ex. 26 [olfaction and taste]

Cards (18)

  • receptors for taste and smell are classifies as chemoreceptors because they respond to chemicals in solution
  • pseudostratified ciliated columnar epithelium a.k.a. olfactory epithelium is the organ of smell, occupying the roof lining of nasal cavity
  • three cell types in olfactory epithelium
    • olfactory sensory neurons: specialized receptor cells; bipolar w/ nonmotile cilia
    • supporting cells: columnar cell surrounding and supporting olfactory sensory neurons; bulk of epithelium
    • stem cells: located near basal surface of epithelium, form new sensory neurons
  • filaments of olfactory nerve penetrate cribriform foramina and synapse in olfactory bulbs
  • taste buds contain specific receptors for sense of taste
  • most taste buds are located in papillae on the dorsal surface of tongue and some are found on soft palate, epiglottis, pharynx, and inner surface of cheek
  • taste buds located in side walls of large vallate papillae (v-shape in posterior tongue surface), side wall of foliate papillae and fungiform scattered everywhere
  • each taste bud consists of
    • gustatory epithelial cells: taste receptors; have long microvilli called gustatory hairs that project through taste pore
    • basal epithelial cells: precursor cells that divide to replace gustatory epithelial cells
  • when gustatory hairs contact food molecules dissolved in saliva, gustatory epithelial cells depolarize. afferent neurons innervating taste buds are
    • facial nerve (7): anterior 2/3
    • glossopharyngeal (9): posterior 1/3
    • vagus (10): few fibers from pharyngeal region
  • sweet receptors: sugars, saccharine, some lead salts, some amino acids
  • sour: hydrogen ions
  • salty: influx of Na ions
  • umami: a savory taste that is produced by the amino acid glutamate
  • bitter: alkaloids
  • nasal
    A) glomeruli
    B) olfactory stem cell
    C) olfactory sensory neuron
    D) supporting cell
    E) olfactory epithelium
    F) supporting cell
    G) olfactory sensory neuron
    H) olfactory cilia
  • supporting cells: surround and support olfactory sensory neurons, forming a bulk of the olfactory epithelium
  • olfactory adaption: how smells are less noticeable after some time spent smelling it
  • tongue
    A) foliate papillae
    B) fungiform papillae
    C) vallate papilla
    D) gustatory hair
    E) taste pore
    F) gustatory epithelial cell
    G) basal epithelial cell