3.1.1 THE FOUR PHASES OF THE RESPONSE
As described in a previous section, the anatomical difference between men and women is not very great. It is not surprising, therefore, that their sexual responses are also quite similar. There are some marked differences, but they are not decisive. In fact, one may very well speak of a basic human sexual response and its male and female variations.
During sexual activity, the human body undergoes a number of physiological changes which form a definite, typical pattern. In the simplest terms, this pattern can be described as a build up and release of tension. However, in an attempt to gain a greater understanding of the processes involved, various scientists have divided the sexual response into not only two but three or four different phases. One has to keep in mind, of course, that every individual human sexual experience is a continuous whole, and that all divisions into stages and phases are always artificial and somewhat arbitrary. Nevertheless, they can help us recognize and understand the many ways in which our bodies respond to sexual stimulation. The following description ot the male sexual response is based on the four-phase division proposed by Masters and Johnson. Although there may very well be room for finer distinctions and a more sophisticated terminology in the future, the Masters and Johnson model is quite adequate for our present purposes. (For the application of this model to females, see "The Female Sexual Response.")
Sexual excitement may mount rather unexpectedly and quickly, particularly in younger men, but it may also build up gradually over a longer period of time. In fact, some individuals deliberately distract themselves repeatedly, in order to prolong and savor their experience of becoming aroused. Especially in its early stages, sexual excitement can easily be reduced by some outside interference or by sudden anxieties or apprehensions. However, with increasing tension such negative influences become less and less effective. The ability for self-control is impaired, and the usual inhibitions are swept away.
The most obvious sign of sexual excitement in the male is the erection of his penis. The three spongy bodies inside of it (the two corpora cavernosa and the corpus spongiosum) become filled with blood and thus cause the penis to rise and stiffen. At the same time, the smooth muscles of the scrotum contract, its tissue thickens, and the testicles are pulled upward toward the abdomen by the contracting spermatic cords.
As sexual excitement increases, there is a corresponding increase in muscular tension. At the same time, the pulse rate and blood pressure rise, In addition to these symptoms, a number of men also experience what is known as a sex flush, i.e., a red rash that usually begins in the area of the lower abdomen and then spreads to the neck and face or even to the shoulders, arms, and thighs. The sex flush may start only late in the excitement phase and is more likely to appear in the plateau phase. In many cases, however, there is no sex flush at all.
This basic observation also applies to another possible phenomenon: the erection of the nipples. Not all males experience it. In some men, it may be brought about by a direct stimulation of the breasts. When nipple erection occurs, it usually appears toward the end of the excitement phase or during the plateau phase and then lasts through the other phases.
One other fact should be mentioned here: Sometimes a man may fail to achieve or maintain an erection of the penis, although he feels excited and is eager to have sexual intercourse. Obviously, in this case he is also unable to proceed to the other phases of sexual response. Such an occasional lack of erection may have many causes, but can usually be traced to particular circumstances in a specific situation. Both sexual partners should accept the incident with equanimity and perhaps turn to forms of lovemaking that do not require an erect penis. There is no cause for concern. However, if the same problem should occur frequently or even regularly, professional help may be advisable. (See "Sexual Dysfunction.")
The plateau phase is actually nothing more than the continuation of the excitement phase. The word "plateau" is meant to indicate that a certain even level of excitement has been reached which is then maintained for a while before orgasm occurs. Once sexual excitement has reached this stage, the individual is no longer easily diverted, but becomes gradually oblivious to his surroundings. With increasing sexual stimulation, the entire body experiences an increase in muscular tension, both voluntary and involuntary. At the same time, the pulse rate and blood pressure continue to rise, and breathing becomes faster.
During the plateau phase, the now erect penis does not undergo any new major changes. However, the testicles swell noticeably and are pulled close to the abdomen. The bulbourethral (Cowper's) glands secrete a few drops of a clear liquid which may appear at the tip of the penis. (Such a drop may contain some stray sperm cells. This fact should be remembered by couples who want to avoid pregnancy. Also see "Contraception—Withdrawal.")
The sex flush mentioned earlier may now appear for the first time or, if it had been visible before, grow more obvious. Again, it should be remembered that not all men show a sex flush, and that some show it only occasionally. The same is true for the erection of the nipples. However, if the nipples should become erect during the plateau phase, they will remain so through the other phases.
