Indriya

The term “indriya” refers to the sensory faculties (jnanendriya) (SAT-B.192) and motor faculties (karmendriya) (SAT-B.186) along with the internal system of perception of knowledge. Ayurveda describes the concept of indriya in a broader perspective than the structural presence of sense organs like eyes, ears, nose, skin, and tongue. Each sense has a capacity to connect with the consciousness and develop as a super sense in the presence of mind and soul. Intellect is also involved in the process of perception. This article describes the holistic concept of indriya and its contemporary utility in the preservation of health.

Contributors

Section/Chapter	Sharira / Indriya
Authors	Deole Y.S.1, Anagha S.1, Shilwant A.A.2
Reviewed by	Basisht G.1
Affiliations	1Charak Samhita Research, Training and Development Centre, I.P.G.T.& R.A., Jamnagar 2 Department of Kriya Sharir, G.J.Patel Institute of Ayurvedic Studies and Research, New Vallabh Vidyanagar, Anand, Gujarat, India
Correspondence email:	carakasamhita@gmail.com
Date of first publication:	April 21, 2021
DOI	In process

Etymology, derivation, and synonyms

The Sanskrit word Indriya means – “ that which is related to, or originated from ‘indra’ or created by the supreme power”. It means prana or vital life force. [Chakrapani on Cha.Sa.Indriya Sthana 1/1-2].

Indriya is the entity that works in the presence of mind and consciousness to perceive any knowledge or memories.

The word indriya is denoted by synonyms like hrushikam, vishayi, aksham, karanam, and grahanam. All these terms refer to the sensory and motor faculty along with their internal processing system.

Meanings in different contexts:

• The term indriya is also used to denote the semen virile (shukra). It also indicates any powerful act or bodily power.
• The presence of “indriya” is the criteria to determine the presence of consciousness (chetana) in a substance. [Cha. Sa. Sutra Sthana 1/48]
• The terms Indriya and Atma are used interchangeably in some contexts. [Cha. Sa. Sutra Sthana 8/18]
• The term indriya mainly refers to the sensory faculties. [Cha. Sa. Sutra Sthana 8/14] They are considered as the instruments (karana) for the knowledge in the form of direct perception (pratyaksha jnana). [Cha. Sa. Vimana Sthana 4/4]

Types or classification

Indriya are mainly classified into three categories:

a)Five sensory faculties (pancha jnanendriyani) - which include

• Auditory faculty (shrotrendriya)
• Tactile faculty(sparshanendriya)
• Visual faculty(chakshurindriya)
• Gustatory faculty(rasanendriya)
• Olfactory faculty(ghranendriya)[Cha.Sa.Sutra Sthana 8/8]

b)Five motor faculties (pancha karmendriyani)-which include

• Upper limbs and faculties regulating activities accomplished by it (hasta)
• Lower limbs and faculties regulating activities accomplished by it (pada)
• Rectum and associated faculties (guda)
• Primary and secondary sex organs with faculties controlling its activities (upastha)
• Tongue with peripheral speech apparatus and associated faculties (vagindriya)

[ Cha. Sa. Sharira Sthana 1/25-26]

c)Internal faculty (antah karana) - internal system of perception and cognition. It includes the inputs from the sensory faculties and their processing by the mind (manas), intellect (buddhi), and ego (ahamkara).

Mind (manas) is known as supreme faculty (atindriya) or dual faculty (ubhayendriya) which is having control over both sensory as well as motor faculties. [A.S.Sharira Sthana 5/44]

Formation of indriya

Panchchabhautika constitution

Indriya are formed from the five greater elements (panchamahabhuta). So, each of them has an affinity towards a particular sense of perception in an object which is having a similar elemental constitution. [Su. Sa. Sharira Sthana 1/15] E.g.: visual faculty (chakshurindriya) have an affinity towards the visual aspect of an object. So, it receives the signals about colour, size, and shape of an object and transmit this information to the respective higher center (chakshurindriya budhi)

• In embryonic development, indriya formation happens during the third month. [Cha.Sa.Sharira Sthana 4/11]

Special locations of Indriya

In the human body, each sensory faculty (indriya) is located in a particular area with a predominance of the particular mahabhuta. The only exception for this is tactile faculty (sparshanendriya) which is spread all over the body.

