Detailed Explanation of Organ Changes During the Sexual Response Cycle: A Male Health Guide from Physiological Congestion to Orgasm and Ejaculation

Male and Female Sexual Organs in the Sexual Response Cycle

During the sexual response cycle, both male and female sexual organs undergo regular changes, which vary at different stages.

Let's first discuss the male:

(1) Sexual Excitement Phase. Penile erection is the sign that a man has entered the sexual excitement phase. Penile erection is the result of blood engorgement of the corpora cavernosa. During sexual excitement, the testes and scrotum rise upwards, and the scrotal wall thickens and tightens, becoming flattened. This is due to the contraction of the cremaster muscle and endometrium.

(2) Penetration Phase. During penetration, the penis has entered the vagina, and the genitals of both the man and woman are completely intertwined. The male's penis becomes further erect, hot and hard, and swollen to its maximum size. The diameter of the glans also increases slightly. Due to penile congestion, the foreskin and glans darken in color. Due to vascular congestion, the testes increase in volume by 50%, and rise upwards, reaching the perineum, indicating that ejaculation is imminent. The bulbourethral glands secrete a small amount of mucus, and a small amount of secretions flow from the urethral opening, sometimes containing a small amount of sperm. During this period, semen accumulates in the prostatic urethra to prepare for ejaculation during orgasm. These changes generally last 2–6 minutes.

(3) Orgasmic phase. During this phase, the epididymis, vas deferens, ejaculatory ducts, seminal vesicles, and prostate gland contract synchronously and rhythmically, collecting the semen accumulated in the prostatic urethra into the posterior urethra. Simultaneously, the internal urethral sphincter at the bladder neck contracts continuously, preventing semen from flowing into the bladder and preventing retrograde ejaculation. Then, the prostate, perineal muscles, and penile shaft contract violently together, generating pressure to eject semen from the posterior urethra through the external urethral opening. This contraction is a strong and uncontrollable rhythmic contraction, ejaculating the semen in 7–8 bursts.

(4) Resolution phase. After ejaculation during the orgasmic phase, the resolution phase begins. During this period, the penis begins to soften. The decline and disappearance of penile erection can be divided into two stages. In the first stage, the penile erection rapidly and partially subsides, but not completely; in the second stage, the penile erection slowly subsides, eventually becoming completely soft. The subsidence of the erect and swollen penis is due to the rapid reduction of blood flow in the corpora cavernosa, which causes the penis to soften and shrink. At the same time as the penile erection subsides, the testicles also shrink due to the reduction of blood flow and descend to the bottom of the scrotum. These changes are generally completed within 10 to 15 minutes. After the sexual resolution period, the man enters the refractory period. During the refractory period, even if sexual stimulation is present, the man cannot immediately return to the excitement period. The length of the refractory period is related to age; the refractory period for newlywed men is often only a few minutes, which is why some young men can complete multiple sexual intercourses on their wedding night.

Let's look at the regular changes in the female sexual organs during the sexual response cycle:

(1) Sexual excitement period. The nipples become erect, the superficial veins of the breasts become congested, and the blood vessels in the vagina become congested, exuding fluid and becoming lubricated. This is the main sign of female sexual arousal. Simultaneously, the inner two-thirds of the vagina undergoes spasmodic dilation, while the inner wall of the outer one-third becomes congested and thickened. The clitoris becomes erect, increasing in size by more than two times, the labia majora flatten and swell, and the uterus rises. Muscle tension is present in the legs, arms, hands, neck, lower abdomen, and pelvic region, with a sexual flush appearing on the skin, extending from the abdomen to the chest. At the same time, the heart rate increases and blood pressure rises. Newlywed women without sexual experience may experience vulvar spasms during this period.

(2) Penetration phase. The arousal and congestion of the female genitalia become more pronounced. The labia majora bulge, and the labia minora enlarge; the enlarged clitoris retracts into the clitoral hood and becomes abnormally sensitive; due to increased secretion from the vestibular glands, the vaginal vestibule becomes lubricated; vaginal exudate continues to increase, the blood vessels in the outer 1/3 of the vagina become congested and swollen, resulting in relative tightness, and the diameter of the vaginal opening can shrink by 50%, closely adhering to the inserted penis, increasing stimulation of the male penis and aiding in pleasure during penile thrusting; the inner 2/3 of the vagina further expands, reaching a diameter of 6-7.5 cm; the color of the vaginal cavity turns dark purple. Due to penile thrusting, the clitoral body is stimulated through the traction of the labia minora and clitoral hood; the cervix is ​​slightly swollen, and its color deepens and turns purple; the uterus begins to contract forcefully, lasting for about 2 minutes. At the same time, the perineum and perineum rise, exhibiting spasmodic tightening.

(3) Orgasm. The clitoris twitches 3-4 times. This throbbing motion, similar to that during ejaculation, is caused by the contraction of the perineal and genital muscles. During orgasm, the uterine muscles and the outer third of the vaginal muscles contract and spasm. The initial contractions are strong, with intervals of about 0.8 seconds, after which the intervals gradually lengthen. High-intensity orgasms can involve more than ten contractions, while moderate-intensity orgasms involve 3 to 4. This spasm and contraction of the vagina can often be felt by the partner's penis.

(4) Resolution phase. After orgasm, the resolution phase begins. During this period, the congestion in the female sexual organs gradually decreases until it fully returns to normal. The labia majora retract to their normal size within 1 to 2 minutes, and the labia minora fully recover their size and color within 5 minutes. The slowest is the clitoral body, which takes 10 to 15 minutes to return to its normal position, and about 30 minutes for the engorgement to subside and return to its original size. The vagina begins to shorten, and then the last two-thirds of the dilated vagina narrows as vaginal congestion subsides. The uterus returns to its original state within 4 minutes and fully relaxes within minutes. Women do not have a refractory period after the resolution phase and are ready for a second sexual intercourse at any time.