Light micrograph of a mature human oocyte (egg),photographed at the metaphase I stage of its second meiotic division. This second meiotic division is not completed until after penetration of the ovum by a single spermatozoon - that is,until fertilisation occurs. In this image,a single spermatozoon is visible at the 10 o'clock position,in the process of penetrating the corona radiata,a layer several cells thick which surrounds the oocyte. A further barrier to sperm,the Zona pellucida,directly envelops the oocyte beneath the corona radiata | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / ANDY WALKER, MIDLAND FERTILITY SERVICES |
Taille de l’image : | 5117 px × 3616 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |