2. Physiology of menstruationthe ovaries... 1. Hypothalamus releases GnRH (LHRH) 2. Release of GnRH triggers APG to release FSH and LH FSH- responsible for the maturation of ovum and follicle formation. Causes an increase in estrogen LH – triggers ovulation and growth of uterine lining
3. 2.1 FSH activates primordial follicles to mature. 2.2 Primordial follicles start producing follicular fluid that is HIGH IN ESTROGEN (estradiol) and some progesterone 2.3 primordial follicles propelled toward the surface of ovary and is now called Graafian Follicle. 3. Graafian follicle undergoes cell division (mitosis, meiosis) 3.1 GF divides into: 3.1.a primary oocyte – with more cytoplasm 3.1.b secondary oocyte – with less cytoplasm 3.2 GF after meiosis contain haploid cells (23 chromosomes)
4. 4. Upsurge in LH causes the release of prostaglandin 5. Prostaglandin causes the rupture of GF releasing ovum and follicular fluid from the follicle, leaving the follicle with a hollowed pit. 6. Increase in LH causes production of Lutein (bright yellow fluid, HIGH IN PROGESTERONE) that will fill the empty pit 7. Follicle becomes “CORPUS LUTEUM”
5. 7.1 if fertilization occurs, ovum implants at the uterus, corpus luteum stays inside the ovaries until 16-20 weeks; trophoblast begin secreting HCG 7.2 without fertilization, ovum atrophies after 4-5 days, CL remains for only 8-10 days. 7.2.a CL replaced by white fibrous tissue, CL becomes “CORPUS ALBICANS”
