Asudden, loud noise will reflexively cause the tensor tympani muscle to and cause the stapedius muscle to

A sudden, loud noise will reflexively cause the tensor tympani muscle to contract, pulling on the malleus ossicle (tiny bone), and cause the stapedius muscle to contract, pulling up on the stapes ossicle.
When presented with a high-intensity sound stimulus, these two muscles contract, known as the acoustic (auditory) or stapedius reflex. The reflex decreases the transmission of vibrational energy to the cochlea, where it is converted into electrical impulses to be transmitted to the brain via the auditory nerve to then be processed.