1. Menstruation
IF fertilization does NOT take place
Menstrual cycle – a series of changes controlled by hormones that help prepare the female uterus for a possible pregnancy
The cycle is controlled by hormones of the pituitary gland and ovaries
The menstrual cycle occurs in 4 stages

2. Ova maturing in a Follicle

3. stage 1 - Follicle stage
Ovarian hormones (estrogen and progesterone) are in low concentrations
The pituitary gland produces FOLLICLE STIMULATING HORMONE (FSH) which causes a follicle (egg cell capsule) to form
As the follicle grows it makes increased amounts of estrogen

4. Stage 2 - Ovulation
Increased oestrogen from the follicle stimulates the pituitary gland to produce Luteinizing hormone(LH)(controls ovulation and forms the corpus luteum)
The LH surge causes the follicle to rupture and the egg cell is sent to the oviduct

5. Stage 3 – Corpus Luteum
The ruptured follicle heals inside the ovary forming the corpus luteum
Also called a Yellow body
The corpus luteum produces progesterone(another hormone)
Estrogen and progesterone maintains the added growth of the uterine lining

6. Stage 4 - Menstruation
A fertilization is possible only within the first 24 hours after ovulation. If the ovum does not encounter any sperm cells during this time, it simply dies and disintegrates
THEREFORE ,if an embryo is not present approximately 2 weeks after ovulation the corpus luteum decomposes
Estrogen and progesterone levels decrease
The lining of the uterus is shed and moves out through the vagina( PERIOD)

7. Stage 4 - Menstruation