F1-Science, Chapter 4 - 4.3

CHAPTER 4:
Reproduction

4.3 THE MENSTRUAL CYCLE

menstrual cycle???

menstruation???

MENSTRUATION When women reach puberty

MENSTRUATION

Breakdown of the lining

of the uterine wall and

discharge of blood

through the vagina

FEMALE REPRODUCTION SYSTEM

Ovary and ovum



1. Controlled by the brain and endocrine system
- Secrete hormone

2. Lasts for 28 days (differs for each individual)

3. Factors that affect the menstrual cycle
• Nutrient intake
• Abrupt change in body weight
• Emotional changes and mental pressure

MENSTRUAL CYCLE

- Series of changes that
occurs in the uterine
wall and the ovaries

- Involve formation and
release of mature
ovum

4 PHASE

1.

MENSTRUATION PHASE
day 1-5

- Uterine lining  breaks down (menstruation)
- Discharged together (blood, unfertilized ovum and mucus)

2.

REPAIR PHASE
day 6-11

- Uterine lining  starts to rebuild and thicken
- Blood vessels form
- Ready to receive implantation of fertilized ovum

3.

FERTILE PHASE
day 12-17

- Ovum released (14th day)  OVULATION
- Uterine lining  continues thicken
- Fertilisation occur  if sperms are present

4.

PREMENSTRUAL PHASE
day 18-28

- Uterine lining  thicken/richly supplied with blood vessel
- if fertilisation occur  Ready for implantation of an embryo
- If fertilization not occur menstrual cycle will repeat

MENSTRUAL
CYCLE

Importance of personal hygiene
during menstruation

- Ensure reproductive
system is not infected
with microorganisms
like bacteria, virus and
fungi

1. Change sanitary pad 3-4 times a day 
prevent infection of bacteria and virus

2. Menstruating women  bathe frequently

IRREGULAR MENSTRUATION

(negative effect)

- Infertility (eg: ovarian cancer, uterus cancer)
- Difficulties in family planning
- Health problem (eg: anaemia)