Female reproductive system — A/L Biology

What must I remember about Female reproductive system?

• The female reproductive system consists of paired ovaries, Fallopian tubes (oviducts), uterus, vagina, and external genitalia (vulva: labia majora/minora, clitoris).
• Oogenesis begins before birth: primordial germ cells produce oogonia (2n), which initiate meiosis I to become primary oocytes (arrested at Prophase I until puberty); each month after puberty, one primary oocyte completes meiosis I forming a secondary oocyte (arrested at Metaphase II) and first polar body.
• The Uterus has three layers: outer perimetrium, thick muscular myometrium (contracts during labor), and inner glandular endometrium (stratum functionalis sheds during menstruation, stratum basalis regenerates it).
• The Ovarian Cycle has two phases separated by ovulation: Follicular phase (follicular growth driven by FSH, estrogen surge) and Luteal phase (corpus luteum secretes progesterone and estrogen, driven by LH).
• The Uterine (Menstrual) Cycle coordinates with ovarian cycle in three phases: Menstrual phase (days 1-5, shed endometrium), Proliferative phase (days 6-14, estrogen-driven endometrial regeneration), and Secretory phase (days 15-28, progesterone stimulates vascularization and glycogen secretion for embryo implantation).

Test yourself (1 minute)

1. LH Surge triggers Ovulation

   High sustained levels of estrogen at end of follicular phase switch from negative to positive feedback, triggering a massive spike in LH (and FSH) around day 14, rupturing the mature Graafian follicle.

2. Fate of Corpus Luteum

   If fertilization does not occur, LH drops, corpus luteum degenerates into Corpus Albicans, progesterone and estrogen crash, triggering endometrial breakdown (menstruation); if fertilization occurs, hCG from trophoblast rescues corpus luteum.

3. Fertilization site

   Occurs precisely in the Ampulla of the Fallopian tube; secondary oocyte completes meiosis II only upon sperm entry.

Practise Female reproductive system questions today

Source: NIE G.C.E. (A/L) Biology Syllabus & Resource Book, Unit 5

What should I study first?

What comes next?

Next in the syllabus

Where does Female reproductive system fit in the syllabus?

Year 2 · Term 1