Srotasa

The word ‘srotasa’ means a secretory channel for transportation and transformation of body constituents. Every body part has its own requirements for growth and nourishment. They are exposed to various environments. This need for various environments emphasizes on creating separate space for the development of different organs in the body. Fulfillment of basic needs as food and excretion is done simultaneously while performing the duties as a system by establishing a network between different organs. Different types of srotasa are described for major systems of the body. Major srotasa in the body are classified into eleven pairs by Sushrut [Su. Sa Sharira Sthana 9/12] and thirteen gross channels by Charak. [Cha. Sa. Vimana Sthana 5/6,7] Srotasa are the inner circulatory pathways of the body which provides area for physiological function of general entities of the body like dosha, tissue (dhatu), waste material (mala). It helps in transformation and circulation of essential nutrients that support the functional entities. The word ‘srotasa’ is understood as the active inner transport system of body-mind-soul. This chapter describes srotasa, its physiological and pathological aspects with importance in healthcare.

Contributors

Section/Chapter/topic	Concepts/Srotasa
Authors	Bhojani M. K. 1, Kabadwal Dipti1 Saini Deepika 1
Reviewer	Basisht G.2,
Editor	Deole Y.S.3
Affiliations	1 Department of Sharir Kriya, All India Institute of Ayurveda, New Delhi, India 2 Rheumatologist, Orlando, Florida, U.S.A. 3 Department of Kayachikitsa, G. J. Patel Institute of Ayurvedic Studies and Research, New Vallabh Vidyanagar, Gujarat, India
Correspondence emails	meera.samhita@aiia.gov.in, carakasamhita@gmail.com
Publisher	Charak Samhita Research, Training and Development Centre, I.T.R.A., Jamnagar, India
Date of publication:	April 07, 2023
DOI	10.47468/CSNE.2023.e01.s09.136

Etymology

The word srotasa is derived from the root (moola) “sravana” meaning to exude, to ooze, to flow of nourishing materials [ Cha. Sa. Sutra Sthana 30/12]. Literal meaning of srotas is “kha” or empty space, mainly they are considered as tracts, pathways, passages, artery, vein, nerve etc. [Cha. Sa. Vimana Sthana 5/9].

Definition

The human body is majorly made up of innumerable channels that are responsible for the transportation of various materials in the body. At the same time nourishing seven dhatus. [Cha. Sa. Vimana Sthana 5/3].

• “Sravanata srotansi” [Cha. Sa. Sutra Sthana 30/12]: The pathways that are helpful in the flow of nutritious substances in the body.
• “Sravanat rasadi srava pathatvaat srotansi” [Gangadhara commentary on Charak Samhita]: After the digestion of food, it is converted into essence (sara) & waste material (kitta part). The srotasa are pathways through which essence (sara bhaga) is transported in the body.
• The channels which carry the poshaka dhatu (the nourishing part of the dhatus) are called ‘srotasa’. [Chakrapani commentary on Charaka Samhita]
• The pathways which carry or transport all the significant materials like life elements (prana or rakta dhatu), four types of food, and all the dhatus are called ‘srotasa’. [Su. Sa Sharira Sthana 9/13]
• “Srotamayama hi sharirama” all the living being are comprised of various macro and micro channels.
• Generally, the word srotasa is understood as macro and micro channels steering in the living being.

Synonyms

Channels (srotasa) vein, venule (sira), artery, arteriole, capillary (dhamani), lymphatic ducts (rasayani), portal vein (rasavahini), nerve likewise radial nerve (nadi), passage (pantha), tracts like gastrointestinal tract (marga), body orifice like eyes, nose, ear, anus, vagina (sharira chhidra), closed passages (savrita), open passages (asavritni), sites like skin, lungs (sthana), habitation (niketa), spaces to be occupied by body constituents like liver and spleen (ashaya). [Cha. Sa. Vimana Sthana 5/9]

Formation

Formation of srotasa starts in the uterine life, vayu mahabhuta along with equilibrium state of agni mahabhuta demarcates the channels (srotasa). [Su. Sa Sharira Sthana 4/28] Similarly, when ovum is fertilized by sperm, genesis of zygote takes place. Further zygote divides into multiple cells in a process known as ‘cleavage’, triggering the beginning of embryonic diffraction. Later formation of different channels of the foetus takes place.

