BY:NURUL HIDAYAH BT MANSOR

HILDA ANAK EMAKAMIRAH BT SHAARI

AIN NAJWA BT AMRAN

Chapter 3 : development

of zygote

STEP 1 : GROUP SETTING

Our group consist of 5 members chosen by ourself

This is our group’s member

Ain Najwa Bt AmranHilda anak Emak Lee Yian Ping

Amirah Bt ShaariNurul Hidayah Bt Mansor

HOW TWINS ARE FORM?

Twins are two offspring resulting from the same pregnancy. The twins can be the same or different sex which mean they can either be monozygotic (identical) or dizygotic or (non-identical).

TYPES OF TWIN

•Monozygotic twins•Dizygotic twins

•Half twin•Conjoined twins

MONOZYGOTIC TWINSCome from one zygote

Identical twins

DIZYGOTIC TWINS

• Come from two zygotes• Non-identical @ fraternal

twins

HALF TWINSemi-identical twin

Have the same genes from the mother but different genes from

the father

CONJOINED TWIN

• Many complication resulting of shared organ

• Occur when the division later than 8 days

DEVELOPMENT OF IDENTICAL TWIN!!

Firstly is the union of 1 sperm 1 ovum. After the sperm fertilized the ovum, cell

division occur. Then, it undergoes cleavage.

The cell is divided into 2 cell. Each of the 2 cell then continued divided respectively into morula.

The morula enter the uterus and develops a central cavity. This structure known as blastocyst. The blastocyst attached to the uterine wall to begin the process of implantation.

Once the cleavage is complete, gastrulation stage is started.

The primary germ layers are organized into 3 layers :~ The external layer is called

ectoderm~ The middle layer is called

mesoderm~ The most internal layer is called

endodermThe gastrulation followed by

organogenesis.

Monozygotic twins develop in 3 ways :

1 placenta and 2 amniotic sac ( mono-chorial and bi-amniotic)Only 1 placenta and 1 amniotic sacs

( mono-chorial and mono-amniotic) 2 placenta and 2 amniotic sacs (bi-chorial and bi-amniotic)

1 PLACENTA AND 2 AMNIOTIC SACS

(MONO-CHORIAL AND BI-AMNIOTIC)

The inner cell mass of blastocyte split completely before the blastocyte has fully defined the roles of each type of cells.

Because there are 2 inner cell mass, hence there are 2 amniotic cell in 1 placenta.

ONLY 1 PLACENTA AND 1 AMNIOTIC SACS

( MONO-CHORIAL AND MONO-AMNIOTIC)

After implantation, the inner cell mass splitted into epiblast and hypoblast. The fluid-filled space created by the separation becomes the amniotic cavity.

The epiblast develop into amniotic sacs while the hypoblast divide into 2 embryo.

2 PLACENTA AND 2 AMNIOTIC SACS

( BI-CHORIAL AND BI-AMNIOTIC)

The blastocyte splitting at 2-cell stage form :

The inner cell mass will develop into embryo itself.

the outer single layer of cells then form tropoblast. Then tropoblast develop into placenta.

Because there are 2 blastocyte, they will be 2 placenta and 2 separate amniotic sacs.

DEVELOPMENT OF NON-IDENTICAL TWINS

Fertilization of 2 different oocyte by 2 different sperms.

2 separate pregnancy occur at the same time forming 2 different amniotic sacs and 2 different placenta.

So, the embryo is non-identical.

Aspect Identical twins Non-identical twins

fertilization One sperm and one ovum

Two separate eggs and two separate spermatozoa

Formation of zygote Eggs divide into two embryo

Each egg divide into one embryo respectively

Genetic constitution (chromosomes)

Exactly the same Different

Number of placenta One or two two

Number of amniotic sacs

One or two two

sex Same sex Can be same or different sex

Physical appearance Look alike Doesn’t look alike

WHAT IS THE DIFFERENCE BETWEEN IDENTICAL AND NON-

IDENTICAL TWINS

WHAT IS THE COMPLICATION OF TWINS?

The complication of having multiple are low birth weight of the baby because twin usually born premature.

Twin to twin transfusion syndrome which mean the blood from one twin is being diverted into the other twin.

Miscarried twin usually occur when a mother suffering in their early pregnancy yet the pregnancy still continued.

WHAT IS THE MOTHER RISK HAVING MULTIPLE PREGNANCY?

Mother with gestational diabetes during their pregnancy with twins or more, probably because the increase in hormones produced by carrying an additional baby (or babies) interferes with their body's ability to process insulin.

Placenta problem occur whether there is a single, shared or multiple placentas, mothers of twins or more are at greater risk for complications. Problems affecting the placenta can result in dangerous complications for the mother, including hemorrhage during pregnancy or after delivery.

Heart problem usually happen to mother with multiple pregnancy because of each additional fetus raises the level of cardiac output.

Ultrasound scan The fastest way to know that you are having twins By producing ultrasound image which shows

whether its more than one fetus.

Elevated HcG Levels HcG (human chorionic gonadotropin) is a hormone

detectable in pregnant women's blood or urine about 10 days post-conception.

Twins may produce an elevated level of HcG.

HOW DO WE KNOW WE ARE HAVING TWINS?

Doppler heartbeat count By using Doppler system that amplifier fetal heart

sounds And experienced physician or midwife can hear two

heat beats The sounds can be misleading The second heartbeat may be background noise or

mother’s own heartbeat.

Weight Gain Mothers of twins usually gain about 10 lbs. more than

singleton mothers.

Excessive Morning Sickness Mother of twins experience double dose of morning

sickness Experience vary greatly depends on individual

Early/Frequent Fetal Movement many mothers of multiples experience more frequent

or earlier fetal movement considerable disagreement among medical

professionals on the subject Because some women will recognize feeling of early

movement even if just carrying one baby

Extreme Fatigue the body is working overtime to nurture more than

one baby

History/Hunches A family history of multiples, or a powerful hunch can

be convincing indicators that they are having twins.

HOW TO DELIVERED TWINS??

Usually, twins get birth smoothly, with both born head down. However, caesarean sections are more common with twins.

One or both might be breech, coming bottom or feet first. Which mean one baby lies across the uterus, in a case like this, caesarean is essential. Twins can also be smaller and weaker than single babies and a caesarean might be the easiest, least stressful way for them to be born.

Twins are more likely to need some time in special care after the birth. You'll probably be advised to stay a little longer in hospital yourself, even if your twins are perfectly healthy (as most are).

HOW TO BREASTFEEDING

TWINS? A mother’s breast can make as much

milk as the babies need - twice the stimulation of the supply, means twice the amount made.

It's the practical aspects that might be more tricky - how to hold them so you're all comfortable, whether to feed them one at a time or together and so on. The babies may not have the same appetite and they may be hungry at different times too.

THAT’S ALLTHANK YOU