Hi Ozura, I read your question . here is your explanation :

An orgasm (sexual climax) is the conclusion of the plateau phase of the sexual response cycle,and may be experienced by both males and females. Orgasm is characterized by intense physical pleasure,controlled by the involuntary, or autonomic, nervous system.

During orgasm, a human male experiences rapid, rhythmic contractions of the anal sphincter, the prostate, and the muscles of the penis.
A typical woman's orgasm lasts much longer than that of a man.
It is preceded by erection of the clitoris and moistening of the opening
of the vagina.
After orgasm, humans often feel tired and a need to rest.
Based on research in 2001 in UK, which focused more specifically on cardiovascular health found that having sex three or more times a week was associated with a
50% reduction in the risk of heart attack or stroke.
for more info
you can visit : http://en.wikipedia.org/wiki/Orgasm