Prana

Prana is a subtle material energy arising from rajo guna. It works as an interface between gross and subtle body, enabling all the psychophysical functions (i.e. animation - from Latin "anima"). This sometimes leads to confusion of prana with jiva. Although they are very closely connected, prana is witnessed by the jiva which is floating in prana in the heart cavity. Katha Upanisad 1.3.1 says:

rtam pibantau sukrtasya loke
guham pravistau parame parardhe
chayatapau brahmavido vadanti
pancagnayo ye ca tri-naciketah

"O Naciketa, the expansions of Lord Visnu as the tiny living being (jiva) and the Supersoul both stay within the cave of the heart of this body. In that cavity the living being, resting on the main prana, enjoys the results of activities, and the Supersoul, acting as witness enables him to enjoy them. Those who are well-versed in knowledge of Brahman and those householders who carefully follow the Vedic regulations say that the difference between the two is like the difference between a shadow and the sun."

Prana's movement leads to jiva's identification with the gross body (SB 4.29.71). Prana is one but acts in different ways. Lower pranas control the senses and are under the control of main prana controlled by the Paramatma according to desire and karma of the jiva. Vedanta-sutra 2.4, Bhagavata Purana 4.25-28 (serpent analogy), Prasna Upanisad and other scriptures contain elaborate descriptions of prana. Various Eastern healing methods and martial arts work with prana.

Paraphrases of Vedanta-sutra by Suhotra Swami and corresponding Srimad Bhagavatam verses:

As the elements beginning with ether are manifest by the Supreme Lord, so too is the vital prana (life force). (Vs 2.4.1) SB 2.10.15

As was shown before, 'prana' is a name of the Supreme Lord as well as the name of the life force he creates. In the sruti-sastra, the original prana is addressed in the plural (pranah). This indicates the variegated manifestations of the one original Supreme Lord. (Vs 2.4.2) SB 2.10.36

The plurality of the word pranah cannot be applied to the created life force, because pranah is identified with 'asat.' As was shown before, asat is the state of nonmanifestation after the annihilation of the cosmos. Asat is also a name of the Supreme Lord. Hence pranah cannot refer to material variety. The variety indicated is transcendental. (Vs 2.4.3) SB 2.10.43,44

Speech exists before the cosmic manifestation. Hence prana as the name of the Supreme Lord is a word of that transcendental speech, not the mundane speech of the created world. (Vs 2.4.4) SB 6.16.51

It might be falsely argued that if the prana or life force accompanies the soul at the time of death, this prana must have no origin, just as the soul has no origin. But this standpoint is false. Prana is created, as the elements of the universe are created. (Vs 2.4.8) SB 2.10.15

It might be falsely argued on the basis of certain sastric statements that the prana or life force is the material element air (or the vibration of air, the activities of air or a condition of air). But in fact prana is created separately from that element; the scriptures likewise describe their functions separately. It is thus a special kind of air. (Vs 2.4.9) SB 2.10.15-17

It may be falsely argued that the vital prana is itself the individual spirit soul. It is really an instrument associated with the soul for as long as the soul is in material existence. (Vs 2.4.10) SB 11.3.39

The vital prana, being neutral and pervading the whole body, has no particular function like the senses. It is the soul's primary agent for governing the senses. (Vs 2.4.11) SB 4.16.12

Just as the mind is said to have multiple functions, so the prana has five functions. (Vs 2.4.12) SB 4.29.6,7

It might be falsely argued that the vital prana is all-pervading. Being the agent of the atomic soul, the vital prana is really atomic; thus it leaves the body along with the soul at the time of death. (Vs 2.4.13) SB 4.28.24

The secondary pranas activate the physical senses under the shelter of the vital prana, which is moved by the Supersoul. The pranas do not move themselves, nor are they moved by the devas, nor are they even moved by the individual spirit soul alone. (Vs 2.4.14) SB 7.2.45, 5.20.28

The Brhad-aranyaka Upanisad declares the individual soul to also be a ruler of the pranas by his enjoyment of them, for instance during sleep. The demigods are also rulers of the pranas because they define the activities of the senses. All this is under the supervision of the Supreme Lord. (Vs 2.4.15) SB 3.26.71, 6.4.25

The Supersoul is the eternal controller of the individual spirit souls and the demigods. (Vs 2.4.16) SB 5.11.13-14

The vital prana is not a sense organ, though the subordinate pranas may be taken as such because they move through the apertures of the sensory gates. (Vs 2.4.17) SB 4.28.56-58

In the Vedic description of creation, the vital prana is distinguished from the senses. Therefore it is not a sense itself. (Vs 2.4.18) SB 3.26.54

By the movement of the vital prana, the living entity maintains his conception of the body as the self. Only when the movement of the life air is arrested is the bodily identification submerged in ignorance. Thus is the prana distinguished from the senses, for even if the movements of all the senses are arrested, the bodily identification remains. (Vs 2.4.19) SB 4.29.71