title: Form and function of lacunae in the ovary of the laying hen.
abstract: BACKGROUND
  Spontaneous atresia of large, yolky, ovarian follicles occurs in the chicken and in other species when the stimulus for ovulation ceases. This means that as much as 40 ml of yolk must be resorbed by the ovary if normal ovarian morphology is to be regained. This study examines the process of yolk resorption in the ovarian stroma following bursting atresia.
  
  
  METHODS
  Light, transmission, and scanning electron microscopy were used to study the morphology of lacuna spaces and their changes in ovaries of broiler and layer breeds of domestic chicken, both in actively laying birds and in birds undergoing spontaneous or induced follicular atresia. A comparative study was made of the ultrastructural differences between lacuna-lining cells, blood-vessel endothelium, and germinal epithelium of the ovary.
  
  
  RESULTS
  Transformation of lacuna-lining cells and peritoneal cells into macrophages occurred after bursting atresia and exposure of these cells to released yolk. Complete atresia of large yolky follicles occurred very quickly.
  
  
  CONCLUSIONS
  The resorption of this large volume of yolk, at least in part, seems to be mediated by the transformed lacuna-lining cells.
authors.affiliation: Department of Veterinary Pathology, University of Queensland, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Nili
authors.forename: W R
authors.initials: WR
authors.lastname: Kelly
mesh_terms: D000818:Animals; D002645:Chickens; D004530:Egg Yolk / Q000000981:diagnostic imaging / Q000502:physiology* / Q000648:ultrastructure; D005260:Female; D005496:Follicular Atresia / Q000502:physiology*; D008854:Microscopy, Electron; D010053:Ovary / Q000000981:diagnostic imaging / Q000502:physiology* / Q000648:ultrastructure; D011187:Posture; D014463:Ultrasonography