“Principles of Physiology in Ayurveda (Part 3- circulation)”
This is a transcript prepared by Dr. Varsha More
based on the lecture available at Ayurvedic Principles of Human Physiology
पचत्यन्नं विभजते सारकिट्टौ पृथक् तथा|
तत्रस्थमेव पित्तानां शेषाणामप्यनुग्रहम्|
करोति बलदानेन पाचकं नाम तत्स्मृतम्||
(A. H. Su 12/10, 11, 12)
The division of food into ‘Sara’ and ‘Kitta’and the major portion of digestion occurs in the small intestine. ‘Sara’ is the nutritive portions that get absorbed and the non-absorbable part i.e Kitta gets excreted. This happened with help of ‘Pachak Pitta’. Though made up of five basic elements, it is dominant in the fire principle, so it is devoid of fluidity and is called ‘Jatharagni’. The term Sara has been discussed in the fourteen chapters of Sutrasthan of Sushruta Samhita.
तत्र पाञ्चभौतिकस्य चतुर्विधस्य षड्रसस्य द्विविधवीर्यस्याष्टविधवीर्यस्य वाऽनेकगुणस्योपयुक्तस्याहारस्य सम्यक्परिणतस्य यस्तेजोभूतः सारः परमसूक्ष्मः स `रसः’ इत्युच्यते, तस्य हृदयं स्थानं|(Su .Sutra14/3)
At the beginning of the above shloka, Sushruta explains the different classifications of food. The classification is enumerated such as the one based on the Panchabhautika composition, another one is of four types based on the physical property of foodstuff. The third type of classification is based upon the prominent Rasa out of six tastes to which one or two Rasa could dominate. The fourth classification is based upon Veerya i.e Sheet Veerya and Ushna Veerya. Another classification is based on Ashtavidha Veerya, it could be further divided into eight subtypes. Based on the twenty types of Gunas(attributes), food can be further classified into several categories. Such type of food when get completely digested by the action of Agni, the resultant product formed is called Sara which is minute in nature. This minute portion formed after complete digestion of food is called ‘Rasa’. This minute portion named ‘Rasa’ after reaching the Hriday nourishes all other parts of the body.
How the Rasa does reaches to Hriday?
रसस्तु हृदयं याति समान मरुतेरितः|(Sharangdhar Purva Khand 6/8)
Samana Vata governs the re-entry of ‘Rasa ‘into the heart.
तेजोभूत परं सूक्ष्मः स रक्तरस उच्यते |(Atank Darpan on Madhav Nidan)
Sushruta simply mentioned that the minute product formed after the action of Agni is the only ‘Rasa’. While in the verse mentioned in Atank Darpan further clarifies that the product generated after the action of Agni contains Rasa as well as Rakta because both of them circulate together inside the body. The above explanations clarify that blood reaches the heart from the periphery and from there onwards it gets pumped to other parts of the body.
रसवहानां स्रोतसां हृदयं मूलं दश च धमन्यः|( Ch. Vi.5/7)
The root of Rasavah Srotas consists of a heart and ten great blood vessels attached to it. These ten great vessels may include great veins and big arteries that originate from the heart. Number ten should not be taken in a literal sense rather it should be understood as few blood vessels carry Rasa towards the periphery.
What is Rasa?
रसरूपो धातुः, किंवा रसतीति रसो द्रवधातुरुच्यते, तेन रुधिरादीनामपि द्रवाणां ग्रहणं भवति| Chakrapani on Ch.Chi 15/36
All the fluids that flow in the body can be termed as Rasa Dhatu. Whatever fluid present in the body can be termed as Rasa Dhatu provided that it circulates. Whenever the fluid flows into the body it comes under the term Rasa Dhatu.
Autonomic control of Heart:
How does this Rasa get pumped into peripheral parts of body?
व्यानेन रसधातुर्हि विक्षेपोचितकर्मणा|
युगपत् सर्वतोऽजस्रं देहे विक्षिप्यते सदा|(Ch. Chi 15/36)
The above verse explains that Vyan Vata is situated in the Hriday (heart) and it causes the propulsion of Rasa Dhatu from the Hriday. Today we know that the heart muscle has its intrinsic capacity to generate impulses and that is how the pumping is made possible. This intrinsic function of the heart is under the influence of the sympathetic and parasympathetic nervous systems. The entire autonomic nervous system controls the heart and the intrinsic ability of the heart to generate its impulses and to beat continuously. So all such controlling mechanisms can be included under the functions of Vyan Vata.
