title: [Ultrastructural analysis of secretion-transport through the parotid duct].
abstract: BACKGROUND
  Mechanisms of secretion transport through the parotid duct (stenon's duct) and their influence on diseases of the parotid gland have not been investigated sufficiently until today.
  
  
  METHODS
  According to this background we performed histologic and scanning electron microscopical investigations of 23 parotid ducts in order to investigate the arrangement of fibrillar structures of the duct as well as get deeper insights into the physiology of secretion transport mechanisms.
  
  
  RESULTS
  The subepithelial soft tissue of the parotid duct could be divided into two layers. The inner layer measured about 100-200 microm and consisted of collagen and elastic fibres running in a spiral arrangement. The outer layer varied in its thickness and was composed of collageous fibres, which were mostly arranged longitudinally.
  
  
  CONCLUSIONS
  The arrangement of collagen fibrils in the wall of the parotid duct seems to influence secretion transport. Due to the spiral organization of collagen fibrils, distension of the duct is likely to be associated with a "wring-out" mechanism leading to unidirectional transport of saliva into the oral cavity. A muscular sphincter at the outlet of the parotid duct did not exist. The duct pierced the buccinatory muscle. Here, it was surrounded by sceletal muscle fibres that lead to a functional closure during contraction. Our results indicate that an active transport of saliva through the parotid duct--as so far assumed--is unlikely.
authors.affiliation: Anatomisches Institut der Universität Schleswig-Holstein Campus Kiel, Kiel. hanneskutta@gmx.de
authors.forename: H
authors.initials: H
authors.lastname: Kutta
authors.forename: J
authors.initials: J
authors.lastname: May
authors.forename: M
authors.initials: M
authors.lastname: Jaehne
authors.forename: F P
authors.initials: FP
authors.lastname: Paulsen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000648:ultrastructure; D010306:Parotid Gland / Q000378:metabolism / Q000648:ultrastructure*; D012463:Saliva / Q000378:metabolism*; D018987:Salivary Ducts / Q000378:metabolism / Q000648:ultrastructure*; D015494:Salivary Gland Calculi / Q000175:diagnosis; D012472:Salivation / Q000502:physiology