My approach to Vaata with physiological perspective ; Cikitsā Sthāna Chapter 28 Vātavyādhi Cikitśītām..Verse 4 ;
The functional status of Vāta with its sub units can be better understood by analyzing certain physiological events. The normal electrical conduction in the heart allows the impulse that is generated by the sinoatrial node (SA node) of the heart to be propagated to, and stimulate, the cardiac muscle (myocardium). The myocardium contracts after stimulation. It is the ordered, rhythmic stimulation of the myocardium during the cardiac cycle that allows efficient contraction of the heart, thereby allowing blood to be pumped throughout the body. Signals arising in the SA node (located in the right atrium) stimulate the atria to contract and travel to the AV node, which is located in the interatrial septum. After a delay, the stimulus diverges and is conducted through the left and right Bundle of His to the respective Purkinje fibers for each side of the heart, as well as to the endocardium at the apex of the heart, then finally to the ventricular epicardium.
On the microscopic level, the wave of depolarization propagates to adjacent cells via gap junctions located on the intercalated disk. The heart is a functional syncytium (not to be confused with a true “syncytium” in which all the cells are fused together, sharing the same plasma membrane as in skeletal muscle). In a functional syncytium, electrical impulses propagate freely between cells in every direction, so that the myocardium functions as a single contractile unit. This is the avyāhata gati of vāta which is necessary for the rapid, synchronous depolarization of the myocardium. Conduction from SA to AV to bundles and Purkinje fiber is the aparityakta swa mārga of vāta. This rhythmical and conductive system of the heart is susceptible to damage by heart disease, especially by ischemia of the heart tissues resulting from poor coronary blood ﬂow. The result is often a bizarre heart rhythm or abnormal sequence of contraction of the heart chambers, and the pumping effectiveness of the heart often is affected severely, even to the extent of causing death. This explains the vyāhata gati of vāta which is the cause of death.
The circulatory system is the main method for blood transportation within body. This system is a complex highway of vessels, and its main purpose is to move blood and nutrients throughout body. The circulatory system is also responsible for exchanging gases and removing waste products from body. Unlike an open circulatory system, a closed circulatory system is more structured and controlled. The blood of a closed system always flows inside vessels. These vessels make up the plumbing circuit of the body and can be found throughout the entire body. This plumbing circuit can be broken down into three different types of vessels, or tubes that transport blood throughout the body: arteries, capillaries and veins. Thus a continuous flow of blood from Left ventricles to the aorta to arteries all over the body than to arterioles into capillaries into venules into veins and back to the right atrium than right ventricle via pulmonary artery to the lungs and via pulmonary veins to the left atrium and back to left ventricle. This is how blood is propagated from heart to the periphery and back to the heart. The modern explanation resembles Caraka explanation as mentioned in Ca. Ci. 15/36
This function of vāta is swa sthānastha which helps to maintain the homeostasis or swāsthya but when avarodh to this gati takes place may be due to any reason the swa mārgāsthita vāta gets vimārga gata as explained in samprapti of śōtha (Ca. Ci. 12/8).
Various edemas are either due to excessive secretion (apāna vāyu) or reduced absorption (prāna vāyu) as understood in samprapti of udara. Disturbed concentration of solutes and solvents causes changes in pressure (vyāna vāyu) either intravascular or extra vascular. The electrolyte balance is brought about by sweda dōṣa ambu srotas sthāyi vāyu i.e. samāna vāyu.
Prakruti sthita vāta is the one which is akshina vridha:
Reduced respiratory rate due to depressed respiratory centre explains kshina prāna vāyu whereas vridha prāna vāyu may be one of the causes for increased ventilation.
Prayatna, urjā are functions of udāna vāyu. Excessive excitation of cell due to excess action potential explains the vridha udāna vāyu whereas inhibition of cell activity due to reduced action potential is due to kshina udāna vāyu.
Excessive stimulation of agni (atyagni) causes increased appetite one reason being vridha samāna vāta whereas agnimāndya, grahani etc may be caused by decrease stimulation of agni by samāna vāta.
Normal pulse rate ranges from 60-80/min. Excessive pulse rate explains the repeated contraction of heart one of the cause being excessive ākunchan prasārana karma of vyāna vridhi whereas one of the cause of bradycardia may be kshina vyāna vāyu.
Increased peristalsis is the cause for increased frequency of stools one of the reason being vridha apāna vāta whereas reduced peristalsis causes constipation one reason being kshina apāna vāta.