Pentad of senses (Indriya pancha-panchaka)

Indriya(Sense)	Mahabhuta	Object of perception (indriya artha)	Organ (indriya adhishthana)	Cognition (indriya buddhi)
Shrotrendriya(Auditory sense)	Akasha	Shabda (Sound)	Ear	Sense of hearing
Sparshanendriya(Tactile sense)	Vayu	Sparsha (touch)	Skin	Sense of tactile sensation, localization, discrimination
Chakshurindriya(Visual sense)	Agni	Rupa (sight)	Eye	Sense of vision
Rasanendriya(Gustatory sense)	Jala	Rasa (taste)	Tongue	Sense of gustation
Ghranendriya(Olfactory sense)	Prithvi	Gandha (smell)	Nose	Sense of olfaction

Difference between sense (indriya) and organ (indriya adhishtana)

To know physiological process of sensation, it is important to know the difference between sense and sense organs.

Sense (indriya):

It is a subtle instrumental form responsible for the manifestation of consciousness in a living being in the presence of mind (mana) and soul (atma). It communicates messages of the external world to the internal world in the physical body. It denotes the presence of vital force (prana) within a living body.

Sense organ (indriya adhisthana):

It is a structural, materialistic entity with particular dimensions. It is the physical abode to express the sensation.

Table: Difference between sense and sense organs

Sr. No	Sense (indriya)	Sense organ (indriya adhishtana)
1	Subtle form	Gross form (sthula)
2	It can be limitless	Structural entity with fixed dimensions
3	Perceives direct knowledge perception	Work as physical instrument to express
4	Primary contact with the source of knowledge	Secondary contact with the source of knowledge

Functioning of indriya

Process of perception of knowledge

As per ayurvedic perspectives, the process of cognition starts from within a person. The soul expresses will for the perception of knowledge through the mind. The mind then connects with the particular sense to fulfill the will. The sense searches and connects with the source to know about that particular object. The sense organ-specific intellect plays an important role in deciding good/bad, correct/incorrect things for the living being. Thus, the process of perception of knowledge is completed by coordination of sense organ, sense, intellect, mind, and soul. The knowledge gained by the soul is ‘self-knowledge’. It is stored in the memory and reminded whenever required.

The contemporary medical system emphasizes on stimulus and receptor theory. The external stimulus is received by the particular sense organ and conveyed to the brain. This is done through afferent neuronal pathways. The brain then reacts to that particular stimulus and expresses specific action through efferent neuronal pathways. However, this system seems to be partial in the absence of consciousness, which connects the sense to the sense object.

The five senses and their subtlest physical presence in the body can be presented in view of contemporary medical knowledge as below:

Table: Sense organs and their physical centers in body

Sr. No	Five senses (Indriya)	Five sense material (Indriya dravya)	Five sense organs (Indriya adhishthana)	Five sense objects (Indriya artha)	Five sense perception (Indriya buddhi)
1	Auditory sense (shrotrendriya)	Auditory receptors	Auditory area in brain(Area no. 21,22)	Organ of Cortii	Hearing
2	Tactile sense (sparshanendriya)	Tactile receptors	Somesthetic & Somesthetic Association area in brain(Area no. 1,2,3, 5&7)	Merkel’s disc, Meissner’s corpuscle, Free nerve endings	Tactile Sensation, Localization, Discrimination
3	Visual sense (chakshurendriya)	Photo -sensitive receptors	Primary Visual & Visual Association area in the brain (Area no. 17,18,19)	Rods & Cones	Vision
4	Gustatory sense (rasanendriya)	Gustatory receptors	Gustatory area in brain(Area no. 43)	Type III Gustatory cells with Papillae of Taste buds	Gustation
5	Olfactory sense (ghranendriya)	Olfactory receptors	Olfactory area in brain(Area no. 28)	Type I Olfactory cells	Olfaction

Motor organs (karmendriya)

The motor organs are equally important to perform activities and communication. These organs play role in expressing inner feelings to outer world. The following table shows motor organs and their functions.

Table: Motor organs (karmendriya) and their functions

Sr.No	Name of the motor organ	Body part or organ	Related controlling area in the brain	Activity
1	Speech (vagendriya)	Tongue, receptors at Peripheral Speech apparatus (Larynx with Vocal cords)	Broca’s area (area no. 44, 45), central speech apparatus (sensory & motor areas for speech)	Phonation
2	Giving (pani/hasta)	Hands, receptors at Upper extremity	Primary & premotor area(area no. 4, 4s, 6a, 6b), Areas of spino cerebellum & motor cerebral cortex	Neuromuscular coordination to give, receive, grasp,hold
3	Moving (pada)	Legs, receptors at Lower extremity	Primary & premotor area(area no. 4, 4s, 6a, 6b), Areas of spino cerebellum& motor cerebral cortex	Neuromuscular coordination for locomotion
4	Excretion (payu)	Rectum & the anal canal, receptors	Defecation reflex, Sacral nerves parasympathetic system	Excretion
5	Reproduction (upastha)	Sex organs and genitalia, receptors	Association area, Hypothalamus, Limbic system, Centre of arousal in Hypothalamus,Limbic system	Satisfaction, pleasure, reproduction

