ejaculation
Information about ejaculation
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. 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.[1]
These rhythmic contractions are part of the male orgasm. 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. 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 second 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.[2]
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 study of seven men found the initial spurt occurring on the first contraction for 2 men and occurring on the second contraction for 5 men. This same study showed between 26 and 60 percent of the contractions during orgasm were accompanied by a spurt of semen.[3]
The force and amount of ejaculate vary widely from male to male. A normal ejaculation may contain anywhere from 1.5 to 5 milliliters.[4] Adult ejaculate volume is affected by the amount of time that has passed since the previous ejaculation. Larger ejaculate volumes are seen with greater durations of abstinence. However, a recent Australian study has suggested a positive correlation between prostate cancer and infrequent ejaculation and/or prostate milking, which performs essentially the same function. That is, frequent masturbation appears to reduce the risk of prostate cancer. Frequent ejaculation is more easily obtained and sustained over time with the aid of masturbation and it is these ejaculations which are important, not the mechanism. [5] Also, the duration of the stimulation leading up to the ejaculation can affect the volume. Abnormally low volume is known as hypospermia, though it is normal for the amount of ejaculate to diminish with age.
The number of sperm in an ejaculation also varies widely, depending on many factors, including the recentness of last ejaculation, the average warmth of the testicles, the degree and length of time of sexual excitement prior to ejaculation, the age, testosterone level, the nutrition and especially hydration and the total volume of seminal fluid. An unusually low sperm count, not the same as low semen volume, is known as oligospermia, and the absence of any sperm from the ejaculate is termed azoospermia.
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. During this refractory period it is difficult or impossible to attain an erection, because the sympathetic nervous system counteracts the effects of the parasympathetic nervous system.
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.
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. [7]
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Diagram of the Male Reproductive System
About
The process of ejaculation is a very intense sensation and the climax of the male orgasm (French "la petite mort" - the little death), which is extremely pleasurable and satisfying. Each spurt is associated with a wave of immense sexual pleasure, especially in the penis and loins. The first and second convulsions are usually the most intense in sensation, and produce the greatest quantity of semen. Thereafter, each contraction is associated with a diminishing volume of semen and a milder wave of pleasure. During sexual intercourse or masturbation, most males will find it difficult to resist the psychological urge to continue the stimulation of the penis to the point of ejaculation once the feeling of orgasm becomes imminent.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. 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.[1]
These rhythmic contractions are part of the male orgasm. 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. 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 second 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.[2]
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 study of seven men found the initial spurt occurring on the first contraction for 2 men and occurring on the second contraction for 5 men. This same study showed between 26 and 60 percent of the contractions during orgasm were accompanied by a spurt of semen.[3]
The force and amount of ejaculate vary widely from male to male. A normal ejaculation may contain anywhere from 1.5 to 5 milliliters.[4] Adult ejaculate volume is affected by the amount of time that has passed since the previous ejaculation. Larger ejaculate volumes are seen with greater durations of abstinence. However, a recent Australian study has suggested a positive correlation between prostate cancer and infrequent ejaculation and/or prostate milking, which performs essentially the same function. That is, frequent masturbation appears to reduce the risk of prostate cancer. Frequent ejaculation is more easily obtained and sustained over time with the aid of masturbation and it is these ejaculations which are important, not the mechanism. [5] Also, the duration of the stimulation leading up to the ejaculation can affect the volume. Abnormally low volume is known as hypospermia, though it is normal for the amount of ejaculate to diminish with age.
The number of sperm in an ejaculation also varies widely, depending on many factors, including the recentness of last ejaculation, the average warmth of the testicles, the degree and length of time of sexual excitement prior to ejaculation, the age, testosterone level, the nutrition and especially hydration and the total volume of seminal fluid. An unusually low sperm count, not the same as low semen volume, is known as oligospermia, and the absence of any sperm from the ejaculate is termed azoospermia.
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. During this refractory period it is difficult or impossible to attain an erection, because the sympathetic nervous system counteracts the effects of the parasympathetic nervous system.
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.
Ejaculate development during puberty
The first ejaculation in males occurs about 12 months after the onset of puberty. This first ejaculate 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. 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. [6]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. [7]
Central nervous system control
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 [8] Expression of c-fos in the following areas have been observed: [9],[10]- 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
Fertilization
During heterosexual intercourse, the vagina provides sexual stimulation to the penis, typically resulting in orgasm and ejaculation. Normally, ejaculation is required for emission of sperm; if ejaculation happens while the penis is either near or within the woman's vagina, sperm can then travel into the uterus and fertilize an egg if present, impregnating the woman. However, almost all men produce a small amount of pre-ejaculate fluid when their penis is erect and they are sexually stimulated, and this pre-ejaculate may contain some sperm which can also lead to pregnancy. For this reason, coitus interruptus may still lead to unwanted pregnancies for couples engaging in vaginal intercourse if other forms of birth control are not used as well.Euphemisms
Because sexual topics are often an uncomfortable topic among peers, a huge variety of euphemisms and dysphemisms have been invented to describe ejaculation and semen. For a complete list of terms, see: "Sexual slang".See also
- Aspermia
- Azoospermia
- Coitus interruptus
- Coitus reservatus
- Female ejaculation
- Retrograde ejaculation
- Keri - ejaculation in Jewish law
- Mantak Chia - Author of many books of male sexuality.
