Unit 2: Nervous System

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Unit 2 Nervous System

• Hearing Notes

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(1) Ear Design

• Ear is like a well designed funnel.
• Sound waves spiral down into auditory canal.
• Sound Waves smack against ear drum (tympanic
  membrane).

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(2) Vibrations

• Sound Waves ? Tympanic Membrane
• Eardrum literally like the leather on a drum
• T-Membrane ? Hammer ? Anvil ? Stirrup
• Hammer, Anvil and Stirrup are very small bones in
  inner ear
• Stirrup ? Oval Window ? Inner Ear Fluid

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(3) Cochlea

• Cochlea Snail like structure in inner Ear.
• Contains Organ of Corti
• Contains hearing receptors / hair cells
• Hair cells stimulated by movement of Inner Ear
  Fluid
• Basilar Membrane
• Type of membrane on specific receptors
• Responds to changes in pitch
• Fluid ? Receptors ? Cochlear Nerve ? Brain

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(4) Equilibrium Balance

• Your ears keep track of your bodys position.
• Equilibrium receptors lie within the inner ear of
  your ears (Vestibular Apparati).
• 2 Types of Equilibrium
• Static
• Dynamic

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(5) Static Equilibrium

• Head Balance
• Static Receptors Maculae
• On top of maculae lies the otolithic membrane
  (gel-like)
• Head Moves ? Otoliths Moves!
• Movement of Otolithic ? Receptor ? Impulse to
  Vestibular Nerve Brain
• Tells your brain when your head is not upright.

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(6) Dynamic Equilibrium

• Rotation Angles of Head
• Semicircular Canals of Cochlea
• Contain receptors Crista Ampullari
• Crista Ampullari contain receptor hairs,
  endolymph fluid and a capula cap
• Body Movement ? endolymph movement ? Push on
  Capula Cap ? Receptor Hairs ? Vestibular Nerve
  Brain

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• http//www.youtube.com/watch?vvTiGskc1o48

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(7) Motion Sickness

• Inefficient dynamic equilibrium
• Semicircular Canals either too sensitive or too
  slow at sending messages
• Too many visual messages
• Too many inner ear messages
• Visual conflicts with Inner Ear
• Unique to each individual

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(8) Deafness

• Deaf Any hearing loss
• Types
• Conduction
• Sensorineural

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(9) Conduction Deafness

• Something Blocks Tympanic Membrane
• Sound Waves cannot reach Ear Drum Inner Ear
• Causes
• Ear Wax
• Ruptured Ear Drum
• Injured Hammer, Anvil and/or Stirrup
• Usually Temporary, Solved by Surgery

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(10) Sensorineural Deafness

• Damage to actual parts of ears
• Receptor Cells
• Cochlea
• Vestibular Nerve
• Can be hereditary, damage from disease/virus,
  damage from loud noises
• Often permanent