4.6 pregnancy & 4.7 Childbirth

• Biologie
• Middelbare school
• havo
• Leerjaar 2

4.6 pregnancy & 4.7 Childbirth

But first some repetition

How do birds reproduce?

1. sexual reproduction
2. asexual reproduction

How does and apple tree reproduce, sexually or asexually?

1. sexual reproduction
2. asexual reproduction

What is the female reproductive hormone?

1. testosterone
2. oestrogen

Where do the ova mature and get ready to be fertilised?

1. in the uterus
2. in the vagina
3. in the oviducts
4. in the ovaries

Where does the embryo develop during pregnancy?

1. in the uterus
2. in the vagina
3. in the oviducts
4. in the ovaries

What is the names of the organ that holds the testes (testicles) outside of the male body?

1. penis
2. scrotum
3. sperm duct
4. stomach

Where are sperm cells produced?

1. in the penis
2. in the testicles
3. in the prostate
4. in the glans

Where is a man's urethra?

1. in the penis
2. in the testicles
3. in the prostate
4. in the glans

Where are liquids produced that are added to the semen?

1. in the penis
2. in the testicles
3. in the prostate
4. in the glans

4.6 pregnancy & 4.7 Childbirth

sperm vs egg

Sperm cells can survive for up to 4 days.

For fertilisation to occur, an egg cell must also be present in the fallopian tube.

An egg cell lives for approximately 12 to 24 hours after ovulation.

Getting pregnant

The egg cell must be fertilized by the sperm cell

Nucleus of the sperm cell must fuse with the nucleus of the egg cell

The fertilization

A nucleus of a sperm cell fuses with the nucleus of an egg cell,

this takes place in the fallopian tube.

Implantation: after about 6 days the ball of cells attaches itself to the thick uterine lining. Then the woman is pregnant

Fraternal Twins

• 2 egg cells are released at the same time. (2 ovulations happen)
• Each egg cell is fertilised by its own sperm cell (2 separate fertilisations happen)
• Each zygote will develop into an embryo
• Each zygote has its own DNA
• They can look similar but usually don't have to
• Their sex can be the same or different

Identical twins

• Only 1 egg cell is released during ovulation
• That egg cell is fertilized by 1 sperm cell
• After the first (few) cell division(s) the cells are split into separate clumps of cells
• Both groups of cells will develop into an embryo. 
• They will have the exact same DNA
• They will look similar and always be of the same sex

It is not possible for 2 (or more) sperm cells to fertilize 1 egg cell! 

If this were to happen the egg cell will not be able to develop and will die.

!

Pregnancy

0-8 weeks: Embryo

8 weeks to birth: Fetus

The placenta provides oxygen and nutrients and removes waste such as carbon dioxide so that it can be excreted by the mother.

Placenta

The placenta grows at the place where the embryo is implanted. The placenta contains capillaries (very thin blood vessels where gas exchange can take place).

Amniotic fluid and amniotic membranes protect the unborn child.

Amniotic membranes

Amniotic fluid

Prenatal testing

• 8-12 weeks: Ultrasound: Determine how long the woman has been pregnant
  
• From 10 weeks: NIPT test (non-invasive prenatal test) --> blood test (child's DNA) for DNA abnormalities.
  
• 13 weeks --> ultrasound for examination of abnormalities in the heart, brain, organs and limbs
  
• 20 weeks --> ultrasound (check) and gender can be determined

4 stages of labour

Contractions --> muscles in the uterus contracts

Dilation --> cervix opening becomes wider

Expulsion --> baby is born

Afterbirth --> Placenta is pushed out

 

Make questions from 4.6 & 4.7 in your workbook