page_title: Tensor tympani muscle
section_title: Involuntary control (tympanic reflex)
hierarchical_section_title: Tensor tympani muscle / Function / Involuntary control (tympanic reflex)
caption_attribution_description: English: The eardrum is excited with a 500 Hz probe tone that sets it into motion. A 1000 Hz elicitor tone is presented for 0.5 seconds (Blue bar indicates the presentation of the elicitor) and causes the acoustic reflex to activate. When the elicitor is turned off, the muscles of the middle ear relax and the vibration of the middle ear returns to normal. As the elicitor's presentation level increases, the effect of the acoustic reflex increases
context_page_description: The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube, and connects to the malleus bone. Its role is to dampen loud sounds, such as those produced from chewing, shouting, or thunder. Because its reaction time is not fast enough, the muscle cannot protect against hearing damage caused by sudden loud sounds, like explosions or gunshots.
context_section_description: The tympanic reflex helps prevent damage to the inner ear by muffling the transmission of vibrations from the tympanic membrane to the oval window.  The reflex has a response time of 40 milliseconds, not fast enough to protect the ear from sudden loud noises such as an explosion or gunshot. 
    Thus, the reflex most likely developed to protect early humans from loud thunder claps which do not happen in a split second.
  The reflex works by contracting the muscles of the middle ear, the tensor tympani and the stapedius.  This pulls the manubrium of the malleus inwards and tightens it. This tightening prevents the vibrations from disturbing the perilymph. Withdrawal from drugs such as benzodiazepines had been known to cause tonic tensor tympani syndrome (TTTS) during withdrawal. The tympanic reflex will also activate when loud vibrations are generated by the person themselves. The tensor tympani can often be observed vibrating while shouting at an increased volume, dampening the sound somewhat.
caption: Examples of the onset and recovery of the acoustic reflex measured with a laser Doppler velocimetry system
exif: {}