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11.1.4. The ovule

The female gamete

The ovule is a large rounded cell, since it must have enough reserve substance, the yolk, so that the embryo can feed during the first days.

The ovule is an immobile cell in which it is distinguished:

  • The nucleus: spherical, with 23 chromosomes, half that of the rest of non-sexual cells. It has a large nucleolus.
  • The vitelo: reserve substances that allow the embryo is formed until develops placenta.

The ovule is surrounded by:    

  • The pellucid layer: gelatinous layer that surrounds and protects the egg.
  • The radiated crown: layer formed by follicular cells that accompanies the ovum and that collaborates in the formation of the placenta and female sex hormones.

Óvulo siendo fecundado por espermatozoide

By OpenStax College [CC BY 3.0], via Wikimedia Commons

Answer in your notebook

11.4.- What are gonads? What about gametes? Explain it with examples.