Prāṇa

Prāṇa (devanāgarī: प्राण) is the Sanskrit word for "vital life" (from the root prā). In Vedantic philosophy, prana is the notion of a vital, life-sustaining force of living beings and vital energy, comparable to the Chinese notion of Qi. In human beings, it flows through a network of fine subtle channels called nāḍis.

In the Theosophical literature prāṇa is the third (sometimes second) principle of human beings, usually referred as "life principle" or "vital principle."

In Hinduism

According to Hindu philosophy there are five pranas or vital currents that sustain physiological processes. They are:

Prāṇas

Prāṇa	Function
Prāṇa	Beating of the heart and breathing. Prana enters the body through the breath and is sent to every cell through the circulatory system.
Apāna	Elimination of waste products from the body through the lungs and excretory systems.
Uḍāna	Sound production through the vocal apparatus, as in speaking, singing, laughing, and crying.
Samāna	All metabolic processes from digestion of food to cell metabolism. Samana also includes the heat regulating processes of the body.
Vyāna	Expansion and contraction of cardio-vascular system and muscles in general.

In Theosophy

Mme. Blavatsky defines prāṇa as follows:

"Prana," or "Life," is, strictly speaking, the radiating force or Energy of Atma -- as the Universal Life and the ONE SELF, -- ITS lower or rather (in its effects) more physical, because manifesting, aspect. Prana or Life permeates the whole being of the objective Universe; and is called a "principle" only because it is an indispensable factor and the deus ex machina of the living man.

Further reading

• Prana at Theosopedia