Final answer:
A sexual sadist's arousal and orgasm are achieved through psychological and physiological responses to dominating behavior, which can involve inflicting pain or humiliation. The limbic system and hypothalamus play important roles in sexual motivation and response.
Step-by-step explanation:
A sexual sadist typically achieves arousal and orgasm through the act of inflicting pain or humiliation on another person. This behavior is understood through the lens of psychological and physiological mechanisms linked with sexual behavior and motivation. Physiological structures such as the amygdala and nucleus accumbens within the limbic system play a key role in sexual motivation and arousal. Damage to these areas can lead to decreased sexual motivation, while the ability to perform sexual acts remains unaffected. Meanwhile, the hypothalamus, specifically the medial preoptic area, is essential for initiating sexual behavior in male rats, suggesting a parallel for human sexual motivation. Human sexual response is complex, involving a psychological component that includes mental and emotional states, and a physiological component manifesting as four phases of sexual response, starting with excitement that includes vasodilation and vasocongestion. Sexual arousal, in this case, may be linked to a combination of dominance, control, and possibly the physiological responses of the victim. While the specifics of sexual sadism can be more complex and individualized, sexual arousal is generally achieved through behaviors that align with the sadist's particular psychological makeup and physiological sexual response patterns.