Classification

Srotasa are numerous in number because humans are a complex organism, and all body entities are made up of innumerable srotasa. [Cha. Sa. Vimana Sthana 5/3] Fundamentally, every cell of the body could be understood as srotasa. As per the ayurvedic classics, srotasa can be broadly classified into two types:

1. Sthula (Gross): They are further classified into two types:
1. Bahiramukha (external openings): Bahirmukha srotasa have external orifices on the body. Broadly they are nine in number [Su. Sa Sharira Sthana 5/6], two of them situated at the lower part of the body. Remaining seven are present in the upper part of the body. In females, three srotasa are mentioned below: [Su. Sa Sharira Sthana 5/10]

Male (9)	Female (12)
2 nostrils (nasa), external ear openings (karna), orbital opeings (akshi), mouth (mukh), external genitalia, anal orifice (guda)	9+ breast (stana), cervix or opeing of birth canal (yoni)

2. Internal openings (antarmukha): As per Acharya Charaka there are 13 main internal openings described [Ch. Sa Vimana Sthana 5/6] and Acharya Sushruta mentioned 22 internal openings [Su Sa Sharira Sthana 9/12]:

Srotasa	Root (moola) as per Charak Samhita	Root (moola) as per Sushruta Samhita
Pranavaha srotasa (respiratory channels and vitality system )	Heart (hridaya), gastroinstestinal tract (mahasrotasa)	Heart (hridaya), branches of aorta rasavahini dhamani
Ambuvaha srotasa (water and fluid system)	Soft palate (talu), gall bladder (kloma)	Soft palate (talu), gall bladder (kloma)
Annavaha srotasa (digestive system)	Stomach (amashaya), left lateral region of the abdomen (vamaparshva)	Stomach (amashaya), esophagus (annavahini dhamani)
Rasavaha srotasa (plasma and lymphatic system)	Heart (hridaya), branches of aorta (10 dhamani)	Heart (hridaya), the vessels or channel or terminal branches of the aorta that transport nutrition to various parts of the body (rasvahini dhamani)
Raktavaha srotasa (blood and vascular system)	Liver (yakrita), spleen (pleeha),	Liver (yakrita), spleen (pleeha), blood vessels (raktavahini dhamani)
Mamsavaha srotasa (channels maintaining muscle physiology)	Ligaments (snayu), 7 layers of skin (tvaka)	Ligaments (snayu), seven layers of skin (tvak), raktavahini dhamani
Medavaha srotasa (channels for lipid physiology)	Kidney (vrikka), omentum (vapavahana)	Lumbar region (kati), kidney (vrikka)
Asthivaha srotasa (channels for fibrocartilaginous system)	Bone or adipose tissue (meda), thigh (jaghana)	-
Majjavaha srotasa (channels for locomotor system)	Bones (asthi), joints (sandhi)	-
Shukravaha srotasa (reproductive channels)	Testicles (vrishana), the external genitalia (shepha)	Breast (stana), testicles (vrishana)
Artavavaha srotasa (channels for menstruation)	-	Womb (garbhashaya), endometrial arteries (artavavahini dhamani)
Mutravaha srotasa (channels for urinary system)	Urinary bladder (basti), groin region (vankshana)	Urinary bladder (basti), the external genitalia (medhra)
Purishavaha srotasa (defecatory channels)	Parts of the large intestine like cecum, rectum, sigmoid colon (pakvashaya), and anal canal (sthula guda)	Parts of large intestine (pakvashaya), anal canal (guda)
Swedavaha srotasa (perspiratory channels)	Fats (meda), hair follicles (lomakoopa)	-

These srotasa can be further divided into three subgroups for ease of understanding:

