pregnancy & fetal development


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PREGNANCY & FETAL DEVELOPMENT. Sperm are made in the testes. Tail helps the sperm to swim so it can find the egg. Very little cytoplasm so it can swim fast. Special chemicals at the tip help the sperm to get into the egg. Eggs are made in the ovaries. - PowerPoint PPT Presentation




Sperm are made in the testes.Tail helps the sperm to swim so it can find the eggSpecial chemicals at the tip help the sperm to get into the eggVery little cytoplasm so it can swim fastEggs are made in the ovaries.

Jelly coat means that only one sperm can get into the egg.Lots of cytoplasm so there is lots of food for the new baby.

It only takes one sperm to get into the egg to make a baby.When a sperm joins with an egg, this is how a new baby starts.Stages of Reproduction

Fertilization~Joining of an egg and a sperm in the fallopian tube***VIDEO*** Click on pictureHow Pregnancy Happens5Pregnancy 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.

Embryo:A fertilized egg in the first 2 months of pregnancyFetus:From the 3rd month on the embryo is called a fetus.

BABY DEVELOPMENTNote: The second trimester is until about week 278

(Adapted from Introduction to Biology, D.G.Makean; published by John Murray 1971)(a)Eggs are produced in organ X. What is the name of organ X?(b) The baby grows in a bag of amniotic fluid which is inside organ Y. What is the name of organ Y?(c)Through which part, labeled in the diagram, is food passed from the mother to the baby?(d) Name one useful substance, other than food, which passes from the mother to the unborn baby.(e)The diagram shows an organ system of the mothers body. What is the name of this organ system?The PlacentaOrgan attached to the inside of the uterus and connected to the fetus by the umbilical cord.Produces pregnancy-related hormonesTrading-post between mother and baby (the baby gets oxygen and nutrients from the mother this way)Mother/babys blood never mixesPancake-shaped organ

The Umbilical CordA cord that attaches placenta to the fetusCan be 60 cm longCarries oxygen and nutrients from placenta to fetus, carries fetuss blood back to placentaWhen this is cut, it forms your belly button!

The Amniotic SacSac containing the fetusThin but tough pair of transparent membranesFilled with amniotic fluid (at maximum, it contains 1 L of fluid)

Amniotic FluidA protective liquid in the amniotic sac, surrounds fetusCushions fetus against blows to mothers abdomenInhaled and exhaled by fetusPromotes fetal developmentKeeps a constant temperature


30 hours after fertilization

WEEK 3-5 The babys tiny heart begins to beat by day 21. The arms, legs eyes, lips and nose begin to grow.

WEEK 7 The organs start to grow inside the baby. The baby starts to move.

WEEK 8-12 The baby has hands and feet, and swims and moves inside the bag of water.FIRST TRIMESTERStart of the 8th week Developing human is called a fetusBrain waves can be detectedMuscle movements beginBones and muscles are developingAll major body parts have formed

4th WeekHeart starts beatingArm and leg buds appearEyes and brain begin to develop Embryo is less than of an inch longUmbilical Cord Connects the embryo to the placenta

First 3 Months

Weeks 13-20

The baby can swallow, and starts to try breathing. It can feel pain, and moves around a lot. It has eyebrows and eyelashes now.

Week 20-24

The baby has hand and footprints. It practices breathing.

Weeks 25 32

The babys eyes open and close, and it sleeps 90% of the time.

SECOND TRIMESTEROrgan systems continue to develop

By 4 months mother can feel the fetus move or kick

Reproductive organs can be recognized as distinctly male or female

Fetus can hear and recognize voices

Hair forms on the head

Months 4-6

Weeks 33 40

The baby is getting ready to be born. It turns upside down before it is born.THIRD TRIMESTER

Months 7-9Time when the fetus gains most of its weight

Most fetuses are about 20 inches

Brain develops further

All other organs are almost complete

Fetus can grasp with his/her hands

Fetuss skin becomes smooth fat deposits underneath the skin

Nervous system will continue to develop after birth

Newborn baby

Stages of Birth:Labor mild contractions pushes the baby against the cervix

2. Birth Baby pushes through the cervix and into the birth canal.

3. After birth After the baby is delivered, the placenta separates and is delivered.


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