Biomedical core

  1. The five primary tastes
    sweet; sucrose

    salty; taste of NaCl (table salt) in water

    bitter; quinine

    Acid; measures concentration of H+ ions

    Umami; Japanese for "tasty" or "meaty:, as in protein rich foods such as sushi.
  2. Taste receptors found on
    lips, tongue, palate
  3. Receptors for things we "want"
    tend to be closer to the front of the tongue
  4. Receptors for things we don't want tend to be
    closer to the back of the tongue
  5. Filiform papillae, which look
    little threads, cover most of the tongue surface. These are non taste buds
  6. Several gustatory receptor cells and supporting cells are
    clustered in each taste bud.

    *Individual taste buds cover entire surface of tongue
  7. Three groups of taste buds on tongue
    Fungiform papillae; little mushrooms

    Foliate papillae; leaf-shaped, found along lateral surface of the posterior tongue.

    Vallate papillae; form a V shaped row along the posterior tongue. Usually 7-10 of these
  8. Gustatory Pathways to Brain:
    3 cranial nerves carry taste sensations

    facial (CN VII): anterior 2/3 of tongue

    glossopharyngeal (CNIX): posterior 1/3

    vagus (CN X): tonsils, palate, oropharynx



    Primary gustatory cortex is in  "mouth area" of postcentral gyrus
  9. These three nerve branches combine to form a bundle of axons called the
    chorda tympani
  10. The chorda tympani carries information to the
  11. The sense of hearing depends on
    the ear receiving pressure waves of air
  12. Pressure waves of air are the relevant
    stimulus for the auditory system
  13. Pressure waves of air arrive at the ______, the external part of the ear, and are carried through the ______ ______ _____ to press against the _______ ________. The tympanic membrane vibrates as pressure waves of air push against it.
    auricle; external auditory canal; tympanic membrane
  14. Auditory Ossicles:

    Bone of the Ear


  15. Inner ear structures:
    Semicircular canals (balance)

    Cochlea (hearing)
  16. Cochlea
    *has 2 1/2 turns

    • *Two fluid-filled chambers
    • -Scala tympani
    • -Scala vestibuli

    *Between these chambers: spiral organ
  17. Spiral organ is where auditory __________ occurs
  18. Spiral Organ:

    Auditory Transduction
    *Auditory receptors (hair cells) sit on basilar membrane

    *Rows of 3 outer hair cells and one inner hair cell

    *Hairs (modified cilia) embedded in tectorial membrane

    • *Hair cells synapse onto 1" afferents
    • -cell bodies in spiral ganglion
    • -axons form cochlear branch of CN VIII
  19. The hair cells are small and don't send their information far.  They make contact on a 1 degree afferent fiber with a cell body in the ______ ______ and axons that travel in the _______ branch of the __________ nerve.
    spiral ganglion; cochlear; vestibulocochlear (CN VIII)
  20. 2 accessory structures are associated with the ear:
    ceruminous glands

    auditory glands
  21. Ceruminous glands produce the
    waxy substance found within the ear. Cerumen helps trap dirt and insects,  and can even produce a protective earplug if the ear is exposed to loud noises.
  22. Auditory tube is a
    tube that connects the middle ear to the nasopharynx. This equalizes the pressure on both sides of the tympanic membrane unless the tube becomes swollen or clogged with mucus.
  23. The Sound Conduction Pathway:

    1. Waves of air arrive in external auditory canal.

    2. Air moves tympanic membrane

    3. Tympanic membrane moves ossicles

    4. Stapes moves oval window

    5. Oval window moves perilumph fluid in scala vestibuli
  24. The Sound Conduction Pathway:

    6. Waves of fluid in scala vestibuli set up vibrations in basilar membrane, which moves hair cells

    7. Fluid can pass from scala vestibuli to scala tympani at helicotrma

    8. Fluid in scala tympani

    9. Round window is outlet for pressure
Card Set
Biomedical core
Objective 28-33