1. Three intake channels or channels leading to the interior: Annavaha, pranavaha & udakavaha srotasa. These act as channels for the ingestion and transportation of solids (food), liquid & gases on a broader account. Hence, these will be considered as digestive, respiratory and electrolyte balancing systems. These channels form the main links of the body's internal environment with the external environment. Further, these channels are more prone to disorders, as they serve as the first defence to the external foreign matter entering the body. These are the first sites of ama production.
2. Seven processor channels or channels of maintenance: These are dhatuvaha srotasa. These act as the processors of the body and maintain the equilibrium in their physiological states. In Ayurveda, dhatu is the body's structural unit that sustain sharira (body) and are responsible for its strength and immunity. These dhatuvaha channels provide the necessary nutrition for proper growth and development of the seven dhatus and the space for their transportation, digestion, and metabolism.These are the channels where ama is dislodged.
3. Three output channels or channels leading to the expulsion of metabolic wastes. These include purishavaha, mutravaha, and swedavaha srotasa (malavaha srotasa). These will act as channels for removing waste products and toxic substances. The metabolites formed during metabolism in dhatuvaha srotasa and three input channels are further transported to malavaha srotasa, according to ease of removal through different sites of elimination through the body, after being processed again for easy and smooth expulsion by natural orifices.
2. Sukshma (Micro channels): The small orifices or microscopic pores of the body are known as sukshma srotasa. The navel (nabhi) and tiny channels or orifice of the skin are understood as sukshma srotasa.

Morphological characters

• Colour: Colour of srotasa is similar to the respective tissue (dhatu) they carry.
• Size: Minute (anu) in size or can be visible under the microscope, (sthula) macro in size (we can see direct by the naked eye).
• Shape: Round (vritta) in shape, (dirgha) long, (pratana) tendril like [Ch. Sa Vimana Sthana 5/25].

Significance of srotasa

• The structural and functional unit of the body that transports essential components throughout the whole body.
• Synthesis of tissue (dhatu) in the body.
• Eliminating waste products from the body through urine, feces, sweat etc.
• Responsible for nutrition, protection, and equilibrium of the structural entities in the body.
• As per ancient science, srotasa are the supreme factor responsible for health and disease throughout life.
• Nadi is also one of the synonyms of srotasa, which signifies its function of control and transportation of sensory and motor reflexes in the whole body.
• Maintains homeostasis in various systems of the body. All the dosha, dhatu, and mala rely on srotasa for their development, conveyance, and expulsion.

Relation of srotasa with body tissue (dhatu)

The diet and regimen in the context of daily and seasonal routines which possess quality similar to dhatu are beneficial for respective dhatus and suitable for the srotasa. [Cha. Sa Vimana Sthana 5/23]

Causes of vitiation of srotasa

The food & lifestyle which have a quality similar to the doshas at the same time opposite to the qualities of dhatus are the prime factors for vitiation of srotasa. [Cha. Sa Vimana Sthana 5/23]

Characteristics of vitiation of srotasa

Vitiation of srotasa are classified into four categories as stated below: [Cha. Sa Vimana Sthana 5/24]

1. Excessive flow (atipravatti): Excessive formation or elimination of dosha, dhatu, mala e.g., excess urination (bahumutra) in prameha, diarrhea (atisara), hemorrhage, etc.
2. Accumulation or obstruction (sanga): Sanga means block in the passages, e.g., obstruction of sweda (sweating) in fever, obstruction of vata dosha in gulma disease, obstruction of piita dosha due to kapha in jaundice (shakhashrita kamala), delayed digestion (alasaka), digestive disorders (grahani), cold, constipation, etc.
3. Siragranthi: It denotes thickening or abnormal growth in the natural orifice of the body e.g., granthi, aneurysm in the artery, splenomegaly, varicose vein, tumors, etc.
4. Deviated flow (vimarga gamana): Diversion from natural passages e.g., movement of apana vata in udavarta, movement of food in the upward direction in vomiting (chhardi), abdominal diseases (udara roga), bleeding disorders (raktapitta), acute gastroenteritis (visuchika), fistula (bhagandara).

