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Samana is located between the heart and the navel. It activates and controls the digestive system: the liver, intestines, pancreas and stomach, and their secretions. Saman activates the heart and circulatory system, and is responsible for the assimilation and distribution of nutrients.
Udana controls the area of the body above the neck, activating all the sensory receptors such as the eyes, nose and ears. Thought and consciousness of the outside world would be impossible without it. Udana also harmonises and activates the limbs and all their associated muscles, ligaments, nerves and joints, as well as being responsible for the erect posture of the body.
Vyana pervades the whole body, regulating and controlling all movement, and coordinating the other pranas. It acts as the reserve force for the other pranas.
Along with the five major pranas there are five minor pranas known as the upa-pranas. These five sub-pranas are: naga, koorma, krikara, devadatta and dhananjaya. Their functions are described as follows. Naga is responsible for belching and hiccups. Koorma opens the eyes and stimulates blinking. Krikara generates hunger, thirst, sneezing and coughing. Devadatta induces sleep and yawning. Dhananjaya lingers immediately after death and is responsible for decomposition of the body.
For further information on the pranic body, preparatory techniques and pranayama practices described in this section, refer to the Bihar School of Yoga publications, Prana Pranayama Prana Vidya and Yoga Darshan.
Prana and lifestyle Lifestyle has a profound impact on the pranamaya kosha and its pranas. Physical activities such as exercise, work, sleep, intake of food and sexual relations, all affect the distribution and flow of prana in the body. Faculties of the mind such as emotion, thought and imagination affect the pranic body even more. Irregularities in lifestyle, dietary indiscretions and stress, deplete and obstruct the pranic flow. This results in what people experience as being 'drained of energy'. Depletion of energy in a particular prana leads to the devitalisation of the
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