The continuous function of heart and the continuous flow of blood in the body could be interpreted by knowing certain adjectives that have been mentioned in the second line of the above shloka.
Meaning of adjectives used in the verse:
युगपत्- Rasa flows occurs simultaneously, सर्वतो – in the entire body,अजस्रं-everywhere in the body, सदा-continuously, विक्षिप्यते- forcefully
By the action of Vyan Vata flow of Rasa occurs simultaneously in the entire body, everywhere in the body continuously and forcefully. So one needs to understand that the physiology of circulation has been explained under Rasavah Srotas and not the Raktvah Srotas. Because Raktavah Srotas is mostly indicative of the ‘Hemopoietic System’, not the circulatory System’.
कृत्स्नदेहचरो व्यानो रससंवहनोद्यतः|(Su. Ni 1/17)
Vyan Vata moves through the entire body. The major function of Vyan Vata is to cause the movement of Rasa.
विण्मूत्रं आहारमलः सारः प्रागीरितो रसः|स तु व्यानेन विक्षिप्तः सर्वान् धातून् प्रतर्पयेत| Su.Su 46/526
Vita, Mutra, and Malarupi Vayu are three important waste products of Ahar. Saar is nothing but the Rasa that has been explained earlier. This understanding becomes important to understand the physiology of cardiovascular system and its relationship with digestion. Only the absorbable portion gets absorbed from the gut and it becomes the Rasa Dhatu. This Rasa enters the Hriday and then gets carried all over the body. Forceful expulsion of this Rasa because of the activity of Vyan. This Rasa afterward nourishes all the other Dhatus.
‘Circulation’ in General:
सन्तत्या भोज्यधातूनां परिवृत्तिस्तु चक्रवत्|Ch. Chi 15/21)
The analogy of a rotating wheel called ‘Chakra’ has been used to describe circulation. The nourishment of all the Dhatus takes place in a manner that is similar to a rotating wheel. The term circulation originates from a circle or circular movement which means something starts from some point and it returns to the same point after completing the circuit. Similarly, the analogy of Chakra captures the idea of circulation.
CVS: A complete circuit:
हृदो रसो निःसरति तस्मादेव च सर्वशः|
सिराभिर्हृदय चैति तस्मात् हृत्प्रभवः सिरा|| Bhel. Su 21
This reference from Bhel Samhita is very important because this is possibly one reference that explains the basics of the systemic circulation. It is said that this Rasa Dhatu is ejected out of Hridaya and from there onwards it moves all over the body. It once again reaches the Hridaya through the blood vessels known as Siras. Therefore Sira can be originated from Heart. This entire circulatory system is a closed circuit. It originates in the heart and ends up in the heart. The term Sira need not be always translated as vein because they originate in heart also. Here Siras can be considered as all type of blood vessels that originates in the heart and take the blood to all parts of the body and then carry the blood towards the heart.
Structure of Blood Vessels:
दश मूलसिरा हृत्स्थास्ताः सर्वं सर्वतो वपुः|
रसात्मकं वहन्त्योजस्तन्निबद्धं हि चेष्टितम्||
स्थूलमूलाः सुसूक्ष्माग्राः पत्ररेखाप्रतानवत्|
भिद्यन्ते तास्ततः सप्तशतन्यासां भवन्ति तु|| A.H. Sh.3/18,19
Ten major blood vessels that are attached to the Hriday run in the entire body. It carries the Oja which is circulating along with Rasa. It means that Ojas also circulates along with Rasa. In the previous references, it has been mentioned that Rakta also circulates along with Rasa. Therefore three important fractions that run in the cardiovascular system are Rasa, Rakta, and Ojas. Life is sustained because of Ojas that circulate along with Rasa. The site of origin of these blood vessels is comparatively gross, while tracing it towards the periphery they become minute and narrower. This appearance is like the reticular venation seen on the leaves. This is how these vessels divide and re-divide to become narrower. There are around 700 important blood vessels. The number 700 need not be important. It should not be taken in the literal sense. But it only indicates that there is a huge number of blood vessels.
