DRUG DESCRIPTION. NAMENDA XR is an orally active NMDA receptor antagonist. The chemical name for memantine hydrochloride is 1-amino-3,5-dimethyladamantane hydrochloride with the following structural formula: The molecular formula is C12H21Nâ¢HCl and the molecular weight is 215.76.
There are three main parts to the ear, including the inner ear, middle ear and outer ear. In order for hearing to occur, there is a sequence of actions that must occur to transform waves of sound in the air into electrical impulses. These impulses are transmitted to the brain by the auditory (hearing) nerve.
7.1 Structure of the Ear and Pitch Perception. Parts of the ear: Ear lobe - concentrates high frequencies, gives sense of direction. Animals control ear lobes. Ear canal - open-closed resonator, enhances frequencies around its fundamental resonance, which is in the range of 2000 â 5000 Hz. Resonant frequency used to determine length of canal for fitting hearing aids. Ear drum - converts sounds waves to mechanical vibrations, much like a microphone. Inner ear bones - transfers mechanical energy to oval window on cochlea. Protects against loud noises. Cochlea - fluid filled canal with Basilar membrane running along its length.