In 1966 gynecologist William Masters quiz help psychologist Virginia Johnsonwho firstly hailed from Washington University before founding their very own analysis institute in St. Louisdescribed for the first time the sexual response cycle how the body responds exam help sexual stimulation, in response to observations of 382 women quiz help 312 men undergoing some 10,000 such cycles. The cycle begins with excitation, as blood rushes examination help the in men, quiz help as the clitoris, vulva quiz help vagina magnify quiz help grow moist in women. Gradually, people reach exam help plateau, during which they may be fully aroused but not yet at orgasm. After attaining orgasm, they enter the determination phase, by which the tissues return exam help the preexcitation stage. In the 1970s psychiatrist Helen Singer Kaplan of the Human Sexuality Program at Weill Medical College of Cornell University added exam help vital element examination help this cycledesirebased on her adventure as exam help therapist.