Question

structure that protects the female gamete during meiotic division

Answer 1

Zona pellucida

During the birth of females, they have some special types of stem cells called oogonium.These are diploid cells(2n).During pre- puberty, these oogonium will be converted into primordial follicle(2n), which are being undrgone mieosis; but frozen at prophase I stage.When the female reaches puberty, she has tons of primordial follicles.The specific types of localized androgens stimulate some of the primordial follicle to be converted into the primary follicle(2n); a primary oocyte with a single layer of cuboidal/columnar cells surrounding it.The FSH released from the pituitary gland stimulates the conversion of the primary follicle into the early secondary follicle(2n). The secondary follicle has multiple layers of the cuboidal/columnar cells surrounding the oocyte.The FSH also stimulate the oocyte to produce a glycoprotein layer called 'Zona pellucida'.Zona pellucida is secreted by the follicular cells.It is an acellular layer and gelly layer.

ZONA PELLUCIDA has following functions:

• supports communication between oocyte and follicle cells
• protects oocyte,egg and embryo during development
• control interaction between ovulated egg and free swimming sperm

Further it passes through the late secondary follicle stage and ultimately forms the graffian follicle.During each menstrual cycle, pituitary gonadotropin completes the meiosis I the day before ovulation.During ovulation the graffian follicle breaks and the secondary oocyte frozen at metaphase II. inside it comes out with zona pellucida and corona radiata follicle cells surrounding it by the action of LH(Luteinizing hormone).