Erection is a functional increase in the volume and tension of the penis. Erection allows you to perform sexual intercourse and enter the seed into the vagina. It occurs as a result of increased arterial blood flow into the corpus cavernosum, an increase in pressure in the arteries supplying the blood to the penis, ie, a simultaneous decrease in the outflow of venous blood. Erection is the result of a clear interaction of nerves, arteries, veins and muscles. Violation of the filling of cavernous bodies with blood is most often due to disorders of the nervous system that regulates sexual function. In rare cases, erectile dysfunction can be associated with the pathology of blood vessels or perineal muscles, which to some extent also participate in erection.
Erections can arise as a simple reflex, proceeding at the level of the spinal cord, but can also appear with the participation of the higher part of the nervous system – the cortex of the brain.
An erection that appears as a reflex at the level of the spinal cord is usually caused by irritation of the nerve endings of the glans penis. Excitation passes through the dorsal nerve of the penis and through the pudendal nerve to the center of the erection, located in the sacral spine (segments I-III). Parasympathetic fibers emerge from this center, which through the pelvic nerves pass to the pelvic ganglia, and then, like postganglionic fibers (nn. Erigentes), they reach the cavernous bodies, in which they cause corresponding changes.
Most often, erections arise as a result of the action of stimuli of the sense organs (visual, tactile, auditory, olfactory) that enter the cerebral cortex, and from it into the sexual centers of the interstitial brain. Hence stimuli are transmitted to the oblong and spinal cord. Some of them reach the center of the erection, located in the sacral region of the spinal cord, and excites it. Some stimuli are already in the upper lumbar segments “branch off” and pass through the sympathetic fibers emerging from the lumbar segments, and then through the hypogastric plexus directly to the penis or clitoris. In this way, the erection is caused by mental stimuli. They are transmitted directly to the penis or clitoris, bypassing the center of the erection in the spinal cord. This was shown in an experiment on dogs that were crossed spinal cord between the lumbar and sacral segments. Despite the complete disruption of the integrity of the spinal cord and the consequent impossibility of psychic stimuli entering the center of the erection in the sacral segments, an erection appeared in the males at the sight of the female. This means that the “mental” erection occurs irrespective of the center of the erection in the spinal cord, due to the arrival of stimuli through the pudend nerves, outgoing from the spinal cord above the injury site.
Erection can also occur without irritations transmitted from peripheral sensory receptors. This is because the cerebral cortex can create this kind of stimulation with the help of imagination and imagination. The further passage of these excitations coincides with that described above.
According to Masters, Johnson A966), penile erection is the first physiological response in the stimulation phase to effective sexual stimulation. The expression of erection is not directly proportional to the level of sexual arousal. There are cases when a full erection occurs with a very weak sexual arousal, and weak erections (or even their complete absence) can take place despite very strong sexual arousal. Continuation of the phase of sexual arousal can be accompanied by a changing intensity of erections, which depends on more or less effective methods of stimulation. Non-existent stimuli (noise, change of situation, etc.) can cause weakening or even complete the disappearance of an erection despite continued sexual stimulation.
In the plateau phase, the diameter of the penis slightly increases, primarily its head. The color of the head also changes, resembling a patchy red-purple color caused by stagnation of venous blood. Change in color is observed only in 20% of men and not in every cycle of sexual reactions, ie, it is a sign of a fickle.
In the phase of orgasm, convulsive contractions of the penis occur with intervals between the first contractions of 0.8 seconds. These abbreviations provide the discharge of the seed to the urethra of the urethra. After the first contractions, the subsequent ones are marked less often and they are weaker; While all smaller portions of the seed are thrown out and with less force. The convulsive contractions of the penis result from coordinated contractions of the muscle group – urethra constrictor, bulbous-spongy, ischiocerepid and pelvic floor muscles.
In the relaxation phase, the voltage and volume of the penis quickly decrease first, but then this process slows down. If the phase of excitation or the phase of the plateau has been deliberately prolonged, then the first (fast) phase of detemination of the penis is delayed. The time of complete detemntsentsii penis also depends on the influence of many stimuli, which either contribute to a certain extent, sexual stimulation, or, conversely, divert the attention of men from sexual reactions. The disappearance of the erection after ejaculation occurs more slowly if the penis remains in the vagina, since in this case the stimulating effect of the stimuli continues due to direct contact of the penis with the vagina.
According to Bancroft A971), the intensity of erections can be used to determine the severity of the body’s reaction to sexual stimuli. However, the general excitement accompanying an erection can not be measured in this way, in accordance with the statement that changes in excitation can be established by various psychophysiological methods, which, however, do not reveal the level of the sexual component in the state of excitation. For practical purposes, sexual arousal can be defined as the sum of general excitement and specific sexual reactions. But with this definition, sexual arousal should be assessed in two ways: by the specific gravity of the component of general excitation and the component of a specifically sexual one. It should be remembered that: 1) an erection experienced as a sexual reaction, can also be caused by non-sexual irritants; In general, the evaluation of erection is a fairly reliable indicator of sexual interest by a particular pathogen (under natural conditions and provided that the erection is so pronounced that the man feels it); 2) the reliability of assessing the intensity of erection with respect to a particular sexual behavior or orientation to sexuality is small, although it can help in determining sexual preferences; 3) the indication of the changes in the erection during the treatment depends on the importance of the erection for the sexual behavior modified by treatment; However, it can not be concluded that changes in the erection reflect violations in sexual behavior or attitudes towards sexuality.
The structures that control the erections and are located in the hypothalamus are closely connected with the structures responsible for various vegetative functions anatomically and functionally. With the help of conditioned connections it is possible to cause changes in heart rate, peristalsis, urine output, etc., which indicates that vegetative reactions can to a certain extent depend on the will of a person. Henson, Rubin (1971), referring to the data obtained by Laws, Rubin, believe that healthy men can to some extent control the erections of the penis. Thus, we are talking about a vegetative reaction, which, it is believed, does not lend itself to strong-willed management. Examined (selectively) men could induce erections without erotic stimuli, and also suppress erection in the presence of these stimuli. At the same time they caused erections, representing erotic scenes, and they tried to slow down the erections by switching attention to non-sexual stimuli. Some men could suppress erections even without concentration of attention. On non-sexual irritants. The involuntary inhibition of erections during the concentration of attention
On the content of the sexual stimulus indicates that the vegetative reaction responsible for erection can be at least partially modified by strong-willed effort.
Erection of the penis can arise as a substitute form of other actions. Halverson (1940) noted that male infants may develop an erection after weaning from his vessel with food during the sucking period. According to Wolff (1965), erections in infants may occur in place of others autonomous and motor categories. At the same time, a child with brain damage and priapism had an erection when he was held and fed.
Kinsey et al. (1948) found that many non-erotic stimuli, such as listening to a national anthem, looking at a name printed in a newspaper, etc., can cause erections in adolescents.
Hastings (1963) pointed out that morning erections are not the result of a purely mechanical effect of the overflowing bladder (during the day the filled bladder does not cause such reactions), but may be a criterion of potential sexual attraction or manifestation of sexual biorhythm. All of the above information also applies to the erection of the clitoris.
Schnabl (1974) emphasizes that the phallus is a prerequisite for sexual intercourse. In the mind of a man, he became a symbol of masculinity, which many men appreciate depending on the size of the penis and its ability to erect. Revaluation of the phallus as a criterion of male power and ability to sexual satisfaction of a woman is largely involved in the pathogenesis of erectile dysfunction in men.