Changes

Systems biology studies biological systems by analyzing them (biologically, genetically, or chemically), by monitoring the gene, protein, and informational pathway responses, integrating these data and ultimately, formulating mathematical models that describe the structure of the system and its response to individual variations. Systems biology does not investigate individual genes or proteins one at a time. Rather, it investigates the behavior and relationships of all of the elements in a particular biological system while it is functioning. Thus, the systems biology theory understands the importance of the constituent units of the body as well as their networking. (Timothy Galitski, 2001)<ref> Timothy Galitski, and Leroy Hood. A new approach to decoding life: Systems Biology Annu. Rev. Genomics Hum. Genet. 2001; 2:343–72 </ref>  

Systems biology studies biological systems by analyzing them (biologically, genetically, or chemically), by monitoring the gene, protein, and informational pathway responses, integrating these data and ultimately, formulating mathematical models that describe the structure of the system and its response to individual variations. Systems biology does not investigate individual genes or proteins one at a time. Rather, it investigates the behavior and relationships of all of the elements in a particular biological system while it is functioning. Thus, the systems biology theory understands the importance of the constituent units of the body as well as their networking. (Timothy Galitski, 2001)<ref> Timothy Galitski, and Leroy Hood. A new approach to decoding life: Systems Biology Annu. Rev. Genomics Hum. Genet. 2001; 2:343–72 </ref>  

A simple example that can illustrate System biology approach is of sickle cell anemia. This disease is caused by a single point mutation at position 6 of the β-chain of hemoglobin, which changes hemoglobin’s oxygen affinity and promotes polymerization under hypoxic conditions. However, individuals with sickle cell disease can present with variety of symptoms which include hemolysis, inflammation, cell adhesion and end-organ ischemia-reperfusion injury and infarction. Patients also experience intermittent painful episodes due to acute vascular obstruction. (Mack KA) <ref> Mack KA, Kato GJ. Sickle cell disease and nitric oxide: A paradigm shift? Int J Biochem Cell Biol. 2006; 38(8): 1237–1243. </ref> There are many reasons for these different clinical manifestations, including the presence of other genes modifying the disease modifying genes (e.g., hemoglobin F). Hence, this example indicates that the knowledge of single gene is not sufficient to understand the disease. There is need to consider other genes or in other words other constituents of the body.  (verse 3)

A simple example that can illustrate System biology approach is of sickle cell anemia. This disease is caused by a single point mutation at position 6 of the β-chain of hemoglobin, which changes hemoglobin’s oxygen affinity and promotes polymerization under hypoxic conditions. However, individuals with sickle cell disease can present with variety of symptoms which include hemolysis, inflammation, cell adhesion and end-organ ischemia-reperfusion injury and infarction. Patients also experience intermittent painful episodes due to acute vascular obstruction. (Mack KA) <ref> Mack KA, Kato GJ. Sickle cell disease and nitric oxide: A paradigm shift? Int J Biochem Cell Biol. 2006; 38(8): 1237–1243. </ref> There are many reasons for these different clinical manifestations, including the presence of other genes modifying the disease modifying genes (e.g., hemoglobin F). Hence, this example indicates that the knowledge of single gene is not sufficient to understand the disease. There is need to consider other genes or in other words other constituents of the body.  [verse 3]

=== Definition of ''sharira'' and disequilibrium in body elements ===

=== Definition of ''sharira'' and disequilibrium in body elements ===

In the seventh chapter of this section, we would see that the average quantity of ''dhatu'' is described in terms of ''anjali pramana'' (a measurement by joining palms of both hands). In spite of the description of these quantities one has to depend on the signs and symptoms of aggravation and diminution of ''dhatu'' as they are not available directly for measurement. Therefore, the maximum increase of ''shukra'' which does not produce a disease should be considered as the limit of the normal range of this ''dhatu'' and ''vaishamya'' should be diagnosed when abnormal symptoms will get manifested.

In the seventh chapter of this section, we would see that the average quantity of ''dhatu'' is described in terms of ''anjali pramana'' (a measurement by joining palms of both hands). In spite of the description of these quantities one has to depend on the signs and symptoms of aggravation and diminution of ''dhatu'' as they are not available directly for measurement. Therefore, the maximum increase of ''shukra'' which does not produce a disease should be considered as the limit of the normal range of this ''dhatu'' and ''vaishamya'' should be diagnosed when abnormal symptoms will get manifested.

