11

OvariesOvaries

Blood supply Blood supply ovarian folliclesovarian follicles

Cells around the oocyte Cells around the oocyte are called:are called:

Follicle cells Follicle cells Granulosa cells Granulosa cells

22

FolliclesFollicles Primordial folliclePrimordial follicle Primary folliclePrimary follicle Secondary follicleSecondary follicle Graafian follicleGraafian follicle OvulationOvulation Corpus luteumCorpus luteum

Oogenesis: PubertyOogenesis: Puberty--At puberty, one activated primary At puberty, one activated primary oocyte produces two haploid cells oocyte produces two haploid cells

-Ovulation-Ovulation

-If penetrated by sperm the second -If penetrated by sperm the second oocyte completes meiosis IIoocyte completes meiosis II

33

Ovarian CycleOvarian Cycle

ovaries grow and secrete small amounts of ovaries grow and secrete small amounts of estrogens that inhibit the hypothalamic release of estrogens that inhibit the hypothalamic release of GnRHGnRH

As puberty nears, GnRH is releasedAs puberty nears, GnRH is released

Monthly Monthly Follicular phase Follicular phase OvulationOvulation Luteal phaseLuteal phase

44

Fertilization and Embryonic Fertilization and Embryonic DevelopmentDevelopment

Fertilization = The fusion of two haploid gametes (egg and Fertilization = The fusion of two haploid gametes (egg and sperm)sperm)

n – haploid, 23 chromosomesn – haploid, 23 chromosomes2n – diploid, 46 chromosomes2n – diploid, 46 chromosomes

55

The three stages of FertilizationThe three stages of Fertilization

1.1. PenetrationPenetration

2.2. Activation Activation

3.3. FusionFusion

66

Early DevelopmentEarly Development

77

Cleavage

Implantation

Gastrulation

GastrulationGastrulation

EctodermEctoderm

EndodermEndoderm

MesodermMesoderm

88

Extra Embryonic Membranes:Extra Embryonic Membranes:

1.1. Yolk SacYolk Sac2.2. AmnionAmnion3.3. AllantoisAllantois4.4. ChorionChorion

99