Similarity of receptor theory with indriya

Receptors are specialized materialistic structural interfaces made up of proteins. They have the ability to receive and transduce the signals received. This ability to transform and convert any form of energy into electrical energy makes the receptor behave as ‘biological transducers’. These can get saturated due to a finite number of binding sites. They have a high affinity towards respective ligands within physiological limits and concentrations. The impulse generated by receptors is further carried to higher centers situated in the brain and spinal cord to analyze and interpret the stimulus. This conduction of impulse on reaching the brain may either have or do not have a conscious perception of knowledge.

Receptors are basically sensitized structures or cells, that carry a specialized set of functions such as – can induce cell growth, division, and death; regulate cell permeability; regulates cell-binding; cell signaling, immune responses, and many more activities.

The receptors have properties of excitability, specificity, discrimination, and conductivity.

The above observations and discussion indicate striking similarities between the mechanism of indriya and receptors. The processes of acquiring knowledge, memory, and various physiological reactions can be seen in terms of indriya and receptor theory. The existence, structural modifications, and functional responsibilities of receptors can be justified by deeper perspectives. The excitability of receptors is manifested due to the presence of a state of consciousness (chetana adhishtana bhutam). The specificity of receptors and discrimination ability is due to a similar elemental constitution (samana / tulya yonitva). The conductivity of impulses through receptors reflects balanced and efficient nervous as well as endocrinal control over all the structures (samayogvahi). Thus, the properties of receptors befit into the mechanisms of perception of knowledge described in Ayurveda. However, this correlation needs more research to establish its utility in the treatment of diseases.

Importance in examination of patients

Indriya are the means of direct observation. (pratyaksha jnana) [Cha. Sa. Vimana Sthana 4/4], [Cha. Sa. Vimana Sthana 8/39] They are the tools that provide information to the physician about the health condition of a person. Therefore, a physician shall develop his senses to access the knowledge about patient and diseases.

The physician should use his five senses for examining the patient, diagnosis of disease, and elicit the features of the morbidity in the patient. [Su. Sa. Sutra Sthana 10/5]

E.g.:- size, shape, colour, etc. of swelling, colour, and nature of discharge from a wound are directly observed through visual faculty (chakshrurindriya).

Different sounds produced in the body like heartbeats, bowel sounds, the sound produced from joints, etc. are assessed using auditory faculty (shrotrendriya). [Cha. Sa. Vimana Sthana 4/7]

Diagnosis of diseases of indriya

The vitiated dosha affecting indriya can result in two types of pathology.

a)Mild or temporary damage (upatapa)

b)Complete and permanent damage (upaghata) [Cha. Sa. Sutra Sthana 28/20]

Weakness of indriya (indriya daurbalya)

The indriya become weak and less efficient due to abnormal increase of pitta dosha and decrease of vata and kapha dosha. [Cha. Sa. Sutra Sthana 17/60], [Su. Sa. Sutra Sthana 15 /13].The weakness may be either due to anatomical abnormality of the structural abode of these faculties or the functional abnormality in their controlling system. [Dalhana, Su. Sa. Sutra Sthana 15 /13]. The important cause of this condition is the consumption of incompatible foods (viruddha ahara). [Su. Sa. Sutra Sthana 20/19]. Studies have shown that dietary intake of green leafy vegetables, glycaemic index, and omega-3 fatty acid, as well as overall dietary pattern, can influence the risk factors of visual impairment. Low intakes of fat and protein have been associated with hearing discomfort.

