Oogenesis

Oogenesis

• is the process by which the female gametes (ovum) are created

• it create haploid cells

• 1 egg produce every month

• Initiated EMBRYONIC STAGE

• start in FETUS

Ovary

• site of oogenesis

6-7 weeks

• starts of oogenesis

20 weeks

6/7 million oogonia produce in this week

2 million oogonia

• at birth it produces this number of oogonia

oogonia

• germinal epithelium in ovary divided by mitosis producing a couple of milliom oogonia

• multiply by mitotic divisions forming egg nest

• No more ______ are formed or added after birth

Primary oocytes

• one egg from the egg nest grow and become the ________

Meiotic arrest I

• oogonium develips into primary oocytes (oocytogenesis)

• These primary oocyte remains arrested at this stage

60000 - 80000

• the number of primamry oocytes remains at puberty

400, menstrual cycle

• out of these only about _____ primary oocytes will enter in the _________. and out of these only one will form a ovum during each ________

38-48 hr

Meiosis I completed about ______ prior to ovulation

Meiotic arrest II

• after puberty

• meiosis continue

• one polar body, and one secondary oocytes formed

• it will still remain arrested till fertilization with sperm

Secondary oocytes , metaphase II

• again enters in meiotic arrest I (at the _______)

Tertiary follicle

• Graffian follicle contains secondary oocytes

• large antrum filled with fluids

• it rupture due to LH (luiteinizing hormones) surge and secondary oocytes relased

Primordial Follicle

• This is the initial stage where a single oocytes is surrounded by a single layer of flattened granulosa cell

primary follicle

• the flattened granulosa cells begin to proliferate and become cuboidal with continued development of the oocyte and the formation of the zona pellucida, a glycoprotein coat around the oocytes

Secondary follicle

• multiple layers of granulosa cells

• the theca layer forms around the follicle

Tertiary follicle

• Graafian follcle

• a fluid filled space caleed antrum development within the granulosa cells, and the theca differentiates into theca interna and externa layers

Pre-ovulatory follicle

• graafian follicle

• this is the mature, dominant tertiary follicle that is ready for ovulation, triggered by a surge in luteinizing hormones

Ovulation

• Graafian follicle ruptures to release the secondary oocytes the egg into the fallopian tubes

Carpus luteum

• after ovulation, the remaining follicle cells differentiate and form, which produces hormones primarily prosterone, to support a potential pregnancy

oogonium

• the primordial germ cells that colonize the ovary in the female fetus, undergoing mitosis and rapid proliferation before differentiating into primary oocytes around 20 weeks' gestation.

diploid/46 (2n)

• number of chromosome or ploidy in oogonium

2C

• Chromatids number in oogonium

Oocytogenesis

• process of oogonia

• mitosis cell cyle process

• the process where oogonia (immature germ cells) transform into primary oocytes

Primary oocytes

• cells in the ovaries that have begun the first stage of meiosis (meiosis I) but are arrested in the prophase I stage

• 46 (2n) chromosomes - diploid

Ootidogenesis

• process of primary oocytes

• the step in which the primary oocyte turns into an ootid

• Meiosis I

Folliculogenesis

• is the development and growth of the ovarian follicle, a structure containing the egg cell

Dictyate

• in prophase for up to 50 years

• a prolonged resting phase in the development of female mammalian oocytes (eggs) during prophase I of meiosis

secondary oocyte

• the larger of two cells produced after a primary oocyte completes the first meiotic division (meiosis I) during oogenesis

• haploid 23 (1n) chromosomes

• 2c chormatids

• ootidogenesis in meiosis ii

• halted in metaphase II until fertilization

ootid

• a female germ cell that refers specifically to the egg or ovum

• haploid/23(1n) chromosomes

• 1c chromatids

• Ootidogenesis in meosis ii

• completed in minutes after fertilization

Polar body

• a small haploid cell that is formed at the same time as an egg cell during oogenesis, but generally does not have the ability to be fertilized