menstrual cycle

1.  The events in the menstrual cycle are :

2. stage 1 - Follicle stage
 The anterior pituitary produces FSH which is
carried to the ovary where it stimulates
development of one or more graafian follicle

3. Stage 2 - Ovulation
 Increased estrogen from
the follicle
1.Stimulates the pituitary
gland to produce LH and
inhibits FSH
2.Repair and thickening of
endometrium

4. Stage 3 – Corpus Luteum
 LH surge occurs on day
12 triggering ovulation
 The ruptured follicle
heals inside the ovary
forming the corpus
luteum
 Yellow body
 The corpus luteum
produces progesterone
 Reduced amount of
oestrogen produced

5.  Negative feedback –
Progesterone and oestrogen inhibits FSH and
LH and stimulates growth and blood supply of
endometrium.

6. Stage 4 - Menstruation
 If an embryo is not present approximately 2
weeks after ovulation the corpus luteum
decomposes
 Estrogen and progesterone levels decrease
 FSH is not inhibited and is secreted by
pituitary.
 Endometrium breaks resulting in
menstruation

7. If pregnancy occurs….
 Corpus luteum released
 Progesterone & oestrogen levels are high
 Womb lining is intact
 FSH production is inhibited

8. Menstrual cycle