Dense granules (lysosomes?) and crystals in the thyroids of senile rats.
D000375:Aging; D000818:Animals; D004847:Epithelial Cells; D008247:Lysosomes; D008297:Male; D008854:Microscopy, Electron; D051381:Rats; D013961:Thyroid Gland / Q000166:cytology* / Q000502:physiology