QS Study

Pathway of Hearing

The ear is a complex and very sensitive organ of the human body. The structure of the hearing system can be divided into four components for our expediency in remembering the parts and associating these parts with their function. These divisions are the:

  • outer ear
  • middle ear
  • inner ear
  • central auditory pathways.

The auditory pathway conveys the special sense of hearing. Pathway of hearing from collection of sound by auricle to the identification of the sound in the brain.

Fig: Pathway of Hearing

Pathway of hearing

  • Sounds waves collected by auricle,
  • External ear,
  • Sounds waves collected by auricle,
  • Internal ear (perilymph, endolymph),
  • Stimulation of hair cells of the organ of Corti,
  • Spiral ganglion (1st order neuron begins),
  • Cochlear division of the vestibulocochlear nerve,
  • Ventral and dorsal cochlear nuclei (2nd order neuron),
  • Most of the axons cross in the trapezoid body and terminate in opposite superior olivary nucleus, some are uncrossed,
  • Neurons of superior olivary nucleus form lateral lemniscus, (3rd order neuron)
  • Inferior colliculus (4th order neuron.),
  • Medial geniculate body (5th neuron),
  • Auditory radiation Primary auditory area (42) in the temporal lobe.