The mind and the body must work together for normal sexual function. Thoughts and emotions interact with the nervous, circulatory, and endocrine (hormone) systems of the body to produce a sexual response. The sexual response has four stages:
1. Desire (the wish to engage in sexual activity) is triggered by thought or verbal and visual cues.
2. Arousal (the state of sexual excitement) occurs as blood enters the genital area, leading to an erection in the male.
3. Orgasm (the climax of sexual excitement) occurs at ejaculation (the emis- sion of semen from the penis); muscle tension increases throughout the body.
4. Resolution (a sense of well-being and complete muscle relaxation) follows orgasm.