Some scholars opine that sometimes the increase or decrease can be physiological (''prakrita''). They cite the example (Cha. Su 17/45-46) that the diminution of ''kapha'' aggravates ''vata'' and further draws the ''pitta'' which is in its normal state from its site and makes it circulate through the body to produce pain in the sites of its circulation. In this case, even though the ''pitta dosha'' is in its normal state, it causes discomfort in the body because of external factors (''paratantra prakopa/ashayapakarsha gati'').  

Some scholars opine that sometimes the increase or decrease can be physiological (''prakrita''). They cite the example [Cha. Sa. [[Sutra Sthana]] 17/45-46] that the diminution of ''kapha'' aggravates ''vata'' and further draws the ''pitta'' which is in its normal state from its site and makes it circulate through the body to produce pain in the sites of its circulation. In this case, even though the ''pitta dosha'' is in its normal state, it causes discomfort in the body because of external factors (''paratantra prakopa/ashayapakarsha gati'').  

This statement is not convincing because in another verse of the same chapter (Cha. Su 17/62), the author has described three different states of ''dhatu'' viz. increase, decrease and normalcy along with their diagnostic criteria. In its normal state, a ''dhatu'' does not produce any kind of discomfort or destruction. Also, a disease is defined as the result of the imbalance of ''dhatus'' and the normal state of these ''dhatus'' is described to constitute the health. (Cha. Su 9/4)

This statement is not convincing because in another verse of the same chapter [Cha.Sa. [[Sutra Sthana]] 17/62], the author has described three different states of ''dhatu'' viz. increase, decrease and normalcy along with their diagnostic criteria. In its normal state, a ''dhatu'' does not produce any kind of discomfort or destruction. Also, a disease is defined as the result of the imbalance of ''dhatus'' and the normal state of these ''dhatus'' is described to constitute the health. [Cha.Sa. [[Sutra Sthana]] 9/4]

The correct understanding of the verse (Cha. Su 17/45-46) therefore should be that if the ''pitta'' in its normal state, when carried by the aggravated ''vata'', circulates in the body, and gets mixed up with the ''pitta'' of other places, and then actually there is an increase in local ''pitta'' of those places, this increased state of ''pitta'' is in fact responsible for the cause of symptoms/disease.

The correct understanding of the verse [Cha.Sa. [[Sutra Sthana]] 17/45-46] therefore should be that if the ''pitta'' in its normal state, when carried by the aggravated ''vata'', circulates in the body, and gets mixed up with the ''pitta'' of other places, and then actually there is an increase in local ''pitta'' of those places, this increased state of ''pitta'' is in fact responsible for the cause of symptoms/disease.

Even when ''dhatus'' are in their normal states before they come in contact with the aggravated ''dosha'', their equilibrium gets disturbed after the interaction with ''dosha''. The manifestation of diseases, therefore, is possible only when ''dhatu'' are either increased or decreased due to this interaction and the consequent imbalance.

Even when ''dhatus'' are in their normal states before they come in contact with the aggravated ''dosha'', their equilibrium gets disturbed after the interaction with ''dosha''. The manifestation of diseases, therefore, is possible only when ''dhatu'' are either increased or decreased due to this interaction and the consequent imbalance.

Medicines need to be used appropriately (''samayaka avacharyamana'') in terms of (dose, duration, concomitant medicine/vehicle etc.). The use of ''yukti pramana'' can help to understand the scope of ''samyaka'' in a given situation at a given point in time. These are the pharmacotherapeutics principles of clinical pharmacology in [[Ayurveda]].   

Medicines need to be used appropriately (''samayaka avacharyamana'') in terms of (dose, duration, concomitant medicine/vehicle etc.). The use of ''yukti pramana'' can help to understand the scope of ''samyaka'' in a given situation at a given point in time. These are the pharmacotherapeutics principles of clinical pharmacology in [[Ayurveda]].   

The major focus of administering therapies for the cure of diseases as well as maintenance of health is to bring about the balance of ''dhatu'' which results into alleviation of diseases. ''Rasayana'' therapy which is administered for promotion of the strength of a healthy individual is primarily aimed at maintaining the equilibrium of ''dhatu'' and further improving them qualitatively. So the ultimate objective of [[Ayurveda]] is to establish the equilibrium of ''dhatu''. (Ca.Su.1/53). In healthy persons, although ''dhatus'' are in a state of equilibrium, ''rasayana'' and ''vajikarana'' therapies are given to maintain this state of equilibrium. Even the selection of dietary articles should be done with this objective in mind.  

