System
By: Brooklynne Harris
Scenario
A loud crashing sound causes everyone in the room to quickly turn their heads toward the source of the noise. Describe the path of the signal through the human nervous system from initial stimulus of sound to the response of turning the head.
Crash and then turn of the head
The Journey
The loud sound that the person heard is the stimulus. In order to hear a sound, sound waves have to be generated and sent to the cochlea in the inner ear. From the cochlea, the soundwaves are processed then sent from the auditory nerve to the brain to collect more information. Soundwaves entering the ear
In the brain, the sound is sent to the brain’s inferior colliculus. The colliculus is basically an auditory pathway located in the midbrain. It has a major part in determining sound signals. The information in the colliculus is then sent to the thalamus where the auditory signal is registered. Thalamus & Inferior Colliculus
After the thalamus registers the signal, it sends the info to the auditory cortex which is able to determine the frequency of the sound. After this is determined, the inferior colliculus is able to send messages that control reflexes. It reaches out to the motor neurons through an impulse that can control movements of the neck.
When the muscles receive the signal sent by the colliculus, they are able to contract and relax thus the person turning their head toward the noise that grabbed their attention.
To recap, the stimulus was the loud noise occurring and the response was the nervous system processing the sound and turning the neck to observe what the sound was.