digestive system part 3

  1. Teeth
    are accessory digestive organs located in sockets of the alveolar processes of the mandible and maxillae.  The alveolar processes are covered by gingivae or gums which extend slightly into each socket
  2. periodontal ligament or membrane
    lines the sockets and consists of dense fibrous connective tissue that anchors the teeth to the socket walls
  3. crown
    is the visible portion above the level of the gums
  4. roots
    embedded in the socket
  5. neck
    is the constricted junction of the crown and root near the gum line.
  6. dentin
    forms the majority of the tooth.  It consists of a calcified connective tissue that gives the tooth its basic shape and rigidity.  It is harder than bone because of its calcium content.
  7. enamel
    this covers the dentin of the crown and consists primarily of calcium phosphate and calcium carbonate. Harder than bone it is the hardest substance in the body.  It protects the tooth from wear and tear and acids that can easily dissolve dentin
  8. cementum
    the dentin of the root is covered by this a bone like substance, which attaches the root to the periodontal ligament.
  9. pulp cavity
    the dentin of a tooth encloses a space.  The enlarged part of the space called this lies within the crown and is filled with pulp, a connective tissue containing blood vessels, nerves and lymphatic vessels.
  10. root canals
    narrow extensions of the pulp cavity.  They run through the root of the tooth.
  11. dentitions
    humans have two of these, or sets of teeth: deciduous and permanent
  12. deciduous teeth
    begin to erupt at about 6 months of age and approx 2 teeth per month thereafter until all 20 are present
  13. Deciduous teeth: central or lateral incisors
    are closest to the midline, are chisel-shaped and adapted for cutting into food.
  14. Deciduous teeth: cuspids or canines
    next to the incisors moving posteriorly thay have a pointed surface and are used to tear and shred food
  15. Deciduous teeth: first and second molars
    posterior to the cuspids, which have four cusps. They crush and grind food to prepare it for swallowing.
  16. permanent teeth
    replace the deciduous teeth by age 12. They contain 32 teeth and resemble deciduous teeth with a few exceptions
  17. Permanent teeth: first and second premolars
    replace the deciduous molars. They have two cusps and one root and are used for crushing and grinding
  18. molars
    erupt into the mouth posteriorly to the premolars.  They do not replace any deciduous teeth and erupt as the jaw grows. first ones at age 6 second at age 12 and the last at 17
  19. mastication
    chewing.  seen in mechanical digestion.  food is manipulated by the tongue, ground by the teeth and mixed with saliva.
  20. bolus
    a soft, flexible easily swallowed mass
  21. salivary amylase
    initiates the breakdown of starch.  Seen in chemical digestion. It breaks down carbs into monosaccharides.
  22. lingual lipase
    contained in saliva, this enzyme becomes activated in the acidic environment of the stomach and thus starts to work after food is swallowed.  It breaks down dietary triglycerides into fatty acids
  23. upper esophageal sphincter
    the muscularis becomes slightly more prominent at each end of the esophagus. This one consists of skeletal muscle and regulates the movement of food from the pharynx into the esophagus
  24. lower esophageal sphincter
    which consists of smooth muscle tissue.  It regulates the movement of food from the esophagus into the stomach.
  25. adventitia
    the superficial layer of the esophagus, rather than the serosa in the stomach and intestines, It attaches the esophagus to surrounding structures
  26. esophagus
    it secretes mucous and transports food into the stomach.  It does not produce enzymes and it does not carry on absorbtion
Card Set
digestive system part 3
digestive system part 3