References
1. ^ Walter F. Boron, Emile L. Boulpaep, (2005). Medical Physiology: A Cellular and Molecular Approach. Philadelphia, PA: Elsevier/Saunders. ISBN 1-4160-2328-3.
2. ^ Bolen, J. G., "The male orgasm: pelvic contractions measured by anal probe," Archives of Sexual Behavior, 1980 Dec;9(6):503-21.
3. ^ Gerstenburg, T. C. "Erection and ejaculation in man. Assessment of the electromyographic activity of the bulbocavernosus and ischiocavernosus muscles", British Journal of Urology, 1990 Apr;65(4):395-402.
4. ^ "Swimming Toward Conception: The Semen Analysis," Focus on Fertility, American Infertility Association and Organon Pharmaceuticals USA Inc.
5. ^ [1] "Masturbation Cuts Cancer Risk," BBC News Online 16 July 2003
6. ^ Janczewski, Z. and Bablok, L. (1985): Semen Characteristics in Pubertal Boys. Archives of Andrology 15: 199-205. [2]
7. ^ Janczewski, Z. and Bablok, L.
8. ^ Sagar SM, "et al.", "Expression of c-fos protein in brain: metabolic mapping at the cellular level", Science 240:1328-1332.
9. ^ Pfaus JG and Heeb MM, "Implications of immediate-early gene induction in the brain following sexual stimulation of female and male rodents", Brain Res Bull, 1997 44:397-407.
10. ^ Veening JG and Coolen LM, "Neural activation following sexual behavior in the male and female rat brain.", Behav Brain Res, 1998 92:181-193.
2. ^ Bolen, J. G., "The male orgasm: pelvic contractions measured by anal probe," Archives of Sexual Behavior, 1980 Dec;9(6):503-21.
3. ^ Gerstenburg, T. C. "Erection and ejaculation in man. Assessment of the electromyographic activity of the bulbocavernosus and ischiocavernosus muscles", British Journal of Urology, 1990 Apr;65(4):395-402.
4. ^ "Swimming Toward Conception: The Semen Analysis," Focus on Fertility, American Infertility Association and Organon Pharmaceuticals USA Inc.
5. ^ [1] "Masturbation Cuts Cancer Risk," BBC News Online 16 July 2003
6. ^ Janczewski, Z. and Bablok, L. (1985): Semen Characteristics in Pubertal Boys. Archives of Andrology 15: 199-205. [2]
7. ^ Janczewski, Z. and Bablok, L.
8. ^ Sagar SM, "et al.", "Expression of c-fos protein in brain: metabolic mapping at the cellular level", Science 240:1328-1332.
9. ^ Pfaus JG and Heeb MM, "Implications of immediate-early gene induction in the brain following sexual stimulation of female and male rodents", Brain Res Bull, 1997 44:397-407.
10. ^ Veening JG and Coolen LM, "Neural activation following sexual behavior in the male and female rat brain.", Behav Brain Res, 1998 92:181-193.
Physiology, endocrinology, sex: Reproductive physiology and endocrinology | |
|---|---|
| Menstrual cycle/Estrous cycle | Menstruation - Follicular phase - Ovulation - Luteal phase |
| Gametogenesis | Spermatogenesis -Oogenesis |
| Sexuality | Human sexual behavior - Sexual intercourse - Erection - Ejaculation - Orgasm - Insemination - Fertilisation/Fertility - Masturbation - Pregnancy - Postpartum period |
| Lifespan | Prenatal development - Sexual dimorphism - Sexual differentiation - Puberty (Menarche, Adrenarche) - Maternal age/Paternal age - Climacteric (Menopause, Andropause) |
| Eggs | Oviposition - Oviparity - Ovoviviparity - Viviparity |
Semen is an organic fluid (also known as seminal fluid) that usually contains spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals for fertilization of female ova. The process of discharge is called ejaculation.
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- For the symbol of the erect penis, see phallus.
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Sexual stimulation is any stimulus that leads to sexual arousal or orgasm. The term often implies stimulation of the genitals but may also include stimulation of other areas of the body, stimulation of the senses (such as sight or hearing), and mental stimulation (such as that
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The prostate is a compound tubuloalveolar exocrine gland of the male mammalian reproductive system.
The prostate differs considerably among species anatomically, chemically, and physiologically.
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The prostate differs considerably among species anatomically, chemically, and physiologically.
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Sleep is the state of natural rest observed throughout the animal kingdom, in all mammals and birds, and in many reptiles, amphibians, and fish.
