Physiology 3120 Lecture Notes - Lecture 4: Glycogen, Epiphyseal Plate, Corpus Luteum
9 May 2018
School
Department
Course
Professor
Physiology 3120
Dr. Regnault
Lecture 4
Folliculogenesis
- Corpus luteum
o Remnant of follicle
o Lipid rich
o LH surge = P4
- Rising estrogen levels, you start to see LH and FSH decline
o This is associated with developing secondary Graafian follicle which secretes more
estrogen
o This causes –ive feedback to LH and FSH
- Prior to ovulation, something flips
o With the pre-ovulatory follicle, high estrogen levels play a feedforward mechanism on
the hypothalamus and pituitary
o This feedforward mechanism is associated with an increase in the pulse generator
activity (more frequent pulses and an increase in amplitude) this is associated with
LH secretion
o Also, the sensitivity to GnRH with more GnRH receptors occurs on the pituitary
o So not only is the pulse changing but the receptivity to those pulses is also increasing
o This is why we see a massive rise in LH
(feedforward mechanism)
- In the luteal phase,
o We move back to a –ive feedback driven by
mainly progesterone and a little bit of
estrogen, shutting down the production of LH
and FSH
find more resources at oneclass.com
find more resources at oneclass.com
- 2 layers of the uterus:
o endometrium
▪ where the egg is embedded
▪ has 2 layers:
• stratum functionalis
o has lots of secretory glands
• stratum basalis
o has lots of blood vessels
o myometrium
▪ muscular wall on outside
- bottom row is the endometrium, which as 2 phases during the 28 cycle:
o proliferative phase
▪ occurs under follicular development
▪ has 2 phases:
• menses phase
o shedding of the endometrial layer
o this breakdown occurs under low estrogen and low
progesterone
• proliferative phase
o really starts up where the endometrium really starts to grow
o as we move through the proliferative phase, estrogen levels
start to rise and one of estrogens many jobs is the development
of the endometrium
o through estrogens actions, it promotes things like blood vessel
development (especially in the stratum basalis) and
development of the stratum functionalis cells through mitosis
(rapid division)
o secretory phase
▪ occurs during the development of the corpus luteum during the luteal phase
▪ this phase is after ovulation
▪ gonadotropins expression is 0
▪ estrogen does a little dip
▪ progesterone increases
▪ during this phase, there is maximum secretions occurring from the stratum
functionalis cells which has undergone rapid divisions bc of estrogen
▪ but then progesterone promotes differentiation of these cells and function
(secretion of various hormones and growth factors in preparation for
implantation)
▪ here, estrogen is also involved in muscular contractions (cause of period
cramps)
find more resources at oneclass.com
find more resources at oneclass.com