Modern anatomical or functional correlation of subtypes of vāta is attempted here for a rough and overall understanding for beginners. Prāna Vāyu is concerned with consciousness, arousal, heartbeat, vomiting, breathing, cough, hiccup etc. The modern functional analogue may be compared with brain stem and reticular formation which directly control cardiovascular / respiratory systems, pain sensitivity, alertness, awareness, and consciousness. Udāna is concerned with language, learning, mood, initiation, judgment, intellect, recall information etc. The prefrontal cortex, sub cortical areas and parts of limbic system along with association areas may be understood as functional areas of Udāna. Vyāna is concerned with control of skeletal muscle activities, control of hemodynamics, sweating etc. Post-lateral and dorso-medial hypothalamus – sympathetic stimulator, primary motor area, basal ganglia, extra pyramidal tract and autonomous nervous system are part and parcel of vyāna vāta. Samāna and Apāna can be considered together. Gastro Intestinal Tract based enteric nervous system (2nd brain), (brain- gut axis – more than 100 million neurons), celiac plexus, sacral plexus etc may be analogue for apāna and samāna.
The functioning of panch vāta prakār can be also understood by understanding the physiology of sensation. In its broadest deﬁnition, sensation is the conscious or subconscious awareness of changes in the external or internal environment. The nature of the sensation and the type of reaction generated vary according to the ultimate destination of nerve impulses that convey sensory information to the CNS. Sensory impulses that reach the spinal cord may serve as input for spinal reﬂexes, such as the stretch reﬂex, sensory impulses that reach the lower brain stem elicit more complex reﬂexes, such as changes in heart rate or breathing rate. When sensory impulses reach the cerebral cortex, person become consciously aware of the sensory stimuli and can precisely locate and identify speciﬁc sensations such as touch, pain, hearing, or taste. Perception is the conscious awareness and interpretation of sensations and is primarily a function of the cerebral cortex. Person may have no perception of some sensory information because it never reaches the cerebral cortex. For example, certain sensory receptors constantly monitor the pressure of blood in blood vessels. Because the nerve impulses conveying blood pressure information propagate to the cardiovascular center in the medulla oblongata rather than to the cerebral cortex, blood pressure is not consciously perceived. Thus some functions may involve all the panch prakāra vāta and in some their permutation and combination.
Process of sensation
An appropriate stimulus must occur within the sensory receptor’s receptive ﬁeld, that is, the body region where stimulation activates the receptor and produces a response.
A sensory receptor transduces (converts) energy in a stimulus into a graded potential. Conversion of energy from one form to another i.e. transformation is the function of agni but the one which stimulates the agni is the samāna vāyu (agni samipasta and swedavaha (at the level of tvak) āshrayi vāta prakar). For example, odorant molecules in the air stimulate olfactory (smell) receptors in the nose, which transduces the molecules’ chemical energy into electrical energy in the form of a graded potential.
When a graded potential in a sensory neuron reaches threshold, it triggers one or more nerve impulses, which then propagate toward the CNS. It explains the sarvasrotogata vyāna vāta action to take the nerve impulse towards the CNS. A particular region of the CNS receives and integrates the sensory nerve impulses. Conscious sensations or perceptions are integrated in the cerebral cortex. Integration is the role of antahkarana but carried out by niyanta ca manasā i.e. vāta especially the prāna vāyu in this case.
A characteristic of most sensory receptors is adaptation, in which the generator potential or receptor potential decreases in amplitude during a maintained, constant stimulus. Because of adaptation, the perception of a sensation may fade or disappear even though the stimulus persists. For example, when you ﬁrst step into a hot shower, the water may feel very hot, but soon the sensation decreases to one of comfortable warmth even though the stimulus (the high temperature of the water) does not change. This is the smriti kriya exhibited by the antahkaran but now with the help of udāna vāyu.
Many somatic motor neurons are regulated by the brain. When activated, somatic motor neurons convey motor output in the form of nerve impulses along their axons, which sequentially pass through the anterior gray horn and anterior root to enter the spinal nerve. From the spinal nerve, axons of somatic motor neurons extend to skeletal muscles of the body. This is again the function of vyāna. Thus afferent conduction of nerve impulse is the urdhwagati of vyāna, conduction from motor neurons to the skeletal muscle is the adhogati of vyāna and the autonomic nervous stimulation is the tiryaka gati of vyāna vāyu. This is the reason why Caraka in context of treatment of vāyu prakār has told “tridha vyānam tu yojayet” it explains vyāna has all the three gati which need to be regularize during the treatment.
The part of the body that responds to the motor nerve impulse, such as a muscle or gland, is the effector. Its action is called a reﬂex. If the effectors are skeletal muscle, the reﬂex is a somatic reﬂex. If the effectors are smooth muscle, cardiac muscle, or a gland, the reﬂex is an autonomic (visceral) reﬂex.
Depending on the resultant action function of vāta prakāra have been explained i.e. ṣṭhīvana, kṣavathū, anna pravesh, udgār, niswasa karma is seen that it is due to prāna vāyu.
Vākpravr̥tti, prayatna, urjā, bala varna smriti are karma of udāna vāyu.
Anna vivechan, agni bala prada karma is due to samāna vāyu whereas ākuncan prasāran is due to vyāna vāyu and garbha, mūtra, purisa niskraman is due to apāna vāyu.
