Fertilisation and Pregnancy

• Biologie
• Middelbare school
• vwo
• Leerjaar 4

Fertilisation and Pregnancy

Learning Objectives

• Describe the hormonal changes that occur if fertilisation happens
• Describe the hormones involved in pregnancy
• Describe important stages during pregnancy

During which days of a 28 days menstrual cycle does the follicular phase occur?

1. 1-13
2. 14-17
3. 14-28
4. 0-5

Where does fertilisation occur?

1. Ovary
2. Uterus
3. Vagina
4. Fallopian tube

Which hormone is released from the pituitary gland that stimulates the follicles in the ovary to mature?

1. Progesterone
2. GnRH
3. FSH
4. Oestrogen

What causes the menstruation to start when the egg is not fertilized?

1. Peak in progesterone
2. Peak in oestrogen
3. Lack of progesterone
4. Lack of oestrogen

Fertilisation

• Sperm cells carry enzymes
• Egg cell create permanent block
• Egg cell completes meiosis II

Pregnancy - first period

• Meiosis completes
• Cleavage divisions
• Blastocyst
• Implantation

Assignment

What are the key hormones in pregnancy?

Which organs are involved in their production?

Which role do these hormones have during the pregnancy? 

Placental development

The roles of placenta

• Nutritional (provides oxygen, glucose, amino acid transfer)
• Immunologic (protects the fetus from pathogens and the maternal immune system)
• Endocrinologic (produces hormones)
• Metabolic (serves as the respiratory and the kidney organ for the fetus)

Birth

• First stage:
  

- Cervix expands

- Amniotic fluid released

• Second stage: delivery
  

- Actual birth

• Third stage:
  

- Expulsion of the placenta

Lactation

• Nourishment after birth
• Hormones
  

- Prolactin: promotes milk production

- Oxitocyn: stimulates release of milk

• Drinking baby promotes release of prolactin and oxytocin, but inhibits release of LH and FSH
  

- Lactational anovulation

• Colostrum: first milk, contains many antibodies

Which of these hormones does not increase during pregnancy?

1. FSH
2. Progesterone
3. HCG
4. Oestrogen

Which of these hormones stimulates lactation?

1. FSH
2. Oxytocin
3. HCG
4. LH

Your school friend just did a pregnancy test. The result of the test is positive. Which hormone has been then detected?

1. The presence of progesterone
2. The presence of human chorionic gonadotropin

Homework:

Read the book: pages 123-125