Sexual Response Cycle
The sexual response cycle is the sequence of events that happens physiologically when we become sexually aroused. It is divided up into four phases: excitement, plateau, orgasm, and resolution. This cycle is characterized by vasocongestion and myotonia. Vasocongestion in men causes the erection of the penis and, in women, the vaginal area to swell. The nipples and even the earlobes may swell also. Muscle tension is known as myotonia; this causes spasms in the hands and feet and causes facial grimaces and then the spasms of orgasm. The first phase in the sexual response cycle is called excitement. In women, lubrication occurs in the vaginal lining. This usually begins between 10 and 30 seconds after erotic stimulation. This lubrication is in part due to an increase in blood flow in the vaginal tissues. In both men and women the nipples may become erect and the heart rate, blood pressure, and breathing occur at an accelerated rate. This stage may last anywhere from a few minutes or less to many hours. Vasocongestion causes the penis to become erect to some degree and the clitoris to swell. The inner part of the vagina expands, the breasts enlarge, and blood vessels near the surface become more prominent. The testes increase in size during this phase and start to become elevated. The skin in the scrotal area also thickens. The second phase in the sexual response cycle is called plateau. The changes that began to take place in the first phase continue to progress during this phase until orgasm. This phase for women consists of an enlargement of the outer third of the vagina because of swelling from increased blood flow, and the color of the vagina 's walls turn a dark purple. The vaginal walls become longer and less wrinkled. The clitoris also retracts back under the clitoral hood and shortens. In men, the testes are withdrawn up into the scrotum and into position for ejaculation. They may reach one and a half times their normal size. For both men and women,
References: "Male erectile disorder n." A Dictionary of Psychology. Andrew M. Colman. Oxford University Press, 2006. Oxford Reference Online. Oxford University Press. Apollo Group. 15 February 2008 Study Shows Treatment Benefits Women With Low Sex Drive. (2001, May 10). Women 's Health Weekly, 18. Retrieved February 14, 2008, from Gale database. Rathus, S. A., & Nevid, J. S. (2004). Psychology and the challenges of life adjustment in the new millennium. Hoboken, NJ: J. Wiley.