reproduction > ovary > normal histology > oocyte maturation

see also: Location - Structure - Development - Granulosa cells
Various systems have been proposed to stage oocyte growth. Such classifications take into account morphological features of the growing oocyte and its nucleus, oocyte size, and granulosa cell layer properties. The staging presented here is mainly descriptive, and is based on Lambert 1970 1 and Selman 1993 2. Classical staging terminology is given for comparison.
For practical purposes, i.e. evaluation of effects of toxicants, a simplified classification, e.g. distinguishing between previtellogenic and vitellogenic oocytes, may be sufficient. Alternatively, histomorphometrical quantification of oocyte sizes (surface area, diameter) may be helpful to analyse toxicological effects.

All images below are taken from adult female zebrafish ovaries; H&E or PAS staining. Some sets show clusters of cells with a single cell highlighted.



oogonium



proliferating oogonia



primary oocytes - stage 1; first meiotic division - leptotene stage



primary oocytes - stage 1; first meiotic division - zygotene stage



primary oocytes - stage 1; first meiotic division - zygotene stage



primary oocytes - stage 1; first meiotic division - pachytene stage



primary oocytes - stage 1; first meiotic division - pachytene stage



primary oocytes - stage 1; first meiotic division - diplotene stage



primary oocytes - stage 2 (previtellogenic)



primary oocytes - stage 2 (previtellogenic)



primary oocytes - stage 3 (previtellogenic)



primary oocytes - stage 4



primary oocytes - stage 4



primary oocytes - stage 5



primary oocytes - stage 5



primary oocytes - stage 6



primary oocytes - stage 6-7



primary oocytes - stage 6-7



secundary oocytes - stage 7



secundary oocytes - stage 7



follicle derivatives - corpus atreticum (preovulatory)



follicle derivatives - corpus atreticum (postovulatory)




References
  1. Lambert-JG. The ovary of the guppy Poecilia reticulata. The granulosa cells as sites of steroid biosynthesis. Gen. Comp Endocrinol. 15:464-476; 1970.
  2. Selman-K, Wallace-RA, Sarka A, Qi-X. Stages of oocyte development in the zebrafish, Brachydanio rerio. J. Morphol. 218:203-224; 1993.
  3. Yamamoto-TS. Morphological and cytochemical studies on the oogenesis of the fresh water fish, medaka (Oryzias latipes) (in Japanese, referred at The medaka fish homepage: stages in development of medaka). Japan J. Ichthyol. 4: 170-181; 1955.












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