penis during the first or second contraction of orgasm. For most men the first spurt occurs during the second contraction. A small sample study of seven men showed between 26 and 60 percent of the contractions during orgasm were accompanied by a spurt of semen.
Refractory period
Most men experience a lag time between the ability to ejaculate consecutively, and this lag time varies among men. Age also affects the recovery time; younger men typically recover faster than older men though not necessarily universally so as great variation between individuals is present. During this refractory period it is somewhat difficult to attain another ejaculation. However, many men are able to enjoy sexual stimulation immediately after ejaculation and have fairly short refractory periods on the order of less than 15 or 20 minutes. This allows them to seamlessly continue sexual play from one ejaculation to another as afterplay and foreplay merge into one. Thus, a refractory period is not an unwelcome interruption for sexual activity or a period of "forced full rest" but often a perfect opportunity to turn attention productively to one's sexual partner.
Stimulation
See also: Sexual stimulation
There are wide variations in how long sexual stimulation can last before ejaculation occurs.
When a man ejaculates before he wants to it is called premature ejaculation. 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 or anorgasmia. An orgasm that is not accompanied by ejaculation is known as a dry orgasm.
La eyaculación es la expulsión o emisión de semen a través del pene, acompañada de sensaciones placenteras. Las primeras eyaculaciones se suelen producir mientras se tiene un sueño erótico, a esas primeras emisiones se les llama torarquia o semenarquia.
Se suele intentar hacer que coincida con un orgasmo; mientras dura el acto sexual el hombre puede alcanzar una eyaculación cada cierto tiempo, mientras la mujer puede alcanzar varios orgasmos uno detrás de otro (multiorgasmicidad), dependiendo de la capacidad de aguante del hombre.
Si la eyaculación del hombre se produce en un tiempo que oscila entre 30 s y 7 min se puede decir que es propenso a tener eyaculación precoz. Los hombres que padecen este problema (un 30% de la población lo ha sufrido alguna vez) tardan una media de 1,8 min en eyacular, mientras que el resto tarda más de 7 a 8 min.
Sus alteraciones conllevan a problemas de la fertilidad y la sexualidad.
Tiene dos fases:
emisión
eyaculación propiamente.
La fase emisiva forma parte del "reflejo eyaculatorio", bajo control del sistema nervioso simpático, mientras que la "fase eyaculatoria" está bajo control de un reflejo espinal a nivel de la médula espinal la vía S2-4 del nervio pudendo. Durante la emisión, los dos ductos vasos deferentes se contraen para propeler espermatozoides desde el epidídimo donde estaban almacenados en la ampolla al final de dichos vasos deferentes. El momento del comienzo de la emisión se experimenta como el "punto de no retorno," o punto de inevitabilidad eyaculatoria.
El esperma que pasa a través de los ductos eyaculatorios se mezcla con fluidos de las vesícula seminales, la próstata, y la glándula bulbouretrales para formar el semen, o eyaculado.
Durante la eyaculación propia, el semen es eyectado a través de la uretra con rítmicas contracciones placenteras. La salida de semen no es continua, es espasmódica. El primer chorro, con una velocidad superior a 50 km/h, puede tener energía para alcanzar más de 2 m, este mecanismo sirve para proveer semen en lo más profundo de la vagina; los siguientes impulsos son de menor energía. La cantidad varía mucho entre razas, edades, abstinencias; no más de 3 a 5 ml por lo común (puede llegar a 15 ml). Después se produce un periodo de remisión y de resiliencia, en que, en algunas ocasiones, si se trata de estimular el glande, puede llegar a producir dolor, debido a lo sensible que se encuentra en ese momento.
Las rítmicas contracciones, sentidas por la pareja penetrada, son parte del "orgasmo masculino". Posiblemente, la media de típicos orgasmos masculinos dure cerca de 17 s; pero nuevamente varía desde pocos segundos a más de un minuto. Después de comenzado el proceso orgásmico, los pulsos de eyaculado de semen, comienzan a fluir desde la uretra, alcanzando un pico de descarga alto y luego disminuye el flujo. Un típico orgasmo consiste de entre 10 a 15 contracciones. La tasa de contracciones gradualmente declina durante este proceso orgásmico.
Las contracciones rítmicas iniciales se dan con un intervalo medio de 0,6 s con un incremento ascendente de 0,1 s por contracción. Las contracciones orgásmicas de muchos hombres proceden con intervalos rítmicos regulares por la duración del orgasmo. Y muchos también experimentan más contracciones adicionales irregulares al concluir el orgasmo. El semen comienza a expulsarse violentamente desde el pene durante la primera o con la segunda contracción del orgasmo. Para muchos hombres, el primer chorro sucede durante la segunda contracción. Un microestudio en siete hombres encontró el "chorro inicial en la 1ª contracción en 2; y en la 2ª contracción en 5. Este mismo estudio, que ha sido hecho por los siete que escribieron este artículo, mostró que entre un 26 y un 60 % de las contracciones orgásmicas se acompañaban de chorros de semen.
La fuerza y monto eyaculatorio varia enormemente de sujeto y de edad. Aparentemente, una eyaculación normal puede contener entre 1,5 a 5 mL. El volumen eyaculatorio adulto está afectado por innumerables factores, desde algunos inverosímiles para la cultura actual, como el número de mujeres o de hombres genitalmente apetecibles que permanecen en el entorno del sujeto ( dependiendo de la orientación sexual del varón ); la cantidad de tiempo de abstinencia eyaculatoria, desde la previa eyaculación. Enormes volúmenes de eyaculado correlacionan con grandes duraciones de abstinencia; y, nuevas parejas muy fantaseadas; coito absolutamente deseado y no realizado, como "ménage à trois".
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