1. Menstrual Cycle
Mrs Teo CC

2. Stages of Menstrual Cycle
Menstruation
Repair and Growth of Uterine Lining
Ovulation
Further thickening of Uterine Lining

3. 1. Menstruation
If no fertilisation occurs after ovulation,
ovaries will stop producing hormones
ovum disintegrates
thick lining of uterus breaks down
broken lining, disintegrated egg and some blood flow out through the vagina – menstrual flow - marking the start of menstruation
menstruation lasts for about 5 days

4. 2. Repair and Growth of Uterine Lining (after menstruation)
after menstruation, ovaries release oestrogen into bloodstream
oestrogen causes growth and repair of uterine lining and blood capillaries to form within the thick lining - uterine wall becomes thick and spongy with blood vessels again

5. 3. Ovulation
occurs about the 14th day of the menstrual cycle
if fertilisation occurs - the female becomes pregnant
if no fertilisation occurs - menstruation occurs again 14 days after ovulation
for married couples who want to have children, sexual intercourse during period of ovulation is more likely to result in pregnancy

6. 4. Further thickening of Uterine Wall
after ovulation, ovary secretes progesterone into bloodstream
progesterone causes uterine lining to thicken further and becomes vascularised (contain many blood capillaries) - ready for implantation of embryo
if there is no fertilisation, uterine lining breaks down and menstruation starts again

7. Menstrual Cycle Start Uterine lining grows and thickens
Repair and growth of uterine lining
Uterine lining thickens further and becomes more vascular, preparing for implantation
Uterine lining breaks down and is discharged
Start

8. Thickness of Uterine Lining during Menstrual Cycle

9. Irregularities in menstrual cycle can be caused by:
 stress  emotional disturbances  mental fatigue  illness  unbalanced diet, malnutrition

10. The Fertile and Infertile phases
an ovum released during ovulation can live for days before it dies
sperm released into the female reproductive system can live for days
time from day 11 to fertile phase because fertilisation can occur during this period
rest of the days in the menstrual cycle - infertile phase because fertilisation is usually not possible during this period