Final answer:
The sexual response cycle described by Masters and Johnson includes four phases: excitement, plateau, orgasm, and resolution. Each phase is characterized by specific physiological changes leading to and following sexual arousal and orgasm, with males experiencing a refractory period post-orgasm.
Step-by-step explanation:
The sexual response cycle, as detailed by Masters and Johnson, consists of four main phases that are parallel in both men and women but vary in intensity and duration. These phases include the excitement phase, the plateau phase, orgasm, and resolution.
- During the excitement phase, there is vasodilation leading to vasocongestion in the erectile tissues such as labia, as well as the release of vaginal secretions for lubrication.
- The plateau phase continues the stimulation, with increased engorgement of the vaginal wall, heightened heart rate, and breathing rate.
- In the orgasm phase, rhythmic, involuntary contractions of the pelvic muscles occur, accompanied by waves of uterus and vaginal muscle contractions.
- Finally, the resolution phase marks the reverse of the previous phases as the body returns to a state, which includes muscular relaxation and a decrease in blood pressure.
Additionally, men experience a refractory period following orgasm, during which they are unable to achieve another erection or ejaculation for a varying duration of time.