Scanning electron microscopy of volk absorption in early chick embryos.
Fresh pullet eggs (White Leghorn Strain) were incubated from 6-19 hours. Blastoderms were fixed in situ with aldehyde fixative, post-osmicated in 2% OsO4, dehydrated in acetone, critical-point-dried, mounted ventral side up, coated with palladium-gold wire and observed in a Cambridge Stereoscan S4 scanning electron microscope. Large extracellular yolk granules had a smooth surface and appeared to break up into smaller particles. Similar particles have been observed intracellularly in transmission electron microscopy. Numerous microappendages, mostly ruffles, suggest phagocytosis as a method of absorption of yolk granules into the cells. Absorption of yolk by the cells of the blastoderm involves an initial break up of yolk granules followed by phagocytosis.
D000818:Animals; D001756:Blastoderm / Q000648:ultrastructure; D002642:Chick Embryo; D004530:Egg Yolk; D005260:Female; D006046:Gold; D008855:Microscopy, Electron, Scanning; D010165:Palladium; D010587:Phagocytosis
D010165:Palladium; D006046:Gold