Physiology of Nervous System

Physiology of Nervous System
All movements are due to ‘Vāta’ and that is why it is calledthe ‘Prānha’ of all living beings. (Ca. Sū.18/118). So, ‘Prānhavaha Srotas’ stands for the systemconcerned with the activities of ‘Vāta’. Prānhavaha Srotas’stands for the system that transports a specific type of ‘Vāta’ called‘Prānha Vāta’. This is a special Srotas meant for aspecial type of ‘Vāta’ (Cakrapānhi on Ca.Vi. 5/.

Brain and Brainstem: ‘Śiras’ (Head) is the regionwhere all ‘Prān as’ (most vital entities) are situatedand all sensory and motor activities are controlled from. That is why ‘Head’ iscalled the ‘Most important organ’ among all parts of the body (Ca. Sū. 17/12).It is described that all sensory and motor organs along with their ‘Prāanhavaha Srotāmhsi’, are connected to the brain in a fashion thatis similar to the connections between the sunrays and the Sun. (Ca. Si. 9/4).
Bhela has explained that the mind is situated in between thehead and palate. The efficiency of mind is beyond any other sensory or motororgan (Bh.Ci. 8/2-3).
Reflexes: Caraka has opined that one should notsuppress the natural urges related to micturition, defecation, ejaculation,flatus, vomiting, sneezing, eructation, yawning, hunger, thirst, tears, sleepand also dyspnoea developed after exertion (Ca. Sū. 7/3-4). It should be notedthat one or the other reflex is involved in all these activities. So, the term‘Vega’ stands almost equivalent to reflex.
Concept of ‘Vāta’: All functions of nervous system inhuman body are represented through ‘Vāta’ in Ayurveda. In general, thefunctions ascribed to ‘Vāta’ are: Control and coordination of different partsof the body, initiation of all movements, regulation of psychologicalprocesses, initiation of all activities of sense organs, transmission ofdifferent sensations, production of speech, secreto- motor functions in thegut, expulsion of wastes from the body and control of respiration (Ca.Sū.12/.‘
Vāta’ is divided into five sub types –
‘Prānha’, ‘Udāna’, ‘Vyāna’, ‘Samāna’ and ‘Apāna’.


‘Prānha Vāta’: This is situated in head and is responsible for the control overintellectual functions, cardiovascular functions, sense organs,psychological activities, respiration, and reflex activities like sneezing,belching and deglutition (A.H.Sū. 12/5). Based on this subtype of ‘Vāta’, ‘Prānhavaha Srotas’ has derived its name.

‘Udāna Vāta’: Its active site is chest region. It isbasically responsible for production of speech. The effort and strengthrequired for speech are also the functions of ‘Udāna’. It also helps in recallof vocabulary required for well-articulated speech (A.H.Sū. 12/5).

‘Vyāna Vāta’: The active site of ‘Vyāna Vāta’ isHeart. It makes the circulation of blood possible by controlling the heart.Vyana makes ‘Rasa’ (the intravascular fluid including plasma and lymph) to getforcefully ejected out of the heart and makes it circulate throughout the body(Ca. Ci. 15/36). So, sympathetic and parasympathetic control of heart isindicated by ‘Vyāna Vāta’. Some authors have ascribed the functions of somaticnervous system also to ‘Vyāna Vāta’ as movements like flexion, extension,opening and closure of eyelids have been said to be under its control (Ca. Ci.28/9).

‘Samāna Vāta’: Active site of ‘Samāna’ is adjacent togastro intestinal tract. It performs the functions like reception of food, itsdigestion through the activation of ‘Agni’, its division into useful and wasteparts and its onward propulsion (A.H. Sū. 12/. All these functions are eitherthose of parasympathetic nerves supplying the gut or those of enteric nervoussystem.

‘Apāna Vāta’: This is active in pelvic region.‘Apāna’ governs physiological processes like micturition, defecation,ejaculation, menstruation and parturition (A.H.Sū.12/9). Autonomic nervoussystem has got a definite role in most of these activities.