Orgasm (from Greek orgasmos "excitement, swelling"; also sexual climax) is the sudden discharge of accumulated sexual tension during the sexual response cycle, resulting in rhythmic muscular contractions in the pelvic region characterized by sexual pleasure. Experienced by males and females, orgasms are controlled by the involuntary or autonomic nervous system. They are often associated with other involuntary actions, including muscular spasms in multiple areas of the body, a general euphoric sensation and, frequently, body movements and vocalizations are expressed. The period after orgasm (known as a refractory period) is often a relaxing experience, attributed to the release of the neurohormones oxytocin and prolactin, as well as endorphins (or "endogenous morphine").
The health effects surrounding the human orgasm are diverse. There are many physiological responses during sexual activity, including a relaxed state created by prolactin, as well as changes in the central nervous system such as a temporary decrease in the metabolic activity of large parts of the cerebral cortex while there is no change or increased metabolic activity in the limbic ("bordering") areas of the brain. There is also a wide range of sexual dysfunctions, such as anorgasmia. These effects impact cultural views of orgasm, such as the beliefs that orgasm and the frequency/consistency of it are important or irrelevant for satisfaction in a sexual relationship, and theories about the biological and evolutionary functions of orgasm.