Clinical features of vitiation of each srotasa

Vitiation caused in the srotas will lead to manifestation as described below: [Cha. Sa Vimana Sthana 5/7] and [Su. Sa. Sharira Sthana 9/12]

S.no.	Srotasa	Clinical features
1	Pranavaha	Painful, irregular breathing, breathing with abnormal lung sounds (atisrishtamatibadham kupitamalpamalpamabhikshana va Sashabadamshoolamuchchawantam), forward bending of body (vinamana), syncope (moha), dizziness (bhrama), tremors (vepana) & (maranam) death
2	Udakavaha	Dryness of tongue,palate, lips,throat,kloma (jihvataluosshthakanthamklomashosha) polydypsia (ati pravriddham Pipaasa), death(maranam)
3	Annavaha	Anorexia (arochaka), indigestion avipaka), vomiting (chhardi), polydipsia (pipasa), blindness (andhya), flatulence (adhmana), pain in abdomen (shoola), death (maranam)
4	Rasavaha	Anorexia (aruchi), lack of interest in the food (ashradha), tastelessness (asyavairasya), nausea (hrillasa), heaviness in body (gaurav), fatigue (tandra), Fever (jwara), anemia (pandu), darkness in front of the eyes (tama), malnutrition (krishangata), premature aging (palita), loss of libido (klaibya), death (maranam)
5	Raktavaha	Skin disorder (twak vikara ), like melasma (vyanga), obstinate skin diseases (kushtha), ringwarm or tines (dadru), bleeding from different part of the body (raktapitta), Menorrhagia (asrigdara), anal & urogenital abscesses (gudamedrasyapaaka), jaundice (kamala), vitiligo (shvitra), fever (jwara), anemia (pandutva), conjunctivitis.
6	Mamsavaha	Granuloma (adhimansa), tumour (arbuda), adenoids (galashaluka), elongated uvula (gala shundika), gangrene (pootimansa), goitre (galaganda), cervical lymphadenitis (gandamalaemasciation), aneurysm (mamsa shosha), death (maranam).
7	Medavaha	Decreased life span (ayushohrasa), retarded movements/impaired body movements (Javoparodha), difficulty in sexual act (kricchra vyavayata), general debility (daurbalya), Bad odour of the body (daurgandhya) , excess sweating (swedabadha), excessive hunger (kshudhatimatra ), increased thirst, dryness (pipasatiyoga)
8	Asthivaha	Bony overgrowths (adhiasthi), extra teeth (adhidanta), odontitis (dantabheda), bone pain, splitting pain in bones (asthibheda, asthi shulam), discoloration (vivarnata), deformities of hair, bones, nails, and pain in bones and teeth (keshalomanakhashmakshrudosha)
9	Majjavaha	Pain in joints (parva ruka), confusion (bhrama), syncope (murchha), (arunshika), the interphalangeal joints appear big (Sthoola Mula of Parvas)
10	Shukravaha	Loss of libido (Klaibya), lack of erection (aharshanama), no progeny (Na cha jayte garbha), progeny will be deformed & a short life span (alpaaayuvirupama), abortion (garbhapata), miscarriage (garbhashrava)
11	Mutravaha	Polyuria (atisristham), scanty urination (atibaddhama), Obstructed urination (prakupitam), frequent urination (alpama alpama) viscous urination (bahalama), painful urination (sashoolam).
12	Purishvaha	Difficulty in excretion of stool (kruchchrata), faeces getting expelled in small quantities (alpama alpama) sounds during defecation (sa shabdama), painful excretion of faeces (sa shoolam), diarrhoea (ati dravam), hard stool (atigrathitama), excess formation of faeces (atibahu).
13	Swedavaha	Excessive (atiswedam) or no perspiration (aswedama), rougness (parushya) , horripilation (lomaharsha). excessive smoothness of skin ( atishlakshnata),
14	Artavavaha	Infertility (vandhyata), dyspareunia (maithuna asahishnuta), amennorhea (artava nasha).

Advanced diagnostic tools

Above stated clinical manifestation will be present if there is some kind of vitiation in the srotasa which can be diagnosed based on the features present alongwith several contemporary diagnostic tools that are described below:

1. Pranvaha srotasa: spirometry, ECG (electrocardiography), sputum analysis, lung function test, etc.
2. Udakavaha srotasa: esophageal manometry, chest X-ray, ECG(electrocardiography)
3. Annavaha srotasa: endoscopy, USG(ultrasonography) (whole abdomen),
4. Rasavaha srotasa: anthropometry,
5. Raktavaha srotasa: complete blood count, peripheral blood smear, blood culture, etc.
6. Mamsavaha srotasa: EMG(electromyography), biopsy, USG-doppler, etc.
7. Medavaha srotasa: lipid profile, hormone profile (mainly pituitary hormones), etc.
8. Majjavaha srotasa: bone marrow biopsy and aspiration
9. Asthivaha srotasa: X-ray, CT-Scan, MRI, DEXA-Scan, etc
10. Shukravaha srotasa: semen analysis, hormone profile, etc
11. Mutravaha srotasa: urine-routine & microscopic, ultrasonography (Kidney Ureter Bladder), etc.
12. Purishavaha srotasa: stool culture, USG (ultrasonography of abdomen and pelvis), proctoscopy, colonoscopy, etc.
13. Swedavaha srotasa: sweat test
14. Artavavaha srotasa: USG ((ultrasonography of abdomen and pelvis)), hormone profile

General principles of treatment of vitiation of srotasa

The features of srotodushti (vitiation of srotasa) should be first clinically identified by the physicians. After that, the treatment protocol is decided based on the principle of treatment of particular srotasa. The general line of treatment is similar to the line of treatment for selective diseases. [Ch. Sa Vimana Sthana 5/26-28].

Srotasa	Guidelines of treatment
Pranavaha srotasa	Treatment of respiratory disorders (shwasa) : In case of kapha pradhana: emesis (vamana), Purgation (virechana), healthy diet (pathya ashana), dhooma (medicated smoking) , linctus (leha) In case of vata pradhana: pacificatory (shamana) meat soup (mamsarasa) [Ch. Sa Chikitsa Sthana 17/88-90]
Annavaha srotasa	Treatment of ama dosha: deepana, pachana, massage (abhaynga), asthapana basti, anuvasana basti, snehapana [Ch. Sa Vimana Sthana 15/95,98]
Udakavaha srotasa	Treatment of polydipsia (trishna): Intake of water with honey, Or medicated water processed with herbs having properties like thin (tanu) light to digest (laghu), cold (sheeta), fragrant (sugandhi), and good taste (Surasa)[Ch. Sa Chikitsa Sthana 22/25,26]
Rasadi dhatuvaha srotasa	Treatment of dhatu pradoshaja vikara Rasavaha srotasa : langhana Raktavaha srotasa: virechana, upavasa and bloodletting, light diet. Mamsavaha srotasa: samshodhana, kshara karma, agnikarma Medovaha srotasa: by using various dravya having vata, kapha and meda nashaka properties, use of ruksha, ushna and tikshna dravya in basti. Asthivaha srotasa: panchakarma procedures, basti processed with milk (ksheera) and bitter (tikta aushadha). Majjavaha & shukravaha srotasa : Treated by madhura and tikta rasa pradhana anna, by vyayama and by vamana and virechana [Ch. Sa Sutra Sthana 28/25-28]
Mutravaha srotasa	Treatment of dysuria (mutrakrichhra), diuretics (mutrala dravya) [Ch. Sa Chikitsa Sthana 26/45,49,54,58]
Purishavaha srotasa	Treatment of diarrhea (atisara): basti, treatment is planned as per the stages of diarrhoea (avasthiki chikitsa) [Ch. Sa Chikitsa Sthana 19/19,123]
Swedavaha srotasa	Treatment of fever (jwara): fasting (langhana), steam (swedanam), time for natural recovery (kala), gruels (yavagu), bitter taste herbs for digestion (tikta rasa pachana) [Ch. Sa Chikitsa Sthana 3/140,42]

Clinical significance of srotasa

Clinical assessment of srotasa is done from the root level (mulasthana). It means the origin of strotasa is assessed through its functions. Therefore, vitiation of srotasa can be easily identified in various disorders related to the srotasa. Elaborated understanding of srotasa is necessary, because srotasa are the factors involved in the genesis of the entire body.
Pathogenesis or vitiation in the transport system leads to stagnation of unwanted things, depletion of essential nutrients, eredication of the body tissue and cells, and imbalance in the body, mind, and health. This leads to multiple diseases related to different channels of the body.
Srotasa is the inner transport or circulatory system of the body. These can be depicted on macroscopic (sthula) as well as microscopic (sukshama) level for the descriptions pertaining to the exchange of gases, transportation of various nutrients from the gastrointestinal tract to multiple parts of the body and elimination of waste products (kitta bhaga) like urine & feces, from the body. They are mainly structural and functional body units and carry essential nutrients, transmitting sensory and motor reflexes throughout the body. Sthula srotasa, along with their roots are emphasized for pathology & treatment. Srotasa play a prime role in understanding physiology, pathology, clinical medicine, etc.