Auto rhythmicity of Heart:
देहिनां हृदयं देहं सुखदुखःप्रकाशकम|तत् सङ्कोच विकासञच स्वतः कुर्यात् पुनः पुनः|| Nadivigyan
In human beings, Hriday is a good reflector of wellbeing and ill health of the body. This Hriday keeps on contracting and relaxing continuously on its own in repetitive fashion.
Heart -Anatomy and Functioning:
पुण्डरीकेण सदृशं हृदयं स्यादधोमुखम् |
जाग्रतस्तद्विकसति स्वपतश्च निमीलति || Su. Sh .4/32
Hriday looks like an inverted lotus bud. During day and night, it continuously undergoes contractions and relaxations. These repetitive actions seen on the Hriday occur in continuous fashion day and night.
Mean Flow Velocity of Blood:
स शब्दार्चिर्जलसन्तानवदणुना विशेषेणानुधावत्येवं शरीरं केवलम् |Su.Su 14/16
Rasa when pumped out of the Hriday it moves in a fashion similar to that of sound, flames of fire, and the waves of the water. Among the three analogies used here, Shabda travels with maximum velocity, and then comes the fire because the wildfire spreads dependent on the wind velocity. Wind velocity is less than the sound velocity. Water moves with minimum velocity among the three. Surprisingly the blood moves in the body in this way also. From the Aorta the velocity of blood can be observed that the mean flow velocity goes on getting reduced. In the big arteries, it is maximum. In smaller arteries and arterioles it is moderate and in the capillaries it is minimal. This is how the Rasa circulates inside the body.
Theories of Microcirculation:
किंवा रस एव रक्तं प्रथमं प्लावयति, तत्र च रक्तस्थानसम्बन्धाद्रक्तसादृश्यमनुभवति, रक्तं च रक्तसमानेनांशेन पोषयति; ततो रक्तमाप्लाव्य मांसमाप्लावयति, तत्रापि मांसपोषणं करोति, मांससादृश्यतामनुभवति; एवं उत्तरोत्तरधातून् रस एवाप्लावयति वर्धयति च; यथा केदारनिषिक्तं कुल्याजलं प्रत्यासन्नां केदारीं तर्पयित्वा क्रमेण केदारिकान्तराणि आप्लावयति| Chakrapani on Ch.Chi 15/16,17
The movement of Rasa and nourishment of other Dhatus is explained based on an analogy which is like the several canals that are used for irrigation of different fields of grains. Here water from the water reservoir is carried through the canal to irrigate the different fields. Similarly, Rasa also acts as a nutrient pool, and other Dhatus derive their nutrition only through this pool. First, Rasa nourishes Rakta and it becomes like Rakta. Then it moves on to other Dhatu. Thus Rasa itself nourishes all other Dhatus. Rasa represents a common nutrient pool from which all other Dhatus derive their nutrition. This is one important theory of circulation.
भिन्नैरेव मार्गैर्धातूनां पोषणं भवति; यथा खले उत्पतितानां कपोतानां भिन्नदिग्गामिनां स्वीयस्वीयमार्गेणैव गच्छतां गम्यदेशस्य प्रत्यासन्नविप्रकृष्टत्वादिभेदेन शीघ्रं चिरेण च गमनं भवति, तद्वत्| (Chakrapani on Ch.Chi15/16)
Another theory of nutrition is mentioned as Khale Kapot Nyay. The similes used here to explain this is that of pigeons that fly away from their nests to pick up the grains from the stored heaps of grains and pigeons return to their nests. So, the distance covered by them from their nests to the heaps of grain determines the nourishment of different pigeons and how fast they get nourishment. Likewise, tissues also get nutrients in the same way, based on the distance from the nutrient pool to the different tissues. So this is applicable in some instances of physiology. In the liver, the central vein is the vein that ultimately drains to become the hepatic vein. The branch of the hepatic artery branch and branch of the portal vein drains the blood into the sinusoids of the liver. The peripheral part of the lobule receives oxygen-rich blood because there is a mixture of arterial and venous blood. The peripheral parts of the lobule receive nutrient and oxygen-rich blood. While the blood reaches the central vein, the hepatocytes surrounding the central vein portion receive oxygen-poor blood. This kind of transport pattern may be observed in many other parts of the body also.