Fertilisation. Reproduction and Growth . Keywords Fertilisation Sperm Egg Zygote Embryo Cell division Implantation. Learning Objectives. Review what happens in fertilisation Describe the stages that occur after fertilisation Explain how an embryo develops.
Fertilisation Reproduction and Growth Keywords Fertilisation Sperm Egg Zygote Embryo Cell division Implantation
Learning Objectives • Review what happens in fertilisation • Describe the stages that occur after fertilisation • Explain how an embryo develops
What is fertilisation? When the sperm and the egg FUSE together.
A nucleus contains chromosomes The nucleus contains the chromosomes which carry your DNA.
Where did you get your chromosomes from? You got half of your chromosomes from your mum and half from your dad Who did you inherit you eye colour from? Nose shape? Hair colour?
Draw this diagram in your books Can you explain what this diagram shows? What is the name of this process?
What happens to the zygote? After fertilisation the zygote continues to move down the fallopian tube/oviduct to the uterus
What happens to the zygote? The fertilised egg (zygote) then divides and copies itself several times. It then becomes a ball of cells called an embryo.
Passing on the instructions Use the keywords to identify the key stages on the worksheet.
What happens in the womb? Lining of womb/uterus thickens ready to receive the embryo
Implantation Embryo attaches itself to the uterus wall. This is called IMPLANTATION.
Today we will learn about foetal development and pregnancy Keywords: Zygote Embryo Umbilical cord Foetus Oxygen Carbon dioxide Glucose
Fill in the missing words During sex the man's _______ releases semen into the woman's _________. Sperm cells travel from the penis and into the top of the vagina. They enter the ________ through the cervix and travel to the __________. If a sperm cell meets with an egg cell there, _________ can occur. Fertilisation happens when an egg ______ meets with a ______ cell and joins with it. The fertilised egg divides to form a ________ called an __________. This ________ to the lining of the uterus and begins to develop into a ________ and finally a baby.
Learning Objectives • Identify the key stages during • pregnancy • Recognise how a foetus develops • and identify the key stages during • pregnancy • Describe how the mother and • baby exchanges substances
Pregnancy – this is when a baby grows inside a woman. The baby grows inside the womb (the uterus). It is protected by a bag of water, and gets food from the woman through the placenta.
What happens after fertilisation? (video) http://www.youtube.com/watch?v=gaK0VPV9NlE&list=PLabyujw8qBzqQxWXslp9ml2w0E-Nw-vrk
What happens after fertilisation? The zygote (fertilised egg) divides and copies itself. This is called an embryo. The embryo floats towards the uterus.
3 - 5 weeks Weeks 3-5 The embryo’s tiny heart begins to beat by day twenty-one. Arm and leg buds are visible and the formation of the eyes, lips, and nose has begun. The spinal cord grows faster than the rest of the body giving a tail like appearance which disappears as the embryo continues to grow. The placenta begins to provide nourishment for the embryo.
7 weeks Week 7 - Major organs have all begun to form. The embryo has developed its own blood type, unique from the mother’s. Hair follicles and knees and elbows are visible.
8 - 12 weeks Weeks 8-12 The embryo is reactive to its environment inside the amniotic sac where it swims and moves. Hands and feet can be seen.
13 - 16 weeks Weeks 13-16 The brain is fully developed and the foetus can suck, swallow, and make irregular breathing sounds. Foetus can feel pain.
20 - 24 weeks Weeks 20-24 Foetus has a hand and footprints and fingerprints are forming. Foetus practices breathing by inhaling amniotic fluid into its developing lungs.
25 - 28 weeks Weeks 25-28 Rapid brain development occurs during this period and the nervous system is able to control some bodily functions. The foetus’ eyelids now open and close. At 25 weeks there is a 60% chance of survival if born.
29 - 32 weeks Weeks 29–32 There is a rapid increase in the amount of body fat the foetus has. At this point there the survival rate is above 95% if the baby is born.
40 weeks Week 40 Baby is fully developed and ready to be born.
Task - Pregnancy worksheet Name: _______________ Write the correct statement next to the correct picture. Week 8 Week 10 Week 20 Week 30 Week 40
Write the correct statement next to the correct picture The embryo is now called a foetus and has human features The foetus is 30cm long and the brain is very active. The foetus sleeps and wakes at regular intervals The foetus has defined fingers and toes and begins to grow hair, eyelashes and nails The foetus is 7 cm long and has all body parts are in place The foetus is fully developed and ready to be born, it is about 50 cm long and about 3.5kg
Answers Week 8 • The embryo is now called a foetus and has human features Week 10 • The foetus is 7 cm long and has all body parts are in place • The foetus has defined fingers and toes and begins to grow hair, eyelashes and nails Week 20 The foetus is 30cm long and the brain is very active. The foetus sleeps and wakes at regular intervals Week 30 • The foetus is fully developed and ready to be born, it is about 50 cm long and about 3.5kg Week 40
At about 9 weeks the foetus is about 25mm long is completely formed. The placenta and umbilical cord allow the exchange of carbon dioxide and oxygen and to get rid of waste. The ZYGOTE divides and three days later it becomes a ball of cells called an EMBRYO. The egg is released on the 14th day of a woman’s cycle. At 39 weeks the foetus is ready to be born and is fully developed. The embryo IMPLANTS into the uterus lining and a PLACENTA and UMBILICAL CORD start to develop. Millions of sperm are released into the vagina during intercourse. When the sperm fuses with the egg cell it is called FERTILISATION.
How does the foetus get oxygen? Any ideas?
How does the foetus get the substances it needs? Oxygen Water Vitamins Drugs (some) Viruses (almost all) Nutrients Foetus Mother Carbon dioxide Water Waste products ◆ substances cross placenta, then.... ◆ enter into the baby’s bloodthrough umbilical cord
Amniotic fluid acts as a ‘cushion’ TASK: Colour in the placenta and amniotic fluid in different colours. Copy and complete the statements below: _______________ - Supports and protects against shocks and physical damage. _______________ - Supplies nutrients and oxygen, from the mothers blood, to the foetus’ blood via the umbilical cord AND also removes carbon dioxide and other waste products. Amniotic Fluid Umbilical Cord
Label the diagram Placenta Amniotic fluid Foetus (baby) Umbilical cord Amniotic sac
Answers Foetus (baby) Placenta Umbilical cord Amniotic sac Amniotic fluid
When a woman is pregnant, extra parts develop in her womb to support the growing foetus • Draw a line between the parts and their function Amniotic sac Develops into the baby Umbilical cord Protects the unborn baby Foetus Attaches the unborn baby to the placents
Agony Aunt Dear Agony Aunt, I am pregnant and I am wondering How my baby gets all the nutrients and oxygen it needs. Also, If I smoke will it affect the baby? From Jenny Task: Write a response to Jenny to explain how her baby gets the oxygen and nutrients it needs and gets rid of the waste products. You should explain if they baby is affected by smoking.
True or false? When a zygote divides into a ball of cells it is called an embryo. Oxygen passes from the foetus to the mother. Nutrients pass to the foetus from the mothers blood. 4. Smoking will not harm a baby. Alcohol and some other drugs will harm a baby.
Reproduction order sequence Each person is given a card. Stand in the correct order, starting with ‘An egg cell is released from the ovaries...’