The major focus of administering therapies for the cure of diseases as well as maintenance of health is to bring about the balance of ''dhatu'' which results into alleviation of diseases. ''Rasayana'' therapy which is administered for promotion of the strength of a healthy individual is primarily aimed at maintaining the equilibrium of ''dhatu'' and further improving them qualitatively. So the ultimate objective of [[Ayurveda]] is to establish the equilibrium of ''dhatu''. [Cha.Sa. [[Sutra Sthana]]1/53]. In healthy persons, although ''dhatus'' are in a state of equilibrium, ''rasayana'' and ''vajikarana'' therapies are given to maintain this state of equilibrium. Even the selection of dietary articles should be done with this objective in mind.  

The term ''satmyasamadnyata'' means the food preparations which are consistently wholesome at all times and which exclude the preparations that are wholesome only when taken habitually (''abhyasa'') but not otherwise. The wholesomeness of substances is to be considered in terms of ''rasa'' and ''guna''.

The term ''satmyasamadnyata'' means the food preparations which are consistently wholesome at all times and which exclude the preparations that are wholesome only when taken habitually (''abhyasa'') but not otherwise. The wholesomeness of substances is to be considered in terms of ''rasa'' and ''guna''.

Consumption of food preparations dominated by one type of ''rasa'' may produce imbalance of ''dhatu'' and then it becomes necessary to counterbalance the changes by following regimens having opposite effects. For example, when a person eats food dominated by ''madhura'' (sweet) taste then ''kapha dosha'' gets aggravated and hence, he should follow regimens like exercise that produce opposite effects i.e. reduce ''kapha''. It is needless to say that even such regimens should not be taken in excess.(7)

Consumption of food preparations dominated by one type of ''rasa'' may produce imbalance of ''dhatu'' and then it becomes necessary to counterbalance the changes by following regimens having opposite effects. For example, when a person eats food dominated by ''madhura'' (sweet) taste then ''kapha dosha'' gets aggravated and hence, he should follow regimens like exercise that produce opposite effects i.e. reduce ''kapha''. It is needless to say that even such regimens should not be taken in excess.[verse 7]

=== Guidelines for sustaining equilibrium ===

=== Guidelines for sustaining equilibrium ===

The concept has been explained with an example of obese individuals. For them, activity contrary to their “usual” place would be to sleep in an arid zone, activity contrary to time would be to exercise in spring season, and activity contrary to their make up or constitution would be to exercise at late nights.

The concept has been explained with an example of obese individuals. For them, activity contrary to their “usual” place would be to sleep in an arid zone, activity contrary to time would be to exercise in spring season, and activity contrary to their make up or constitution would be to exercise at late nights.

The concept of indulging in food and activities contrary to the environmental conditions and constitutions of an individual is a part of ''swasthavritta vidhi''. This has been described in (Cha.Su. 7/50, Cha. Vi. 5/23 and Cha.Su.26/8). Interestingly, the ''samprapti'' (pathogenesis) of ''rajayakshma'' includes all the above mentioned conditions as etiological factors. It would be worth exploring whether compliance/adherence to ''swasthavritta vidhi'' can prevent development of ''rajayakshma''. (8)

The concept of indulging in food and activities contrary to the environmental conditions and constitutions of an individual is a part of ''swasthavritta vidhi''. This has been described in [Cha.Sa. [[Sutra Sthana]] 7/50], [Cha.Sa. [[Vimana Sthana]] 5/23] and [Cha.Sa. [[Sutra Sthana]] 26/8]. Interestingly, the ''samprapti'' (pathogenesis) of ''rajayakshma'' includes all the above mentioned conditions as etiological factors. It would be worth exploring whether compliance/adherence to ''swasthavritta vidhi'' can prevent development of ''rajayakshma''. [verse 8]

=== Increase and decrease in body elements ===

=== Increase and decrease in body elements ===

=== Effect of stress ===

=== Effect of stress ===

Acute stress elicits a burst of growth hormone secretion, but chronic exposure to stress such as is caused by psychosocial deprivation suppresses growth hormone secretion, resulting in failure to grow. Once the stress is removed, growth hormone secretion rapidly returns to normal and then there is a period of catch-up growth. Postnatal growth is affected by nutrition, socioeconomic factors, disease, urbanization, psychosocial stress, and physical activity. There is a complex interaction among these different factors, and periods of retardation can be compensated by ensuing catch-up growth if the adverse factors are remedied. (Henriette A,1993)<ref name=ref7/>Excellence of mind:

Acute stress elicits a burst of growth hormone secretion, but chronic exposure to stress such as is caused by psychosocial deprivation suppresses growth hormone secretion, resulting in failure to grow. Once the stress is removed, growth hormone secretion rapidly returns to normal and then there is a period of catch-up growth. Postnatal growth is affected by nutrition, socioeconomic factors, disease, urbanization, psychosocial stress, and physical activity. There is a complex interaction among these different factors, and periods of retardation can be compensated by ensuing catch-up growth if the adverse factors are remedied. (Henriette A,1993)<ref name=ref7/>

The sympathetic nervous system regulates the function of the immune system primarily via adrenergic neurotransmitters released through neuronal routes. Neuroendocrine regulation of immune function is essential for survival during stress or infection and to modulate immune responses in inflammatory disease. Glucocorticoids are the main effector end point of this neuroendocrine system and, through the glucocorticoid receptor, have multiple effects on immune cells and molecules.(Webster JI,2002)<ref> Webster JI, Tonelli L, Stenberg EM. Neuroendocrine Regulation of Immunity. Annual Review of Immunology. Vol. 20: 125-163.2002 </ref>. (13)

 

=== Excellence of mind ===

The sympathetic nervous system regulates the function of the immune system primarily via adrenergic neurotransmitters released through neuronal routes. Neuroendocrine regulation of immune function is essential for survival during stress or infection and to modulate immune responses in inflammatory disease. Glucocorticoids are the main effector end point of this neuroendocrine system and, through the glucocorticoid receptor, have multiple effects on immune cells and molecules.(Webster JI,2002)<ref> Webster JI, Tonelli L, Stenberg EM. Neuroendocrine Regulation of Immunity. Annual Review of Immunology. Vol. 20: 125-163.2002 </ref>. [verse 13]

=== Factors responsible for transformation of food ===

=== Factors responsible for transformation of food ===

''Ahara parinamakara bhava'' (factors responsible for the process of digestion) should be considered in both the ways i.e. ''prakrita'' and ''vikrita''. Food consumed in the appropriate manner (by considering ''ahara parinamakara bhava'') leads to the production of ''param sukshma ahara rasa'' which in turn leads to good health. Conversely, improperly formed ''ahara rasa'' may in turn become the cause for the production of various diseases.(15)

''Ahara parinamakara bhava'' (factors responsible for the process of digestion) should be considered in both the ways i.e. ''prakrita'' and ''vikrita''. Food consumed in the appropriate manner (by considering ''ahara parinamakara bhava'') leads to the production of ''param sukshma ahara rasa'' which in turn leads to good health. Conversely, improperly formed ''ahara rasa'' may in turn become the cause for the production of various diseases.[verse 15]

The ''ahara'' which has undergone the complete digestion process only is able to provide nutrition to the body. (Cha.chi 15/5). Improperly formed ''ahara rasa'' (not having undergone the proper digestion process) cannot do the nourishment of ''dhatu''. (16)

The ''ahara'' which has undergone the complete digestion process only is able to provide nutrition to the body. [Cha.Sa. [[Chikitsa Sthana]]15/5]. Improperly formed ''ahara rasa'' (not having undergone the proper digestion process) cannot do the nourishment of ''dhatu''. [verse 16]

=== Foetal development ===

=== Foetal development ===

According to contemporary science, it has been observed that after the formation of the zygote, the cells further divide and form into a ball of cells called blastocyst. Once this blastocyst reaches the uterus, it buries itself in the uterine wall. The blastocyst sticks tightly to the wall of the uterus and receives nourishment from the mother's blood. Further the embryonic cells multiply and start to take on specific functions. This is called differentiation. Blood cells, kidney cells, and nerve cells all develop. Simultaneously the brain, spinal cord, heart and gastrointestinal tract begin to develop. Further the arm, leg buds, cranial nerves, main vessels, lungs and other begin to develop. <ref> Cunningham FG, Leveno KJ, Bloom SL, et al. Fetal growth and development. In: Cunningham FG, Leveno KL, Bloom SL, et al, eds.Williams Obstetrics. </ref>  <ref> Ross MG, Ervin MG, Novak D. Placental and Fetal Physiology. In: Gabbe SG, Niebyl JR, Simpson JL, eds. Obstetrics: Normal and Problem Pregnancies. </ref>

