Lecture Notes on Male and Female Reproductive Physiology

• The ovarian and menstrual cycles are two coordinated monthly processes in the female reproductive system, where the ovarian cycle develops an egg in the ovary (follicular phase, ovulation, luteal phase), and the uterine (menstrual) cycle prepares the uterus lining (proliferative, secretory, menstrual phases) for potential pregnancy, all regulated by hormones like FSH, LH, estrogen, and progesterone, typically around 28 days.
• These cycles run in parallel: the ovarian follicular phase aligns with the uterine proliferative phase, and the ovarian luteal phase with the uterine secretory phase, ending in menstruation if no pregnancy occurs

Ovarian Cycle Phases (Ovary)

1. Follicular Phase: FSH & LH stimulate follicles to grow, producing estrogen. One becomes dominant.
2. Ovulation: A surge in LH causes the dominant follicle to rupture, releasing the egg (around day 14).
3. Luteal Phase: The ruptured follicle becomes the corpus luteum, producing progesterone and estrogen to ready the uterus. If no pregnancy, it degenerates. 

1. Menstrual Phase: Low hormone levels cause the uterine lining (endometrium) to shed (period).
2. Proliferative Phase: Rising estrogen rebuilds the endometrium.
3. Secretory Phase: Progesterone (from corpus luteum) makes the lining rich in glands and blood vessels, ready for implantation. 

• FSH (Follicle-Stimulating Hormone): Stimulates follicle growth.
• LH (Luteinizing Hormone): Triggers ovulation (LH surge).
• Estrogen: Thickens the uterine lining; high levels trigger LH surge.
• Progesterone: Maintains the uterine lining for pregnancy. 

• Beginning: Day 1 of menstruation marks the start of both cycles.
• Correlation: Ovarian follicular phase = Menstrual & Proliferative phases; Ovarian luteal phase = Secretory phase.
• End: Hormone drop (estrogen/progesterone) causes the corpus luteum to degenerate, leading to menstruation and a new cycle