Thus the classification done is on the gross level of functioning. Similarly at cellular level too one can understand the existence of panch prakar vāta.
The selective permeability of the plasma membrane allows a living cell to maintain different concentrations of certain substances on either side of the plasma membrane. A concentration gradient is a difference in the concentration of a chemical from one place to another, such as from the inside to the outside of the plasma membrane. Many ions and molecules are more con- centrated in either the cytosol or the extracellular ﬂuid. For instance, oxygen molecules and sodium ions (Na) are more concentrated in the extracellular ﬂuid than in the cytosol; the opposite is true of carbon dioxide molecules and potassium ions (K). The plasma membrane also creates a difference in the distribution of positively and negatively charged ions between the two sides of the plasma membrane. Typically, the inner surface of the plasma membrane is more negatively charged and the outer surface is more positively charged. A difference in electrical charges between two regions constitutes an electrical gradient. Because it occurs across the plasma membrane, this charge difference is termed the membrane potential. In many cases a substance will move across a plasma membrane down its concentration gradient. That is to say, a substance will move “downhill,” from where it is more concentrated to where it is less concentrated, to reach equilibrium. Similarly, a positively charged substance will tend to move toward a negatively charged area, and a negatively charged substance will tend to move toward a positively charged area. The combined inﬂuence of the concentration gradient and the electrical gradient on movement of a particular ion is referred to as its electrochemical gradient.
Transport of materials across the plasma membrane is essential to the life of a cell. (āyu is one of the paryāya of vāyu). Certain substances must move into the cell to support metabolic reactions (pravesakrita karma of prāna vāyu). Other substances that have been produced by the cell for export or as cellular waste product (niskramana karma of apāna vāyu) must move out of the cell.
The concentration gradient which is maintained is essential for cellular activity. Resting membrane potential and active membrane potential are maintained at specific levels. For e.g. Charges of -90 mv is the resting charge which reaches to +35 mv when depolarized in cardiac cell thus this knowledge of potential gradient is due to budhi dharan karma of prāna which cause the pumping of Na/K pump to activate. Thus knowledge of concentration gradient is karma of prāna vāyu. Further prāna means prinana ādāna karma i.e. helping entry/ facilitation of such ions, essential requirements within cell which will do prinan /poshan is also due to prāna. Thus process that initiates endocytosis is prāna vāyu.
Substances generally move across cellular membranes via transport processes that can be classiﬁed as passive or active, depending on whether they require cellular energy. In passive processes, a substance moves down its concentration or electrical gradient to cross the membrane using only its own kinetic energy. The continuous movement resembles the cala guna, a common quality of all the types of vāta. Modern describes it as the Brownian movement of the ions. Kinetic energy is intrinsic to the particles that are moving. There is no input of energy from the cell. An example is simple diffusion.
In active processes, cellular energy is used to drive the substance “uphill” against its concentration or electrical gradient. The cellular energy used is usually in the form of ATP. It explains the prayatna karma of udāna vāyu which is responsible for the activity. An example is active transport. Active transport is considered an active process because energy is required for carrier proteins to move solutes across the membrane against a concentration gradient. Two sources of cellular energy can be used to drive active transport: (1) Energy obtained from hydrolysis of adenosine triphosphate (ATP) is the source in primary active transport; (2) energy stored in an ionic concentration gradient is the source in secondary active transport. Like carrier-mediated facilitated diffusion, active transport processes exhibit a transport.
Many of the infolding of the inner membrane form shelves on which oxidative enzymes are attached. In addition, the inner cavity of the mitochondrion is ﬁlled with a matrix that contains large quantities of dissolved enzymes that are necessary for extracting energy from nutrients. These enzymes operate in association with the oxidative enzymes on the shelves to cause oxidation of the nutrients, thereby forming carbon dioxide and water and at the same time releasing energy. The liberated energy is used to synthesize a “high-energy” substance called adenosine triphosphate (ATP). ATP is then transported out of the mitochondrion, and it diffuses throughout the cell to release its own energy wherever it is needed for performing cellular functions. Thus the phenomenon which triggers the oxidative process is the samāna vāyu which stimulates the oxidation i.e. role of agni.
The intracellular movement of proteins, ATP transfer, and vesicle transportation can be understood as the vyāpan/ vyuhan karma of vyāna vāyu.
The end metabolites formed within the cell are removed through the process of exocytosis. The process is initiated by apāna vāyu which helps in excretion, mokshan, munchan karma at the level of cell.
Prof. Dr. Satyendra Narayan Ojha ,
MD (KC), Ph.D.
Director , Yashawant ayurveda college , Post graduate teaching and research center ,
Kodoli ,Panhala , Kolhapur..
My approach to Vaata with physiological perspective ; Cikitsā Sthāna Chapter 28 Vātavyādhi Cikitśītām..Verse 4 ;