The Auditory System Flashcards
Recall the major structures of the ear involved in hearing
Middle ear
small air-filled space, contains three small bones called ossicles: the malleus, incus, and stapes. These are connected to the eardrum and the oval window
When sound waves enter the ear, they cause the eardrum to vibrate, which causes the ossicles to move.
The movement of the ossicles amplifies the sound waves and transmits them to the inner ear.
Inner ear
a complex, fluid-filled structure that contains the cochlea
The cochlea is a spiral-shaped tube that is divided into three fluid-filled chambers. The middle chamber, called the cochlear duct, contains the sensory hair cells that detect sound waves and transduce them into electrical signals that the brain can interpret
Explain the functional significance of the middle ear
amplifying and transmitting sound waves from the outer ear to the inner ear
helps to equalise pressure on both sides of the eardrum
middle ear is filled with air, while the inner ear is filled with fluid
Describe the fine structure of the cochlea
spiral-shaped structure in the inner ear
responsible for converting sound waves into electrical signals that the brain can interpret as sound.
three main parts: the scala vestibuli, the scala media, and the scala tympani.
also contains the organ of Corti, sits on the basilar membrane and contains the hair cells that detect sound waves.
The hair cells are arranged in rows along the length of the basilar membrane, and each row is sensitive to a different frequency of sound.
When the hair cells move in response to sound waves, they stimulate the release of neurotransmitters that generate electrical signals, which are then transmitted to the brain via the auditory nerve.
Recognise that the basilar membrane is displaced in a tonotopic manner
The basilar membrane is displaced in a tonotopic manner. Different regions of the basilar membrane vibrate preferentially in response to different frequencies of sound
Explain how hair cells act as mechanoelectrical transducers
Hair cells act as mechanoelectrical transducers by converting mechanical vibrations from sound waves into electrical signals. The hair bundle on each hair cell responds to the movement of the basilar membrane, which causes the stereocilia to bend and open ion channels, leading to the depolarization of the hair cell and the generation of a receptor potential. The receptor potential can then trigger the release of neurotransmitters, leading to the activation of sensory neurons and the generation of action potentials that are transmitted to the brain.
