Chapter 16, Problem 19RQ

Summary Introduction

To review:

The auditory pathway to the cerebral cortex.

Introduction:

The ear contains mainly three parts, external ear, middle ear, and the internal ear. The ear consists of the pinna and the external acoustic meatus. The pinna collects the sound waves and sends it to the external acoustic meatus. From the various parts of the ear, the sound wave transmits to the auditory center, which lies in the cerebral cortex of the brain.

The cochlear hair cell receptors transmit auditory information to the cerebral cortex through the ascending auditory pathway. In the first step, impulses reach the cochlear nuclei in the medulla via the cochlear nerve. Then, it reaches the junction of the medulla and pons where superior olivary nuclei is present. It further ascends to the inferior colliculus through lateral lemniscus.

From the inferior colliculus, the auditory information reaches to the medial geniculate nucleus of the thalamus. Finally, conscious awareness of sound is generated when it reaches the primary auditory cortex by projecting axons of the thalamic neurons. Impulses from both ears reach each primary auditory cortex separately.