Female Reproductive System
Functions:
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•
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Oocyte Production
Receive Sperm
Develop Offspring
Deliver Offspring
Oocyte Production
Ovaries:
Visceral Peritoneum
Germinal Epithelium
Cortex
- (dense C.T.)
- Contain follicles,
Each with a single ovum
Medulla
-(loose C.T.)
- contains blood vessels,
Lymph vessels and nerves
- Continuous with ovarian ligament
Egg Production –
Oogenesis
Begins before birth
2 million in ovaries
At puberty, meiosis restarts
Oogonia –
divide by mitosis
during fetal period
Secondary
oocyte
(continues
meiosis but
stalls after
metaphase II until
fertilization)
Fertilized
ovum
Second
Polar
Body
Primary
Oocytes
(stall after
prophase I
of meiosis
until puberty)
First
Polar
Body
(disfunctional)
Second
Polar
Body
Second
Polar
Body
If fertilization
doesn’t occur,
these never form
and secondary
oocyte deteriorates
Egg Production –
Follicle Development
Primordial Follicles (1):
-Single layer
- flattened cells
At puberty:
cells enlarge = Primary Follicle
mitosis creates multiple layers (2,3,4)
Secondary
Follicle (5)
- Antrum forms
- cavity between oocyte and granulosa cells
- filled with fluid
- Continues to enlargen
- Estrogen secretion begins
- Glycoproteins are secreted
- form membrane = Zona Pellucida
- Expands until oocyte is isolated on a stalk and surrounding
capsule of granulosa cells = Corona Radiata
- Graafian Follicle bulges from ovarian wall (6)
Eruption = Ovulation
(7)
- Ruptured follicle collapses (8&9)
Luteal Phase
Antrum fills with clotted blood =
corpus hemorrhagicum
Corpus Luteum (8)
- forms from remaining granulosa
cells
- degenerates if no pregnancy
occurs
scar = corpus albicans (9)
- if pregnancy does occur, corpus
luteum remains as an endocrine
gland for about 3 months
Hormonal Regulation
Follows an approximately 28 day cycle
Day 1
Hypothalamus
- GnRH (gonadotropin releasing hormone)
- targets anterior pituitary gland
Anterior Pituitary Gland
- Gonadotropins:
LH (luteinizing hormone)
- targets thecal cells
outside follicle
Thecal cells secrete androgens
FSH (follicle stimulating hormone)
- targets follicle cells
Follicle cells convert androgens to estrogens
Estrogens - target endometrial cells
Hormonal Regulation
Estrogens
Negative feedback on hypothalamus
Positive feedback on follicle cells
Day 14
Estrogens reach critical threshold
Positive feedback on hypothalamus
LH and FSH spike
– triggers ovulation
- damages follicle
Corpus luteum forms
Estrogen levels decline
Progesterone and estrogen are produced
- Supports endometrium
Negative feedback on hypothalamus
- inhibits new follicle
development
LH declines as corpus luteum degenerates
estrogen and progesterone drop
sharply
Day 28
Cycle restarts!
FSH
Estrogen
LH
Progesterone
Hormonal Regulation
In the event of fertilization:
Embryo secretes hCG (human chorionic gonadotropin)
- acts like LH
- maintains corpus luteum for continued
production of estrogen and progesterone