Contemporary approach

As per contemporary physiology, cells are structural and functional body units. The group of cells form tissues. Organs and and different body systems are designated for specific functions. These systems carry their physiological functions and maintain homeostasis in body. The circulatory system, digestive system, endocrine system, exocrine system, immune system, muscular system, nervous system, urinary system, reproductive system, respiratory system, and skeletal system are examples of these systems.

Differences in fundamental concepts of ayurveda and conventional medicine

Conventional medicine progresses from first observing and understanding the structure of the cell, organs, tissues, system etc, and then projecting this understanding to explain how they might function in the entire body. In comparison, ayurveda progresses from observing the functioning of the body structures at first to building a conceptual understanding of how their network might be in the body. Ayurveda focuses on how functional understanding can help to know the structure in a better way. This is why some parts of body are named according to their function e.g. hridaya suggests functions of mind, anatomical heart, cardiac region, and head.

Physiological functions and medical approach to each one srotasa

• Annavaha srotasa is responsible for the nutritional supply since it covers esophagus & gastrointestinal tract.
• Pranavaha srotasa carries out the function of transportation of vayu since it moves through the heart & respiratory tract.
• Rasavaha & raktavaha srotasa transport rasa & rakta through heart, venous, arteriole circulatory system & other vessels.
• Swedavaha & medavaha srotasa performs detoxification since it covers subcutaneous fat tissue & sweat glands along with micropores of the skin.
• Manovaha & majjavaha srotasa are the causative factors for neuronal and sensory transportation.
• Shukravaha and artavavaha srotasa transport essential components throughout the reproductive and sexual organs.
• Purishavaha srotasa helps to transport fecal wastes and gaseous substances from the cecum, rectum, and intestine through anal orifice.
• Mutravaha srotasa helps with detoxification through the urinary tract.

Srotasa, receptors and membrane biology

This concept of srotasa supports the latest descriptions in contemporary science, such as receptor theory in terms of their specificity and membrane biology. The srotas play a major role in pathophysiology and pharmacotherapeutics. Understanding the concept of srotasa allows Vaidya to make decisions accurately regarding treatment and prognosis.

Future scope

It is necessary to probe into this important conventional concept scientifically. It may be significant to tackle comparative studies with the modern sciences' knowledge about membrane biology and systemic endothelial system. The concept of srotasa in  ayurveda is a large area of molecular biology research. Vitiation of srotasa is the major cause of pathology in any disease. There is a requirement for clinical and molecular research on the nature of vitiation of srotasa occurring in different clinical situations to develop preventive and treatment modalities on the lines of purification therapies.

Current researches

1. Review on the concept of srotas: Srotasa acts as the inner transport system of the body. These macro, micro level channels also include all range of structural and functional units designed to carry specific materials, molecules, messages, impulses, emotions, and thoughts and are typical for the substances they transport. The concept of receptor theory and their specificity and membrane biology is also indicated by the functional physiology of srotamsi, which has importance from the point of view of pathophysiology and pharmacophysiology..
2. Critical evaluation of srotas and their clinical Significance: Srotasa plays an essential role in disease manifestation. Understanding the concept of srotasa and srotovaigunya are vital to prognosis and treatment.
3. Ayurveda literary research study on some important aspects of srotas: This study mainly focuses on understanding the srotas regarding microcirculation and exploration of minute aspects of microchannels.
4. Critical appraisal of doshavaha srotas: The study is based on the various synonyms described in classical texts, focusing on the sira (vein) and further divided into three categories like the division of sira as vatavaha, pittavaha, kaphavaha & sarvavaha srotas. It makes it easier to understand srotas in the context of tridosha for better and more systematic treatment protocol.
5. A review article on concept of srotas with special emphasis on pranavaha srotas: This article emphasizes the pranavaha srotasa. It depicts the conductor and channeliser of prana (living force).

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