by the names Sasi, Mihira, and Susumna. Functions and activities In hatha yoga theory, nadis carry prana, life force energy. In the physical body, the nadis are channels carrying air, water, nutrients, blood and other bodily fluids around and are similar to the arteries, veins, capillaries, bronchioles, nerves, lymph canals and so on. In the subtle and the causal body, the nadis are channels for so-called cosmic, vital, seminal, mental, intellectual, etc. energies (collectively described as prana) and are important for sensations, consciousness and the spiritual aura. Yoga texts disagree on the number of nadis in the human body. The Hatha Yoga Pradipika and Goraksha Samhita quote 72,000 nadis, each branching off into another 72,000 nadis, whereas the Shiva Samhita states 350,000 nadis arise from the navel center, and the Katha Upanishad (6.16) says that 101 channels radiate from the heart. The Ida and Pingala nadis are sometimes in modern readings interpreted as the two hemispheres of the brain. Pingala is the extroverted (Active), solar nadi, and corresponds to the right side of the body and the left side of the brain. Ida is the introverted, lunar nadi, and corresponds to the left side of the body and the right side of the brain. Three channels (nadis) Central channel (Sushumna) Sushumna is the central and most important channel. It connects the base chakra to the crown chakra. It is important in Yoga and Tantra. Side channels Left channel (Ida) Ida is associated with lunar energy. The word ida means "comfort" in Sanskrit. Idā has a moonlike nature and feminine energy with a cooling effect. It courses from the left testicle to the left nostril and corresponds to the Ganges river. Right channel (Pingala) Pingala is associated with solar energy. The word pingala means "orange" or "tawny" in Sanskrit. Pingala has a sunlike nature and masculine energy. Its temperature is heating and courses from the right testicle to the right nostril. It corresponds to the river Yamuna. Unblocking the channels The purpose of yoga is moksha, liberation and hence immortality in the state of samadhi, union, which is the meaning of "yoga" as described in the Patanjalayayogasastra. This is obstructed by blockages in the nadis, which allow the vital air, prana, to languish in the Ida and Pingala channels. The unblocking of the channels is therefore a vital function of yoga. The various practices of yoga, including the preliminary purifications or