Arousal
Arousal refers to anything that results in activation or turning on of the sympathetic nervous system and prepares the body for the upcoming sequences of the actions to be undertaken. Arousal results in increased secretion of certain body fluids, hormones and other adaptation of the body, as might be required for meeting of the immediate situation. This can be best understood with the example of sexual arousal in an individual, Sexual arousal refers to the sequential event of physical and emotional alteration that takes place as a person actively participates in activities that are sexually stimulating, this might include sexual intercourse and masturbation. there are four distinct phases of sexual arousal, as follows, the phase of Excitement, followed by the Phase 2 or the Plateau phase, then the Orgasm is reached, and finally the Resolution phase. Thus arousal is important for properly meeting a situation that the body has to encounter.