According to contemporary science, it has been observed that after the formation of the zygote, the cells further divide and form into a ball of cells called blastocyst. Once this blastocyst reaches the uterus, it buries itself in the uterine wall. The blastocyst sticks tightly to the wall of the uterus and receives nourishment from the mother's blood. Further the embryonic cells multiply and start to take on specific functions. This is called differentiation. Blood cells, kidney cells, and nerve cells all develop. Simultaneously the brain, spinal cord, heart and gastrointestinal tract begin to develop. Further the arm, leg buds, cranial nerves, main vessels, lungs and other begin to develop. <ref> Cunningham FG, Leveno KJ, Bloom SL, et al. Fetal growth and development. In: Cunningham FG, Leveno KL, Bloom SL, et al, eds.Williams Obstetrics. </ref>  <ref> Ross MG, Ervin MG, Novak D. Placental and Fetal Physiology. In: Gabbe SG, Niebyl JR, Simpson JL, eds. Obstetrics: Normal and Problem Pregnancies. </ref>

Hence it may be appropriate to accept Dhanvantari’s view that all the organs start developing simultaneously. (21)

Hence it may be appropriate to accept Dhanvantari’s view that all the organs start developing simultaneously. [verse 21]

The presently accepted cephalopelvic position correlates well to the position of the foetus explained in the classics.(22)

The presently accepted cephalopelvic position correlates well to the position of the foetus explained in the classics.[verse 22]

Modern embryology supports that the fetal blood flows through villi in which the capillaries are covered only by fetal tissue. It bathes directly in the intervillous space in a pool of flowing maternal blood. The transfer, processing and synthesis of nutrients under the influence of maternal, fetal and placental hormones is carried by various parts of the placenta through several modes. Lipid soluble molecules such as respiratory gases, anesthetic agents, several drugs and unconjugated bilirubin cross easily by penetrating the cell membrane.  Small water soluble molecules such as urea and water also cross easily by diffusion or osmosis. A specific carrier molecule facilitate transfer of glucose. Specific carrier mediated processes are carried to transport most amino acids, calcium, potassium and phosphorous from mother to fetus. This consumes energy leads to active transport leading to higher concentration in fetal than in maternal plasma. IgG, iron and vitamin B12 are transported by means of a receptor mediated mechanism into the fetal circulation. Any changes in the rate of blood flow hardly affect permeability of lipid insoluble substances. Their passage is ‘membrane limited’ and control of their transfer is largely by a change in placental tissue carrier mechanisms. Large increases in placental blood flow as gestation proceeds are important so that the transport of respiratory gases can be increased to meet the needs of the growing fetus. This mechanism of transport is similar to ''upasneha'' and ''upasweda nyaya'' described in this chapter. <ref> Mother and Child Nutrition in the Tropics and Subtropics. Nutrition in Pregnancy and Growth of the Foetus. Chapter 4:pp 104-105 </ref> (23)

Modern embryology supports that the fetal blood flows through villi in which the capillaries are covered only by fetal tissue. It bathes directly in the intervillous space in a pool of flowing maternal blood. The transfer, processing and synthesis of nutrients under the influence of maternal, fetal and placental hormones is carried by various parts of the placenta through several modes. Lipid soluble molecules such as respiratory gases, anesthetic agents, several drugs and unconjugated bilirubin cross easily by penetrating the cell membrane.  Small water soluble molecules such as urea and water also cross easily by diffusion or osmosis. A specific carrier molecule facilitate transfer of glucose. Specific carrier mediated processes are carried to transport most amino acids, calcium, potassium and phosphorous from mother to fetus. This consumes energy leads to active transport leading to higher concentration in fetal than in maternal plasma. IgG, iron and vitamin B12 are transported by means of a receptor mediated mechanism into the fetal circulation. Any changes in the rate of blood flow hardly affect permeability of lipid insoluble substances. Their passage is ‘membrane limited’ and control of their transfer is largely by a change in placental tissue carrier mechanisms. Large increases in placental blood flow as gestation proceeds are important so that the transport of respiratory gases can be increased to meet the needs of the growing fetus. This mechanism of transport is similar to ''upasneha'' and ''upasweda nyaya'' described in this chapter. <ref> Mother and Child Nutrition in the Tropics and Subtropics. Nutrition in Pregnancy and Growth of the Foetus. Chapter 4:pp 104-105 </ref> [verse 23]

