Hearing

• Central Nervous System (CNS)

  Can be divided into motor output (somatic and autonomic) and sensory system (Somatic and special senses).
• What are the main parts of the ear

  Outer, middle and inner
• What are the names of the smallest bones in the body

  Malleus, Incus, Stapes.
• What is the malleus called

  The hammer
• Whhat is the incus called

  The anvil
• What is the stapes called

  The stirrup
• What is the pinna made of

  Elastic cartilage
• What is hte tympanic membrane

  The eardrum
• What nerve connects the cochlea to the brain

  Auditory nerve
• Describe the movement of sound through the ear

  Travels down the auditory canal to the tympanic membrane. It then travels through the malleus, incus and stapes. Then it travels to the oval window and into the cochlea.
• Where is the organ of corti located

  In the cochlea
• What does the external auditory canal do

  Collects and focuses sound waves
• How is sound passed through the middle and inner ear

  As vibrations
• What is the role of the ligaments in the middle ear

  They change the efficiency of sound travel.

  Sound travel is most efficient in quiet environments.
• What is the innermost part of the cochlea called

  The helicotrema
• Label the diagram of the ear

  X.

  A) Outer ear

  B) Middle ear

  C) Inner ear

  D) Auditory canal

  E) Pinna

  F) Malleus

  G) Incus

  H) Stapes

  I) Semicircular canals

  J) Cochlea

  K) Auditory nerve

  L) Tympanic membrane

  
• Describe the vestibular canal

  Connects to the oval window and is made of perilymph.
• What are the 3 canals in the cochlea

  Vestibular, Tympanic and cochlear
• Describe the tympanic canal

  Made of perilymph
• Label the cochlea

  X.

  A) Cochlear duct

  B) Auditory nerve

  C) Organ of Corti

  D) Vestibular canal

  E) Tympanic canal

  F) Basement membrane

  
• What is the difference between endolymph and perlymph

  Endolymph has more potassium ions
• What type of fluid fills the cochlear duct

  endolymph
• Where does the organ of corti sit

  On the basilar membrane
• Describe the features of the basilar membrane

  The part closer to the oval window has short, stiff fibres and detects high frequencies.

  The part closer to the apex has long, flexible fibres that detect low frequencies.
• Describe the movement of sound through the cochlea

  The stapes vibrate and pass onto the oval window.

  The oval window pushes in as the round window pushes out.

  The vibrations travel through the perilymph of the vestibular canal up to the helicotrema.

  They then travel through the perilymph of the tympanic canal.
• What is the basilar membrane made of

  Collagen fibres of different lengths.
• Describe how vibrations are transmitted to an electrical signal

  As sound travels along the tympanic canal, the basilar membrane vibrates.

  Stereo cilia detect movement, which causes depolarisation of the hair cells.

  A neurotransmitter is released, which activates sensory neurons.

  The signal is sent via the auditory nerve to the brain.
• How many rows of hair cells are in the organ of corti

  3 outer rows and 1 inner row.
• Describe the structure of the hair cells

  Stereo cili are on the apical surface. They are made of actin filaments.
• What is the vestibulocochlear nerve

  The auditory nerve
• What is the vestibular apparatus made of

  The semicircular ducts, utricle and saccule.
• Label this and state what it is

  It is the vestibular apparatus.

  A) Utricle

  B) Semicircular canals

  C) Saccule

  D) Cochlea

  
• What part of the ear is envolved in balance

  The vestibular apparatus
• What are the semicircular canals filled with

  endolymph
• Where are the macula found

  in the utricle and saccule
• What is this and label it

  It is the macula.

  A) Otoliths

  B) Hair cells

  C) Stereo cilia

  D) Auditory nerve

  
• What do the otoliths contain

  Calcium carbonate
• How is head position detected.

  When the head is tilted forward, the gravity pulls the otoliths forward. This causes the stereo cilia to bend. A signal is sent to the brain via the auditory nerve.
• What detects rotational accelertion and ddeceleration

  The semicircular canals
• What detects head position

  The utricle and saccule.