Reproductive Physiology Flashcards
How are primary oocytes produced?
Produced by oogonia (stem cells) in the fetal ovaries
When/why does menopause start?
When there are no more functional primary oocytes
What phase are primary oocytes held in?
Meiosis I (unchanged from fetus)
What is released from the ovary at ovulation?
One secondary oocyte
When does completion of meiosis II begin?
When sperm contacts the egg (fertilization)
What are the two phases of the ovarian cycle?
- Follicular phase
2. Luteal phase
Follicular phase
Where the egg & granulosa cells develop up to the point of ovulation
Luteal phase
Where the leftover bits of the granulosa hang around & secrete hormones (mainly progesterone) to prepare the uterus lining (endometrium) for a zygote
Characteristics of a primary follicle
Has granulosa cells which grow & secrete fluid + produce an antrum
Characteristics of a mature follicle
Has a full antrum
Shoots out the peritoneal cavity
When does the luteal phase occur?
After the mature follicle leaves the peritoneal cavity
What is a primordial follicle?
Precursor to a primary follicle
Primordial cell: histology
Flat follicular cells
Primary follicle: histology
Cubodial granulosa cells
Zona pellucida = begins to form, stays until egg implants (protection; shell)
How does a primary follicle transition to a secondary follicle?
Granulosa cells proliferate & secrete follicular fluid which forms intracellular spaces
How does a secondary follicle transition into a mature follicle?
Antras join together –> shoots egg out
Granulosa cells continue to secrete follicular fluid (makes a continuous antrum around the oocyte –> mature follicle)
Granulosa cells around the oocyte = corona radiata
What happens when the hypothalamus detects low estrogen?
GnRH is released by the hypothalamus
What does GnRH do?
Gets LH and FSH released from the anterior pituitary
What does LH do?
Stimulates estrogen production (which inhibits GnRH/LH/FSH release)
*This doesn’t matter at this point bc the primary follicle just wants to grow
What happens when the primary follicle continues to grow?
Makes estrogen which stimulates GnRH/LH/FSH
What happens when LH surges?
Mature follicle ruptures + egg is released
What does the leftover follicle do after ovulation?
Converts itself into an endocrine gland (corpus luteum) which makes progesterone –> tells uterus to get ready for a zygote
Layers of the uterus
Myometrium
Endometrium (stratum basalis and then stratum functionalis)
Layers of the endometrium
Stratum basalis: always there
Stratum functionalis: gets thick & accepts fertilized egg, falls off