4.4 Becoming pregnant 2HVTTO

• Biologie
• Middelbare school
• havo, vwo
• Leerjaar 2

B4 Becoming pregnant

• Jacket in your locker
• Put your things on your desk

       Laptop/Book

       Notebook, pencil case

• Bag on the floor
  
• Read pages 36-41

Lessongoals

• Remember: I can name the characteristics of sperm cells and egg cells by correctly describing their structure and function.
• Understand: I can describe the fertilization of a human egg cell by explaining how sperm and egg meet and combine genetic material.
• Understand: I can describe how a pregnancy progresses by explaining the stages of development from fertilization to birth.
• Apply: I can explain what a prenatal investigation is and give examples by describing different types of tests and their purposes.

Homework U4 B4

Wheel of homework

Go to Lessonup.app and use this code

Reward

Penalty

Rewards

• +1 cm2 cheatsheet = you get to make a cheatsheet for a test. This starts being 1 by 1 cm. Everytime you earn this it gets 1 cm bigger to a max of 4 by 4 cm.
• 1/3 +0.5 = If you earn this 3 times you get to add 0,5 to one of your biology marks.
• Snitch = You can pick a classmate who also is checked for homework, you earn two V's (having 3 earns you a 1/3 +0,5)
• Too bad = You only get one V
  

penalties

• 45 min extra worktime = you need to come after school and do homework, this will last for 45 min or until the task is done
• Coloringpage = You get to pick a coloringpage, You need to color it and perform tasks that might be on it. You need to hand it in during the next lesson, If you don't you get 2 marks.
• 2/1 marks = a mark is an X, if you get 3 of these you will automaticly earn the 45 min extra worktime.
• Snitch = You can pick a classmate who also is checked for homework
• Lucky! = You don't get a penalty

Often an egg cell is not fertilized.
What will happen?

1. It returns to the ovary
2. It dies in the falopian tube and is absorbed
3. It dies in the uterus and is absorbed
4. It dies in falopian tube or uterus and comes out during menstruation

What is the function of the testes?

1. make sperm cells
2. store sperm cells
3. make sperm
4. store sperm

What part is mainly responsible for making a man orgasm?

1. ballsack
2. penis
3. erectile tissue
4. glans

Which part of the male and female reproductive organ have a similar function?

1. ovary and testes
2. erectile tissue♂ and vagina
3. vagina and urethra♂
4. seminal vesicle and ovary

Sex cells

Sperm cells 

• Millions produced each day
• Smallest human cell
• Tail for movement
• Head contains DNA

Egg cell

• About 1 egg cell released each month
• Biggest human cell
• Contains lots of reserves
• Can't move on its own

Sperm- and egg cells (pictured)

An ejaculation

Sperm comes out of the penis (with force)

• During sex/inter course
• During masturbation
• When aroused (especially during puberty)
• Wet dream (especially during puberty)
• At any moment (especially during puberty)

During/before sex erectile tissue in the penis fills with blood.

A man gets an erection/'boner'.

In a woman the same happens in erectile tissue of the clitoris

An erection makes it easier to put the penis into the vagina and make an orgasm happen.

Usually before ejaculation some liquid comes out of the penis. This works like a lubricant.

The 'erection' of the clitoris helps guide the penis. This makes it easier to go into the vagina.

The labia will produce a liquid that works as a lubricant

ODOL/morning wood

Why an Erection in the Morning?

• Body control during sleep – Your body has an automatic system that functions while you sleep, regulating things like heart rate, digestion, and erections.
• Sleep and hormones – Erections occur multiple times during the night, especially during REM sleep, due to hormonal changes and increased blood flow.
• Other causes – A full bladder can press on a nerve that triggers an erection, and sometimes movement during sleep can also cause it.

1

Sperm enters the female body 

♂

2

Sperm swims through the uterus, towards the fallopian tubes.

♂

3

1 sperm cell can fertillize the egg cell, the others die

Without an egg cell the sperm will die

♂

1

an ovum (egg cell) is released from the ovary = ovulation

♀

2

Egg cell is fertilized by sperm cells and starts cell division.

OR

Egg cell is not fertilized and dies in fallopian tube

♀

3

the fertiziled egg cell starts cell division

♀

4

Implantation of the fertilized egg cell, pregnancy has begun.

