Fertilisation and pregnancy

• Biologie
• Middelbare school
• vwo
• Leerjaar 4

Reproduction

Fertilisation & pregnancy

Today

- Questions last lesson

- Explanation fertilization & pregnancy

- Do assignments

Questions

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

- If the ovum is to be fertilised, where is the most common site of fertilisation?

- What hormone is released from the pituitary gland and stimulates the follicles in the ovary to mature?

- If the ovum is not fertilised, what causes the cycle to end and menstruation to start?

Learning objectives

• You can describe the hormonal changes that occur after fertilisation happens
• You can describe the hormones involved in pregnancy
• You can explain how the placenta functions
• Describe the important stages during pregnancy 

Write down for yourself what you see during this video!

Questions about the video?

Fertilisation

• Sperm cells carry enzymes
  
  
• Egg cell puts up permanent block
  
  
• Egg cell completes meiosis 2
  

First period of pregnancy

• Completion meiosis
• Cleavage divisions
  - No growth
• Blastocyst
  - First structures
• Implantation

First period of pregnancy

• Cleavage divisions
  - No growth
• Blastocyst
  - First structures
• Implantation

Implantation

• Embryo gets nutrients from the endometrium
• The trophoblast invades the endometrium
• The placenta is being formed

Placenta development

• Formed by embryo and mother together
• Exchange of nutrients and waste
• No direct blood contact!

Exchange of nutrients/ waste/O2

• O2, CO2 , nutrients  and wastes via diffusion, selective absorption and active transport
  
• between the fetal capillary beds and the maternal blood spaces
  
• No mixing of blood!

What arteries and veins?

• One umbilical vein containing O2 rich, CO2 poor, nutrient rich blood
• Two umbilical arteries containing O2 poor, CO2 rich, nutrient poor and waste rich blood

The Cuddle Hormone Oxytocin

- Okytokos: Greek for quick birth

- stimulates the contractions

-made by the posterior lob of the pituitary gland

- is being released by both men and women when they cuddle and or have sex

-increases chances on fertilization

- helps parents to bond with their child

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
    - Oxytocin: stimulates release milk

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

    - Lactational anovulation

• Colostrum: first milk contains many antibodies

Questions

What are the three hormones that increase during pregnancy?

What hormone stimulates lactation?

What is the hormone that you can detect with a pregnancy test?

Work to be done

Assessment Questions Glencoe pg 1069-1070: Q 12-22.

Assessment Questions Glencoe pg 1070 Q: 25-34 +36.

 - Make a summary for yourself in which you describe

all the stages from fertilization to labour (include hormones)

- Do the LessonUp on sexual Diversity (Teams)