38) Anatomical & Physiological Characteristics of Female Genitals; Neuro-Hormonal Regulation of Menstrual Cycle Flashcards
Explain the Anatomy / Physiology of Female Genitals?
1) External
- Vulva = Mons Pubis, Labia Majora + Minora, Clitoris, Vestibule
- Bartholin Glands = Found on BOTH SIDES of Vaginal Opening
2) Internal
- Uterus = Fundus, Body + Cervix (NARROW PART opens into Vagina)
- Fallopian Tubes
- Ovaries
What is the Definition of “Menstrual Cycle”?
- Physiological Process which coordinates hormone release from Hypothalamus, PG + Gonads
- Lasts 24 - 38 Days
MENSES = 3 - 7 Days / 35 - 50ml
What are the Phases of the Menstrual Cycle?
1) Follicular Phase (Day 1)
2) Ovulation (Day 14)
3) Luteal Phase (Ovulation – Next Period)
Describe the Follicular Phase
1) Hypothalamus secretes Gonadotropin-RH, stimulating ANTERIOR PG –> Releasing FSH / LH
2) FSH stimulates GRANULOSA CELLS (Ovaries) –> Releasing Estradiol / Inhibin-B
3) LH stimulates THECA CELLS (Ovaries) –> Releasing Progesterone
4) Follicle MATURATION –> *Estradiol Secretion from DOMINANT Follicle
5) TRIGGERS Positive Feedback on PG –> SURGE in LH –> OVULATION
Describe Ovulation
1) LH SURGE causes Ovulation —> Release of MATURE Oocyte
2) DOMINANT Follicle –> CORPUS LUTEUM ; Release of PROGESTERONE
3) Progesterone INHIBITS LH Secretion
Describe the Luteal Phase
1) There’s DECREASE in LH Levels –> DEGENERATION of CORPUS LUTEUM
2) This means REDUCED Production of Progesterone + Estradiol
3) This Signals ONSET of MENSTRUATION
Explain the Uterine Cycle
1) MENSES (Days 1 - 7)
- Happens 14 Days AFTER OVULATION
- Degeneration of Corpus Luteum –> Reduced PROGESTERONE –> Vasospasms in Uterine SPIRAL ARTERIES
2) PROLIFERATIVE PHASE (Days 7 - 14)
- Estradiol secretion —> promotes THICKENING of Endometrium, for IMPLANTATION
3) SECRETORY PHASE (Days 14 - 28)
- DIFFERENTIATION of Endometrium, getting ready for implantation
