Even methane (natural gas) is lighter than air, but not by much. Carbon dioxide, which is contained in the air we breathe out and is also easily and safely manufactured by mixing bicarbonate of soda and vinegar, is heavier than air. It tends to sink to the floor and accumulate. So it's a good job that houses aren't air tight.
Cuddling, holding, and sexual play releases chemicals, like oxytocin, in the brain that create a sense of well-being and happiness, says Dr. Renee Horowitz, an ob-gyn who recently opened the Center for Sexual Wellness in Farmington Hills, Michigan.
Posterior Pituitary Hormones. The hormones released by the posterior pituitary are actually synthesized in the hypothalamus. They migrate along nerve fibers to the posterior pituitary, and are stored until stimulated to be released into the general circulation. Oxytocin. Oxytocin is responsible for uterine contractions, both before and after delivery. The muscle layers of the uterus (myometrium) become more sensitive to oxytocin near term.