|Image from Mashable - Fuzzy line between life and death|
Ayurveda and other Yoga texts classify life force in the body into five major Pranas and five minor Pranas. Most students of Ayurveda and Yoga know the names and the actions of the five major Pranas. The major Pranas are, Prana, Apana, Udana, Vyana and Samana. However, only a few know the names of the minor pranas. Their names Naga, Krikara, Kurma, Devadatta and Dhananjaya. The last of these is responsible for the opening and the closing of the heart valve. But more esoterically, it is associated with near death situations, such as coma, trance. It does not subside until after death. The functions of the other four minor pranas are also interesting.
Link to the article in Mashable.