Ovarian and/ Menstrual

Cycles

Ovarian Cycle

• Series of events in the ovary• Maturation of egg & release to fallopian tube• Approx: 20 – 40 day period (Ave 28 days)• At birth, ovaries (2) have 400, 000 immature eggs

• *Steps 1-4 take approx 10 – 14 days

Ovarian CycleStages:1. Primary follicle : egg is surrounded by other cells

2. Secondary follicle: cells enlarge and secrete fluid, forcing egg to the edge of the follicle

3.Graafian Follicle: follicle fills with more fluid, enlarges and produces a bulge on the surface of the ovary

4. Ovulation: follicle bursts, expels egg into fallopian tube

Ovarian CycleStages:5. Corpus Luteum: Ruptured Graafian follicle collapses, blood inside forms a clot. Clot is absorbed & follicle turns a cream / yellow colour

6. a. Fertilisation: Corpus Luteum continues to develop & secretes hormones for endometrium development (last approx 3 months)

b. No fertilisation: by 8-10 days, Corpus Luteum degenerates into Corpus Albicans (scar tissue)

MENSTRUAL Cycle• Series of events in endometrium (lining of the Uterus)• Very closely related to ovarian cycle (28 days) Stages:1. endometrium becomes thicker and softer.• Increase blood vessels and mucous membrane

2. continues to thicken• glands secret watery mucus (high in glycogen). • Assists sperm travel

  ovulation

MENSTRUAL Cycle

 ovulation 3. Corpus Luteum degenerates endometrium degenerates menstruationApprox 14 days after ovulation

* Steps 1-2 take approx 10 – 14 days