''Kalayoga'' is interpreted as ‘attainment of proper time’ e.g. development of body in adolescence (seventeen years of age and onwards). The seasons of the year are also considered. ''Swabhava'' means the invisible factor of nature. ''Avighata'' is the absence of inhibiting factors such as excessive sexual act, mental stress etc. ''Avighata'' to ''ahara'' and thus interprets in restricted sense as ‘non-antagonism of dietary factors’. (12)

''Kalayoga'' is interpreted as ‘attainment of proper time’ e.g. development of body in adolescence (seventeen years of age and onwards). The seasons of the year are also considered. ''Swabhava'' means the invisible factor of nature. ''Avighata'' is the absence of inhibiting factors such as excessive sexual act, mental stress etc. ''Avighata'' to ''ahara'' and thus interprets in restricted sense as ‘non-antagonism of dietary factors’. [verse 12 ]

Inhabitants of certain places like Sindh are strong by nature. This is because of the specific characteristics of those places. Birth in such countries makes the individuals strong. Similarly, in certain seasons like ''hemanta'' and ''shishira'', people generally gain strength, and birth in such seasons makes the individual strong. Moderate climate when there is no excess heat and cold and which is pleasant also promotes the strength of the individual.  

Inhabitants of certain places like Sindh are strong by nature. This is because of the specific characteristics of those places. Birth in such countries makes the individuals strong. Similarly, in certain seasons like ''hemanta'' and ''shishira'', people generally gain strength, and birth in such seasons makes the individual strong. Moderate climate when there is no excess heat and cold and which is pleasant also promotes the strength of the individual.  

The progeny of parents having no abnormality or having the excellence of ''beeja'' and ''kshetra'' is endowed with strength. Here ''beeja'' means the healthy sperm and ovum, while ''kshetra'' means the uterus where implantation and further growth of embryo takes place.  

The progeny of parents having no abnormality or having the excellence of ''beeja'' and ''kshetra'' is endowed with strength. Here ''beeja'' means the healthy sperm and ovum, while ''kshetra'' means the uterus where implantation and further growth of embryo takes place.  

Mind also has control over the body. (Cha.Sha. 4/ 36). If the individual is mentally strong, then his body will also be quite strong. Some people are also endowed with a strong physique because of their virtuous actions in their past lives. Habitual performance of exercise is also known to promote the strength of an individual.(13)

Mind also has control over the body. [Cha.Sa. [[Sharira Sthana]] 4/ 36]. If the individual is mentally strong, then his body will also be quite strong. Some people are also endowed with a strong physique because of their virtuous actions in their past lives. Habitual performance of exercise is also known to promote the strength of an individual.[verse 13]

Eight factors to be kept in mind for the administration of food in appropriate manner are described in first chapter of [[Vimana Sthana]](Cha.Vi. 1/21-22). Balanced use of these eight factors regarding diet is considered as ''samayoga''. (14)

Eight factors to be kept in mind for the administration of food in appropriate manner are described in first chapter of [[Vimana Sthana]][ [Cha.Sa. [[Vimana Sthana]] 1/21-22]. Balanced use of these eight factors regarding diet is considered as ''samayoga''. [verse 14]

''Ushma'' takes part directly in the digestion of food and the remaining factors take part indirectly. ''Vata'' transports food to the site of ''agni'' to facilitate and stimulate digestion (Cha.Chi.15/6,17). (Cha.Chi.15/17). Apart from this, specific time is required to complete the digestive process. The detail process of digestion and metabolism is described in fifteenth chapter of [[Chikitsa Sthana]](Cha. Chi.15/6-11).(15)

''Ushma'' takes part directly in the digestion of food and the remaining factors take part indirectly. ''Vata'' transports food to the site of ''agni'' to facilitate and stimulate digestion [Cha.Sa.[[Chikitsa Sthana]] 15/6,17]. Apart from this, specific time is required to complete the digestive process. The detail process of digestion and metabolism is described in fifteenth chapter of [[Chikitsa Sthana]] [Cha.Sa.[[Chikitsa Sthana]] 15/6-11]. [verse 15]

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