Mestrual Cycle

Question 1

Definition of menstruation

Answer 1

Uterine lining breaks down and flows from the uterus, out of the body, through the vagina

Question 2

Definition of ovulation

Answer 2

Release of mature ovum from the ovary

Question 3

During ovulation, …

Answer 3

1. Changes in the thickness of the uterine lining
2. Changes in concentrations of female sex hormones (progesterone and oestrogen) in the blood

Question 4

Duration of menstrual cycle

Answer 4

Average is 28 days

Question 5

Roles of female sex hormones in the menstrual cycle

Answer 5

Low oestrogen and progesterone levels +
1. can cause menstruation (break down of uterine lining)
High oestrogen levels +
1. cause repair and growth of uterine lining
2. indirectly leads to ovulation
High progesterone levels +
1. maintains the thickness of the uterine lining
2. prevents ovulation from occurring again

Question 6

Describe the menstrual cycle

Answer 6

1. From [Day 0 to Day 5]
   - low levels of oestrogen and progesterone causes
   - menstruation where uterine lining breaks down +
   - thickness of uterine lining drastically decreases
2. From [Day 6 to Day 13]
   - oestrogen levels increase (peak on day 12)
   - high levels of oestrogen causes
   - uterine lining to repair and grow +
   - thickness of uterine lining gradually increases

[On Day 14]
- high levels of oestrogen indirectly causes
- ovulation where a mature ovum is released from ovary

From [Day 14 to Day 28]
- progesterone levels increase (peak on day 23)
- high levels of progesterone causes
- uterine lining to be maintained +
- thickness of uterine lining remains high
- prevents ovulation from occurring again