Orgasm (Greek orgasmos: lustful excitement) is the sudden release of muscular and nervous tension at the climax of sexual excitement. The experience represents the most intense physical pleasure of which human beings are capable and is basically the same for males and females. An orgasm lasts only a few seconds and is felt very much like a short seizure or rather a quick succession of convulsions which involve the whole body and soon lead to complete relaxation. In sexually mature males, orgasm is accompanied by the ejaculation (Latin: throwing out) of semen. Since women do not produce semen, they do not ejaculate. However, in all other respects the physiological processes are comparable to those in males.
In males, orgasm begins with involuntary rhythmic contractions of the genital ducts and accessory organs (vasa deferentia, seminal vesicles, prostate gland), the urethra, the muscles at the base of the penis and finally the penis itself. The first three or four forceful contractions recur within less than a second, then, as they become weaker, at longer intervals. As a result of these contractions, the accumulated semen is forced through the urethra to the outside where it emerges in several quick spurts. At times, it may be projected a considerable distance; at other times, it may flow out rather gently. The force of a particular ejaculation is not related to a man's strength or virility. The amount of semen ejaculated during one orgasm is usually about a teaspoonful. Repeated ejaculations within a short time produce less and less semen.
The contractions in the sex organs and the subsequent ejaculation of semen produce the most obvious signs of orgasm. However, it is important to remember that the whole body is involved. For example, the anal sphincter muscles contract at the same intervals as the sex organs mentioned above. In fact, there is great muscular tension throughout the body, breathing becomes very fast, and the pulse rate and blood pressure rise even higher than during the plateau phase. It is the sudden, convulsive release from this overall tension that constitutes orgasm. The ejaculation of semen is only incidental to this release.
Orgasm and ejaculation are two different processes. While it is true that, in men, there can be no ejaculation without orgasm, there can very well be orgasm without ejaculation. The most obvious example is the orgasm of boys before puberty. Since their internal sex organs are not yet sufficiently developed to produce semen, there is nothing that could be ejaculated. Nevertheless, these boys can have orgasms.
There are also some adult men in whom ejaculation does not occur until a few seconds after orgasm, and for whom both experiences thus remain completely separated. Certain other men who are capable of several orgasms within a short time may, for a while, exhaust their supply of semen and thus stop ejaculating as they continue to have orgasms. It should be noted, however, that only very few men are capable of multiple orgasms, and usually only while they are young. Multiple orgasms are far more common among women.
Some men claim to experience orgasm without ejaculation while practicing a technique of sexual intercourse known as "karezza" or coitus reservatus. A man who uses karezza tries not to move his erect penis very much once it has entered the vagina. This procedure aims at a spiritual union of the sexual partners who are said to reach thereby a prolonged state of bliss with repeated orgasms. However, it rather seems that at least the men remain in the plateau phase which gives them adequate satisfaction. Their "orgasms," which they may very well experience as special climaxes of intercourse, are not identical with the physiological process discussed here.
A special case is presented by a phenomenon known as retrograde ejaculation. In a few men, certain internal muscles operate in such a way that the semen is not ejaculated to the outside, but instead into the bladder from where it then later is passed off with the urine. From all external evidence these men do not seem to ejaculate at all. There are some men who claim to be able to achieve this particular muscular reaction voluntarily and use it as a means of contraception.
After orgasm the sex organs (and with them the whole body) need a relatively short time to return to their former, unexcited state. The length of this so-called resolution phase is directly proportionate to that of the excitement phase. The most visible physiological change during this period is the loss of erection which proceeds in two stages. The major loss occurs immediately after ejaculation. However, the penis still retains some firmness which may persist for some time, especially if the excitement and plateau phases were extended. On the other hand, nonsexual activities or distractions can complete the loss of erection rather rapidly.
The sex flush mentioned earlier also disappears quickly. In contrast, the erection of the nipples, if indeed it should have occurred, remains visible for some time. The muscular tension in the body subsides. Breathing, pulse rate, and blood pressure revert to normal. Some men perspire immedlately after ejaculation, although even then this reaction usually remains restricted to the palms of their hands and the soles of their feet.
Finally, it should be noted here that immediately following orgasm males experience a so-called refractory period. During this period, which extends well into the resolution phase, the individual cannot respond to any additional or new sexual stimulation, i.e., he is incapable of having another erection and another orgasm. The refractory period may be very short in some individuals, especially while they are young, but it usually becomes longer with advancing age. There may also be such a refractory period in females, although many women can experience several orgasms in rapid succession.