Ejaculation

EJACULATION (ejaculatio, ejaculatio seminis), the discharge of semen, begins with the movement of testicular secretions from the testicular appendages into the prostatic part of the urethra. This is preceded by the movement of testicular secretions from the seminiferous tubules into the testicular appendage, occurring under the influence of a force acting from back to front, i.e., by being pushed from behind by newly formed masses in the testicle. The movement of testicular secretions from the testicular appendages into the prostatic part of the urethra occurs under the influence of peristaltic movements of the powerful musculature of the seminal ducts. Even before ejaculation, the glands of Littré and possibly the Cooper glands moisten the mucous membrane of the urethra with their strongly alkaline secretions, which could have reacted acidly from the remnants of urine, and thereby create an alkaline reaction in the urethra necessary for the viability of spermatozoa, as well as the slipperiness of the mucous membrane, favorable for the discharge of the ejaculate. Through very strong contractions (thanks to the participation of the entire pelvic musculature) of the musculature of the seminal vesicles and prostate gland, the contents of these glands are squeezed into the prostatic part of the urethra. Prostatic juice is squeezed from the prostate gland into the urethra, probably simultaneously with the sperm; this view is supported by the location of the orifices of the prostatic excretory ducts directly under the orifices of the ejaculatory ducts on the seminal colliculus. As for the secretion of the seminal vesicles, there are many grounds to assume that it is ejected only after a certain time after the actual semen, which is liquefied by the secretions of the testicular appendages and the mucous membrane of the seminal ducts. The secretion of the seminal vesicles meets the last part of the prostatic secretion, causes its coagulation, and thus forms a denser plug that pushes ahead the more liquid sperm. In mammals, the transparent viscid-liquid secretion of the seminal vesicles, which always flows out after the actual ejaculation of sperm, pushes ahead the remnants of the seminal fluid, thereby leading to the complete emptying of the genitourinary tract, and presses them deeply into the vagina. Due to the very small capacity of the prostatic part of the urethra, even the slightest part of the ejected semen cannot be retained in it; backward, into the bladder, the semen cannot go due to the swelling of the seminal colliculus, during which the orifices of both ejaculatory ducts are pressed forward; therefore, the semen is pushed forward, into the membranous part of the urethra; from there it is pushed further by the constriction muscle of the membranous part of the urethra (Henle), since this part of the urethra is very short and expands little. If one assumes that the semen could have been retained here, then the muscle compressing the urethra would have had to overcome the force of a whole group of muscles (mm. ischio-cavernosi, mm. transversi perinaei, m. sphincter urethrae), i.e., a significantly greater force; this must be considered impossible. Therefore, the semen is ejected through the pendulous part of the penis outward. According to Walker, the longitudinal fibers of Henle's constriction muscle expand the membranous part of the urethra and thus, by suction, can favor the emptying of semen and prostatic juice into the urethra. The remaining, circular part of this constriction muscle serves to prevent the backward movement of semen during ejaculation. The movement of the combined three secretions in the urethra after they are pushed through the seminal colliculus occurs through contractions of striated musculature, namely of the following muscles: mm. bulbocavernosi (also called m. ejaculator seminis), ischio-cavernosi, transversi perinaei superficiales et profundi, and Henle's sphincter (m. sphincter partis membranaceae). The tempo of individual ejaculatory thrusts, even if one takes into account the ability of some smooth muscles to contract relatively quickly, speaks for the participation of striated muscles in ejaculation. Ejaculation occurs rhythmically at certain intervals. In healthy people, semen is ejected with considerable force. Ejaculation is completely independent of the participation of will. It is impossible to stop an ejaculation that has begun. The number of individual contractions during ejaculation varies greatly and is difficult to determine in a concrete case, since after several strong contractions there are several weak ones. This rhythm is still little studied. After ejaculation, the state of increased blood filling of the penis (see Erection) gradually passes; the blood-filled tissues return to normal the better, the more energetic the outflow (depletio), i.e., the more normally and strongly the ejaculation occurred. Ejaculation, as a rule, should be accompanied by orgasm (see Coitus), convulsive shuddering of the whole body, and reflex contractions of individual parts of the body. In some rodents (in rabbits, rats, mice), true phenomena of copulation occur during ejaculation, as a result of which the male's body slides off the female's body during ejaculation to the side and remains for a short time as if in a stupor. Ejaculation in women. By ejaculation in a woman is meant the discharge of the secretion of the cervical glands and Bartholin's glands, which occurs in a woman in the case if sexual stimulation has brought her pleasurable sensation to the point of culmination, i.e., to orgasm. During this, peristaltic contractions of the vagina occur, as a result of which the seminal mass remains at the uterine ostium under a certain pressure and the semen is pushed toward the uterus. In these peristaltic contractions, not only the vagina, cervix, and lower part of the uterus, but apparently the whole uterus participate. With strong stimulation, the uterus, with the participation of the abdominal muscles, descends lower into the pelvis, the uterine ostium opens (rounds) and ejects a small amount of secretion from the cervical canal - the cervical mucus plug; the latter is not ejected into the vagina, but remains in place. After ejaculation in a woman, the feeling of tension in the sexual organs disappears and the general hyperemia in these organs decreases. Innervation of ejaculation - see Erection.