In humans, other mammals, and many other animals that have been studied — such as fish, birds, ants, and fruit-flies —
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In humans, other mammals, and many other animals that have been studied — such as fish, birds, ants, and fruit-flies —
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nocturnal emission is an ejaculation of semen experienced by a male during sleep. It is also called a "wet dream", an involuntary orgasm, or simply an orgasm during sleep.
Nocturnal emissions are most common during teenage and early adult years.
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Nocturnal emissions are most common during teenage and early adult years.
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The little death is a translation from the French "la petite mort," a popular reference for a sexual orgasm. The term has generally been interpreted to describe the post-orgasmic fainting spells[1] some lovers experience.
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The loins are between the lower ribs and pelvis. It is often used when describing the anatomy of humans and quadrupeds (such as horses, pigs or cattle). The anatomical reference also carries over into the description of cuts of meat from some such animals, eg.
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Sexual intercourse or copulation is the union of the sex organs of two sexually reproducing animals.[1] The two entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails.
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The Sympathetic Nervous System (SNS) is a branch of the autonomic nervous system. It is always active at a basal level (called sympathetic tone) and becomes more active during times of stress.
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Tendon reflex (or T-reflex) is a feedback mechanism that controls increasing muscle tension by causing muscle relaxation before tension force becomes so great it may damage the muscle.
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The term spinal nerve generally refers to the mixed spinal nerve, which is formed from the dorsal and ventral roots that come out of the spinal cord. The spinal nerve is the bit that passes out of the vertebrae through the intervertebral foramen.
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The pudendal nerve is a nerve in the pelvic region that innervates the external genitalia of both sexes, as well as sphincters for the bladder and the rectum.
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Anatomy
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The vas deferens (plural: vasa deferentia), also called ductus deferens, (Latin: "carrying-away vessel") is part of the male anatomy of some species, including humans.
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A spermatozoon or spermatozoan (pl. spermatozoa), from the ancient Greek σπέρμα (seed) and ζῷον (living being) and more commonly known as a sperm cell
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The epididymis is part of the human male reproductive system and is present in all male mammals. It is a narrow, tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens.
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Ampulla may refer to:
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- A dilated segment in a tubular structure. It is used to describe several anatomical structures:
- ampulla of uterine tube
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The Ejaculatory ducts are paired structures in male anatomy, about 2 cm in length.
Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and empty into the urethra at the Colliculus seminalis.
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Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and empty into the urethra at the Colliculus seminalis.
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The seminal vesicles are a pair of simple tubular glands posteroinferior to the urinary bladder of males.
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Anatomy
They are approximately 5 cm in length, though the full length of the gland is approximately 10 cm and curled up inside of the structure...... Click the link for more information.
The prostate is a compound tubuloalveolar exocrine gland of the male mammalian reproductive system.
The prostate differs considerably among species anatomically, chemically, and physiologically.
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The prostate differs considerably among species anatomically, chemically, and physiologically.
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A bulbourethral gland (or Cowper's gland) is one of two small exocrine glands present in the reproductive system of human males. They are homologous to Bartholin's glands in females.
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Semen is an organic fluid (also known as seminal fluid) that usually contains spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals for fertilization of female ova. The process of discharge is called ejaculation.
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In anatomy, the urethra is a tube which connects the urinary bladder to the outside of the body. The urethra has an excretory function in both genders to pass urine to the outside, and also a reproductive function in the male, as a passage for sperm.
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In physics, force is an action or agency that causes a body of mass m to accelerate. It may be experienced as a lift, a push, or a pull. The acceleration of the body is proportional to the vector sum of all forces acting on it (known as net force or resultant force).
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The litre or liter (see spelling differences) is a unit of volume. There are two official symbols, namely the Latin letter L both in lower and upper case: l and L.
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Prostate cancer
Classification & external resources
ICD-10 C 61.
ICD-9 185
OMIM 176807
DiseasesDB 10780
MedlinePlus 000380
eMedicine radio/574 Prostate cancer
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Classification & external resources
ICD-10 C 61.
ICD-9 185
OMIM 176807
DiseasesDB 10780
MedlinePlus 000380
eMedicine radio/574 Prostate cancer
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Prostate massage and prostate milking are terms used to describe the massage or stimulation of the prostate gland in males, either for medical or sexual purposes. The two terms are interchangeable, although "massage" is more frequently used when the purpose is relief of
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Hypospermia is the medical term when a man has an unusually low ejaculate (or semen) volume. It should not be confused with azoospermia, which means low sperm count.
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A spermatozoon or spermatozoan (pl. spermatozoa), from the ancient Greek σπέρμα (seed) and ζῷον (living being) and more commonly known as a sperm cell
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The testicle (from Latin testis, meaning "witness",[1] plural testes) or ballock is the male generative gland in animals. This article will concentrate on mammalian testicles unless otherwise noted.
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