Sexual Response System

The Sexual Response Cycle

The sexual response cycle was made up by Masters and Johnson to describe the changes that occur in the body as men and women become sexually aroused. It consists of four stages or phase: excitement, plateau, orgasm, and resolution. The sexual response cycle is also characterized by vasocongestion and myotonia. Vasocongestion is the engorgement of blood vessels with blood, which swells the genitals, breasts and even the earlobes during sexual arousal. Myotonia is muscle tension. It causes facial grimaces, spasms in the hands and feet and then the spasms of orgasm.

The first stage of the sexual response cycle is the excitement stage. The excitement stage can cause erection in men as soon as 3 to 8 seconds after sexual stimulation begins. The scrotal skin thickens becoming less baggy. The testes increase in size and become elevated. The second stage is the plateau phase. The plateau stage is characterized by increases in vasocongestion, muscle tension, heart rate, and blood pressure in preparation. The level of sexual arousal remains somewhat stable during the plateau stage of the cycle. Because of the vasocongestion, men show come increase in the circumference of the head of the penis, which also takes on the purplish hue. The testes are elevated into position for ejaculation and may reach one and half times their unaroused size. The next stage is the orgasmic stage. The orgasmic stage is characterized by the pelvic contractions and accompanied by intense pleasure. In males there are two stages that consist of the orgasmic phase. In the first stage semen collects are the base of the penis. The internal sphincter of the urinary bladder prevents urine from mixing in with the semen.

In the second stage muscle contractions propel the ejaculate out of the body. The first 3 to 4 contractions are generally most intense and occur at 0.8- second intervals which are 5 contractions every 4 hours. Two to four contractions occur at a somewhat...