PATHWAYS OF EACH SENSE IN UNDERSTANDING OF ITS FUNCTIONAL ANATOMY

PATHWAYS OF EACH SENSE IN UNDERSTANDING OF ITS FUNCTIONAL ANATOMY

• The five Jnanendriyas (sense organs) in Ayurveda are responsible for perceiving the external world: Shrotra (ear), Tvak (skin), Chakshu (eye), Jihva (tongue), and Ghrana (nose).

• These are linked to their respective Indriya-Dravyas (anatomical structures), Indriya-Abhimani Devatas (cognitive control centers), and sensory pathways described in both Ayurvedic and modern anatomical frameworks.

SHROTRINDRIYA (ORGAN OF HEARING)
AYURVEDIC VIEW

• Shrotra is located in the Karna (ear) and functions through Akasha Mahabhuta.

• It is supported by Vyana Vata, Tarpaka Kapha and Aalochaka Pitta.

• Classical Reference:
  चक्षुः श्रोत्रं घ्राणं जिह्वा त्वक् च
  (Cha Sha 1/55 – five Jnanendriyas)

MODERN ANATOMY – AUDITORY PATHWAY (Ref: BD Chaurasia – Head and Neck)

• Begins at the organ of Corti in the cochlea (inner ear).

• Impulses carried by cochlear nerve, branch of CN VIII (Vestibulocochlear nerve).

• Synapses in cochlear nuclei (medulla).

• Crossed and uncrossed fibers ascend to inferior colliculus via lateral lemniscus.

• Relay at medial geniculate body of thalamus.

• Project to primary auditory cortex (Area 41 & 42) in temporal lobe.

CHAKSHURINDRIYA (ORGAN OF VISION)
AYURVEDIC VIEW

• Chakshu is located in Netra and functions through Teja Mahabhuta.

• Controlled by Aalochaka Pitta (particularly Drishti and Bhrajaka), and Tarpaka Kapha.

• Classical Reference:
  दृष्टिर्द्रष्टुर्दृशो दृष्टिः तस्यां संज्ञा प्रतिष्ठिता
  (Sha Sa U 4/5)

MODERN ANATOMY – VISUAL PATHWAY (Ref: BD Chaurasia – Head and Neck)

• Originates from photoreceptors in retina (rods & cones).

• Impulses relayed via bipolar and ganglion cells.

• Ganglion cell axons form optic nerve (CN II).

• Partial crossing at optic chiasma.

• Continue as optic tract to lateral geniculate body (LGB).

• Fibers form optic radiation to visual cortex (Area 17) in occipital lobe.

TVAGINDRIYA (ORGAN OF TOUCH)
AYURVEDIC VIEW

• Tvak (skin) perceives Sparsha (touch) through Vayu Mahabhuta.

• Vata is responsible for tactile perception, supported by Bhrajaka Pitta.

• Classical Reference:
  सर्वेन्द्रियाणां न त्वगस्ति निःश्रेयसकरणे
  (Cha Sha 1/72)

MODERN ANATOMY – TACTILE PATHWAY (Ref: BD Chaurasia – General Anatomy and CNS)

• Receptors: Meissner’s corpuscles, Merkel’s discs, Pacinian corpuscles, free nerve endings.

• First-order neurons: Cell bodies in dorsal root ganglia.

• Second-order neurons: Located in dorsal column nuclei (gracile and cuneate).

• Axons decussate and ascend via medial lemniscus.

• Relay at ventral posterolateral (VPL) nucleus of thalamus.

• Project to primary somatosensory cortex (Area 3,1,2) in parietal lobe.

JIHVENDRIYA (ORGAN OF TASTE)
AYURVEDIC VIEW

• Jihva perceives Rasa (taste) through Aap Mahabhuta.

• Function supported by Bodhaka Kapha and Aalochaka Pitta.

• Classical Reference:
  रसज्ञानेन जीह्वेयं ज्ञेया संज्ञावती सदा
  (Ashtanga Hridaya)

MODERN ANATOMY – GUSTATORY PATHWAY (Ref: BD Chaurasia – Head and Neck)

• Receptors in taste buds (fungiform, foliate, circumvallate papillae).

• Anterior 2/3 – Facial nerve (CN VII) via chorda tympani.

• Posterior 1/3 – Glossopharyngeal nerve (CN IX).

• Base of tongue & epiglottis – Vagus nerve (CN X).

• All synapse at nucleus of solitary tract in medulla.

• Second-order neurons ascend to VPM of thalamus.

• Project to gustatory cortex in insula and frontal operculum.

GHRAANENDRIYA (ORGAN OF SMELL)
AYURVEDIC VIEW

• Ghrana is the organ for perceiving Gandha (smell), associated with Prithvi Mahabhuta.

• Tarpaka Kapha maintains olfactory function.

• Classical Reference:
  घ्राणं गन्धविज्ञानं तत्र संज्ञा प्रतिष्ठिता
  (Sha Sa U 4/5)

MODERN ANATOMY – OLFACTORY PATHWAY (Ref: BD Chaurasia – Head and Neck)

• Begins at olfactory epithelium in nasal cavity.

• Bipolar receptor neurons form olfactory nerve fibers (CN I).

• Pass through cribriform plate to olfactory bulb.

• Synapse in glomeruli with mitral & tufted cells.

• Project via olfactory tract to primary olfactory cortex (piriform cortex, amygdala, entorhinal cortex) without thalamic relay.

SUMMARY TABLE OF SENSORY PATHWAYS