The process of ejaculation is immensely pleasurable and most satisfying for males. Each spurt is associated with a wave of 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 temptation to continue the stimulation of the penis to the point of ejaculation once the feeling of orgasm becomes imminent. During the process, males may make involuntary vocalizations such as grunting, groaning, or crying out, and some may experience full body convulsions, the spasms in tempo with those in the penis.
Ejaculation has two phases: emission and ejaculation proper. During emission, the two ducts known as vas deferens contract to propel sperm from the epididymis (where it was stored) up to the ampullas 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.
These rhythmic contractions are part of the male orgasm. The typical male orgasm last 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 procede at regular rhythmic intervals for the duration of the orgasm. Many men also experience additional irregular contractions at the conclusion of the orgasm.
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 occuring on the first contraction for 2 men and occuring 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
The force and amount of ejaculate vary widely from male to male. A normal ejaculation may contain anywhere from 2 to 15 milliliters (from half a teaspoon to a tablespoon), although 1.5 to 5.0 ml is typical. [3] 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. 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 general fertility of the subject, 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.
The ejaculation reflex is caused by the sympathetic nervous system, while erection of the penis is caused by the parasympathetic nervous system. Most men experience a lag time of some half-hour or so between the ability to ejaculate consecutively. 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 intercourse can last before ejaculation occurs. Studies have shown that most men can only avoid ejaculation during active thrusting for five minutes or less.
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. |