Complete functional loss of indriya

When abnormally increased vata dosha affects the sensory faculties, they have a total loss of function (indriya vadha).[Cha.Sa.Chikitsa Sthana 28/29], [Su. Sa. Nidana Sthana 1/24]

When the total loss of senses (indriya nasha) is associated with any disease condition, it indicates the bad prognosis of the disease. [Cha.Sa.Sutra Sthana 10/20]

• Loss of function of sensory faculties (indriya nasha) is mentioned as a diagnostic feature in severe jwara.[Cha.Sa.Chikitsa Sthana 3/51]
• When the poison (visha) gets accumulated in the large intestine (pakwashaya), it produces disorders in the functioning of sensory faculties. [Su. Sa. Kalpa Sthana 1/42]
• Excessive administration of nasal errhines (nasya) results in dysfunction of sensory faculties. [Su. Sa. Chikitsa Sthana 40/ 40]
• In diseases due to excessive nourishment (santarpanottha vyadhi), due to aggravation of kapha dosha, diminished functioning of sensory faculties is seen. [Cha. Sa. Sutra Sthana 23/17]It is advised to perform therapeutic emesis (vamana) in case of kapha predominant fever (jwara) for correcting the functions of sensory faculties. [ Su. Sa. Uttara Tantra 39/129]

Improper indulgence in sensory and motor activities (asatmya indriyartha samyoga) : Improper, less or excess indulgence in sensory and motor activities is an important fundamental cause of any disease. [Cha. Sa. Sutra Sthana 8/15] The diseases related to indriya (aindriyaka vyadhi) are caused by non – utilization (ayoga), excessive utilization (atiyoga) and malpractice (mithya yoga) of sense or motor faculties. [ Cha. Sa. Sharira Sthana 1/128]

Effect of ageing on indriya

The power of sensory and motor faculties decreases with age. It is evident that after the age of forty years, the power starts decreasing gradually and it becomes more evident after age of seventy years. [Su. Sa. Sutra Sthana 35/29] Rasayana (rejuvenation) therapies shall be started well in advance at younger age to prevent this loss due to ageing. In a research study, it is found that an increase in the threshold for odour detection, lower perceived odour intensity, and a decreased ability to identify food-related odours occur in old age. Current research suggests that some nutritional deficiencies (e.g. zinc) are associated with taste disturbances in older individuals.

Preservation of health of indriya and management of disease

Daily regimen: Various procedures are included in the daily regimen (dinacharya) to preserve the health of indriya and manage diseases if they occur. [Cha.Sa. Sutra Sthana 5,6] The main objective of observing code of conduct (sadvritta) includes control over sense organs. [Cha.Sa. Sutra Sthana 8/18] The following table summarizes local procedures that help in this regard. Table: Procedures for prevention and management of diseases related to sense and motor organs Sense organs Local procedures Eyes Application of collyrium (anjana), local instillation of liquid medicines(ashchyotana), application of medicines in the form of paste on external surface of eye lid (bidalaka), irrigation with liquids (prakshalana), filling with medicated ghee preparations (tarpana), filling with specially extracted juice of medicinal plants (putapaka) Ear Filling with oil (karna poorana), fumigation (karna dhoopana) Nose Nasal errhines (nasya), Inhalation of medicated smoke (dhoomapana) Tongue Filling of oral cavity with oil or medicated liquids (kavala and gandoosha) Skin, Hands, legs Massage, exercise in proper quantity Speech Observing moral code of conduct, restraining from improper verbal communication Rectum and anal canal Non suppression of defecation urge, therapeutic enema (basti) Sex organs Non suppression of urge of micturition, ejaculation, therapeutic enema (basti), therapeutic enema through urinary canal and vagina (uttara basti)

Diet and beverages: Among dietary factors, the sweet taste (madhura rasa) is mentioned as the one which is pleasing and nourishing to all the sensory faculties. [Cha. Sa. Sutra Sthana 26/43], [Su. Sa. Sutra Sthana 42/10] Researches have shown the evidences that sweet taste receptors are ubiquitous throughout the body, including in the gastrointestinal tract as well as the hypothalamus. The fermented preparations especially those prepared from sugarcane has the property to enhance the efficiency of sensory faculties. [Su. Sa. Sutra Sthana 42/10], [Su. Sa. Sutra Sthana 45/ 183] Various studies have established that self-generated alcohol directly activates gustatory receptor and central neural substrates for sweet taste. Researchers have found the efficacy of ethanol to directly and immediately stimulate complex chemosensory circuits linked to motivationally-relevant limbic and cortical areas. Evidence suggests that meat and seafood consumption could potentially protect against hearing loss. Physical exercise: Walking for a comfortable distance in a particular manner(chamkramana)is also good for all sensory faculties. [Su. Sa. Chikitsa Sthana 24/80]. Recent researches also describe the functional roles of sense organs in the control of locomotion. A cross-sectional study (n = 22,804) revealed that high physical activity levels are associated with fewer visual impairments. High physical activity levels are also associated with better sensitivity to tastes.

More information

1. Indriyopakramaniya Adhyaya
2. Indriya Sthana