♀

fallopian tube

fertilization

ovulation

ovary

implantation

thick mucous lining

uterine wall

cervix

opening of uterus

Ovulation = The moment an egg cell is released from an ovary.

Inside ovaries egg cells are maturing, once this is done they are released

Fertilization = The moment an egg cell and sperm cell become one.

This creates a fertilized egg cell, which will develop into an embryo

inside the uterus, a thick mucous layer grows. also called the inner lining.

It's main function is to give nutrients to a fertilized egg cell to help it develop

Fertilization

Only 1 sperm cell will penetrate the membrane of the egg cell

Directly after the first sperm cell penetrates the membrane, a layer will form around the egg cell. This makes sure no other sperm cells can go in.

impermeable = not allowing anything in or pass through

The nuclei of sperm cell and egg cell become one.

This creates the DNA of the new human

The moment when 1 sperm cell and 1 egg cell become one = fertilization.

After this you get a fertilized egg cell that will imediately start dividing.

Twins?

Twins can happen in 2 ways:

Identical = one egg cell is fertilized by 1 sperm cell, after the first cell division the cells are split, meaning that both groups of cells will develop.

Non-identical = 2 egg cells are released at the same time in the body. Both are fertilized and develop.

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.

!

How long does the average pregnancy take?

Read and answer

Do this assignment alone or in pairs.

Write the answers in your notebook.

1. Use pages 38 to 41 from the book.
2. Use this information + previously learned knowledge to answer the questions.
3. Write both the questions and answers in your notebook.
4. Finished early? Start on the homework.

Questions

1. How does an embryo receive nutrients at the beginning of pregnancy (when there is no placenta yet)?
2. How does the placenta enable the embryo to receive food and oxygen?
3. Why is the embryo enclosed in a fluid-filled sac?
4. Describe 4 ways in which the development of the embryo is monitored.

Homework U4 B4

Asgmt. 1-9, 4c

OR challenge

Asgmt. 5-11

1. How does an embryo receive nutrients at the beginning of pregnancy (when there is no placenta yet)?

During the first few week the inner lining of the uterus provides nutrients to the developing egg cell. This later becomes the placenta.

Start of pregnancy

Placenta

2. How does the placenta enable the embryo to receive food and oxygen?

Blood vessels of the foetus go through the umbilical cord to the placenta.

In the placenta blood of mother and foetus flow close near each other, here nutrients, oxygen and waste is exchanged.

Blood of the mother does not go into the baby (or the other way around!)

Placenta

3. Why is the embryo enclosed in a fluid-filled sac?

The amniotic fluid has a few tasks:

• Protect against dehydration
• Protect against knocks/bumps (when mother accidentaly bumps into something or falls)
• Prevent quick changes in temperature

Amniotic membranes and fluid

Describe 4 ways in which the development of the embryo is monitored.

The development is closely monitored in the following ways:

Ultrasound-scan = using soundwaves to see the child

• Due-date scan = Deciding when baby will be born
• Anomaly scan = Check for abnormalities in development of organs
• 20 weeks scan= check for problems, tell sex of baby
• Extra scans = extra, to see the child

Prenatal investigation = Look for possible problems, confirm sex

• NIPT = check for hereditary diseases/abnormalities

What you should do: U4 B4

• Pages 36-46
  
• Asgmt 1-9, 4c
  

OR challenge

• Asgmt 5-11

Done with the above?

• Work on the next chapter(s)
• Learn for the test 
• Make other homework
• Read a book

Zs = Working in Silence

• No asking questions
• Silent, don't disturb anyone
  
• Stay at your  desk

What you should do: U4 B4

• Pages 36-46
• Asgmt 1-9, 4c

OR challenge

• Asgmt 5-11

Done with the above?

• Work on the next chapter(s)
• Learn for the test 
• Make other homework
• Read a book

Zw = Working with whispering

• Teacher is available for questions
• Only whisper with the student next to you
• Stay at your  desk

Some people say that the placenta and inner lining of the uterus are the same.
Is this correct? Why (not)

Tidy Duty

3 people each lesson

• Desks: empty and straight
• Chairs:  underneath the desks OR end of day: on the desks
• Floor: no rubbish