Oogenesis

Oogenesis produces female gametes (__)

Ova

Ovarian Development and Oogenesis:
- Egg cells undergo a _____ in number during fetal development, peaking at around seven million before many are resorbed.

-significant increase

-Located in the ovaries, consisting of an egg cell surrounded by a single layer of follicular cells.
- Follicular cells increase in number, causing changes in the ovary.

Primordial Follicles

Before birth female stem cells (oogonia) complete mitotic division where stem cells undergo mitosis producing __________

primary oocytes

Puberty to menopause ______ are stimulated to continue development. It will take several monthly cycles before some of them go on to develop toward ______ and of these only one (usually) dominates and is ovulated

-primordial oocytes

-tertiary follicle

Oogenesis Meiosis:
- Unlike in males, oogenesis results in ____ viable egg cell.
- The other DNA is discarded as non-viable ____

- One ___ cell produces one complete ___ cell and three polar bodies

-only one

-polar bodies.

-2n → 1n

• first follicles formed in fetus contain one primary oocyte

• Surrounded by single layer of squamous follicularcells

Primordial follicle

several primordial follicles hormonally stimulated [LH and FSH] to develop into primary follicles

Follicular (preovulatory) phase

Oocyte develops inside ____ located in cortex Clustered together in regions called egg nests

ovarian follicle

Follicular cells become cuboidal, and a glycoprotein layer called the
zona pellucida forms around the egg cell.

Primary follicle

Primary Follicle (2)

• Secrete estrogen as it mature

• Stimulates changes in uterine lining

Regulates sperm-egg interactions (has proteins to which sperm will bind)

Zona pellucida

Characterized by fluid-filled spaces called antrum.

Secondary Follicle

____forms from primary follicle – pockets form in thick granulosa cell layer fill with fluid

Secondary follicle

_____ layer of cells formed outside granulosa: Produce androgens

Thecal cells:

_____ fluid filled pockets have merged not single antrum

Antral follicle

Antral Follicle: _______ and its capsule of granulosa cells

 project into ______ on stalk. Follicle continues to enlarge; creates bulge on ovary surface

-Primary oocyte

-antrum

-Primary oocyte, suspended in _______ , completes ______ forms secondary oocyte and first polar body

-Secondary oocyte arrests development in _____ completes second division if fertilized

- prophase I

-meiosis I

-metaphase II