Bricks 4.4 Menstrual cycle

• Biologie
• Middelbare school
• vwo
• Leerjaar 1

4.4 Menstrual cycle

Learning goals 4.4

1. You know what ovulation is
2. You can explain what menstruation is
3. You know when these processes happen in the menstrual cycle
4. You know how 4 hormones: FSH, LH, oestrogen and progesterone regulate the menstrual cycle

What is ovulation?

-Egg cell (ovum) is released from the ovary

-Unfertilized egg cell lives from 12 and 24 hours.

-After 24 hours the ovum will die and be absorbed into the bloodstream.

What is menstruation?

• Release of blood from the uterus lining through the vagina
• Happens only if egg cell is not fertilized
• Start around age 12

How does it happen? 

• Hormones oestrogen en progesterone build up uterus lining
  
  
• Fertilized egg could attach to this
  
  
• No fertilized egg? --> Lining is shed
  
  
• cylce: it happens over and over again (450 times in a life time)

Menstrual cycle

• The menstrual cycle is the process that the female sex organs go through each month again; preparing an egg for fertilisation, and getting rid of it when it is not fertilised.

• This whole process is regulated by hormones

• This cycle generally lasts somewhere between 21 to 35 days, on average it is 28 days (that is why we normally count in months)

28 days = 4 weeks

3 Phases

Phase 1 (day 1-5) : menstruation

• Uterus lining is shed through the vagina (no fertilized egg)
  
  

Phase 2 (day 6-12): pre-ovulation 

• repair phase: uterus lining build new layer of mucus
• new egg cell develops in the ovary

3 Phases

Ovulation (day 13-15)

• A new ova is released and send down the oviduct
  
  

Phase 3: post-ovulation (day 16 - 28)

• Uterus lining grows to form a 'nest' for the egg cell
• No fertilized egg cell? --> cycle starts again!

Menstrual cycle

oestrogen

oestrogen

What determines the beginning of the menstruation cycle?

1. Release of blood through the vagina
2. The release of the egg cell from the ovaries
3. The growing of the uterus lining
4. The cycle can start anytime

In which part of the female reproductive system do the ova (egg cells) develop?

1. Fallopian tube/Oviduct
2. Ovaries
3. Uterus
4. Vagina

In which part of the female reproductive system does the fertilised egg cell grow into a baby?

1. Fallopian tube/Oviduct
2. Ovaries
3. Uterus
4. Vagina

On which day in the cycle does ovulation occur?

1. Day 1
2. Day 14
3. Day 20
4. Day 28

What is shed during the menstruation of a female?

1. The ovaries
2. The egg cell
3. The uterus lining
4. Nothing

How long does an released egg cell survive?

1. 15 days
2. 4 days
3. about an hour
4. 1-2 days

The cycle is for everyone the same. It is always 28 days.

1. True
2. False

How do we call the release of an egg cell into the oviduct?

1. Fertilization
2. Ovulation
3. Pregnancy
4. Contraceptive

Anne her period starts at the 10th of May. When is it most likely her ovulation occurs?

1. May 14th
2. June 14th
3. May 24th
4. June 24th