The sexual response cycle describes the changes that occur in the body as men and women become sexually aroused. They divided the sexual response cycle into four phases: excitement, plateau, orgasm, and resolution. The sexual response cycle is characterized by vasocongestion and myotonia. Vasocongestion is the swelling of the genital tissues with blood. It causes erection of the penis and swelling of the area surrounding the vaginal opening. The testes, the nipples, and even the earlobes swell as blood vessels dilate in these areas (yes—the earlobes). Myotonia is muscle tension. It causes facial grimaces, spasms in the hands and feet, and then the spasms of orgasm. Vasocongestion during the excitement phase can cause erection in young men as soon as 3 to 8 seconds after sexual stimulation begins. The scrotal skin also thickens, becoming less baggy. The testes increase in size and become elevated. In the female, excitement is characterized by vaginal lubrication, which may start 10 to 30 seconds after sexual stimulation begins. Vasocongestion swells the clitoris and flattens and spreads the vaginal lips. The inner part of the vagina expands. The breasts enlarge, and blood vessels near the surface become more prominent. The level of sexual arousal remains somewhat stable during the plateau phase of the cycle. Because of vasocongestion, men show some increase in the circumference of the head of the penis, which also takes on a purplish hue. The testes are elevated into position for ejaculation and may reach one and a half times their unaroused size. In women, vasocongestion swells the outer part of the vagina, contracting the vaginal opening in preparation for grasping the penis.
The Sexual Response Cycle 3
The Sexual Response Cycle
The inner part of the vagina expands further. The clitoris withdraws beneath the clitoral hood and shortens. The orgasmic phase in the male consists of two stages of muscular contractions. In...