L3 - Hearing and equilibrium

• What are the special senses discussed in the material?

  Hearing and equilibrium
• What is mechanoreception?

  Sense of force or displacement from mechanical stimuli
• Why is mechanoreception considered an ancient sense?

  It is found in all organisms and cells
• What are some important functions of mechanoreception?

  Hearing, balance, proprioception, touch, blood pressure
• What is a hair cell?

  Epithelial sensory receptor cell
• What are stereocilia?

  Microvilli ordered in increasing height
• What is the role of kinocilium in hair cells?

  It mediates directional arrangement of stereocilia
• What happens to kinocilium in the adult cochlea?

  It is not present in the adult cochlea
• How do hair cells communicate with sensory neurons?

  Through the release of neurotransmitters
• What are tip-links in hair cells?

  Connect the tops of stereocilia and open channels
• How do tip-links function in mechanoreception?

  They pull channels open when stereocilia move
• What occurs when stereocilia move toward the tallest one?

  Channels open, causing depolarization
• What is the result of movement away from the tallest stereocilia?

  Channels close, leading to hyperpolarization
• What is the graded neurotransmitter release from hair cells?

  It alters action potential frequency in neurons
• What roles do hair cells play?

  Involved in hearing and balance
• How do hair cells respond to different stimuli?

  Location and accessory structures determine activation
• What are the three distinct regions of the ear?

  External, middle, and inner ear
• What is the function of the external ear?

  Collects sound waves and channels them inward
• What does the tympanic membrane do?

  Transfers sound energy to auditory ossicles
• What is the role of the middle ear?

  Amplifies sound vibrations and conveys them
• What is the function of the auditory ossicles?

  Transfer and amplify sound waves/vibrations
• What is the attenuation reflex?

  Muscles contract to reduce ossicle movement
• What does the auditory tube do?

  Links middle ear with nasopharynx for pressure equalization
• What are the two main divisions of the inner ear?

  Bony labyrinth and membranous labyrinth
• What is contained in the bony labyrinth?

  Semicircular canals, vestibule, and cochlea
• What is the function of the cochlear duct?

  Contains hair cells for sound detection
• What is the role of inner hair cells?

  Sound detection and neurotransmitter release
• How do outer hair cells function?

  Change shape to amplify sound detection
• What defines sound?

  Produced by a vibrating object and propagated by molecules
• How is frequency measured?

  In hertz (Hz, cycles per second)
• What does amplitude measure?

  Loudness or sound intensity
• What happens when sound enters the auditory canal?

  Tympanic membrane vibrates and transmits sound
• What causes pressure waves in the inner ear?

  Vibration of the oval window
• How does sound transduction occur?

  Displacement of basilar membrane activates hair cells
• What defines loudness detection?

  Amplitude of vibrations on the basilar membrane
• How does frequency detection occur?

  Based on the structure of the basilar membrane
• What is place coding in frequency detection?

  Neurons synapse with specific areas in auditory cortex
• What sound causes the greatest displacement of the basilar membrane?

  Sounds with high amplitude and frequency
• Where is the proximal end of the basilar membrane located?

  Next to the oval window
• Where is the distal end of the basilar membrane located?

  Next to the round window