Twins

PRESENTED BY: =SAYIDAH NAFISAH =SITI SARAH SAZLIANA =NOR HASMALINA =NUR HASNI =AYUNI AMALINA

Question… A group of 5 students of Medical Institute, University of Malaya are assigned to teach the matriculation students about human development. They were asked to identify and describe the twin formation during the fertilization process. As a very excellent students, how they prepare their lesson. Suggest and explain what the students will do to complete their lesson.

FACT

IDEA

LEARNING ISSUES

ACTION

2.Give

information to matriculation student about human development.

•The

objective is to inform them about how human develop. •Sometimes, multiple pregnancies can occur instead the normal pregnancy. •There are three types of multiple pregnancies.

•Is

•Surfing

2.We try to identify the twin formation.

•Twin

•What

formation divided into monozygotic, dizygotic and siames. •Monozygotic can be divided into three type of cell division.

the human develop by the same way? •What process which cause the multiple pregnancy? •What are the type of multiple pregnancies?

internet. •Go to the library.

is mean by •Surfing monozygotic? internet. •What is mean by •Go to the dizygotic? library. •What is mean by siames? •What the type of cell division in monozygotic twin?

3. We describe the twin formation during fertilization process.

•Each

formation has their own process.

4. We identify the characteristic of each of them.

•The

•How

monozygotic twin occur? •How dizygotic twin occur? •How siames twin form?

characteristics •What is the characteristic of each twin are not of monozygotic twin? •What is the characteristic same. of dizygotic twin? •What is the characteristic of siames twin? •What is different characteristics between these three type of twins?

•Surfing

internet. •Go to the library.

•Surfing

internet. •Go to the library.

TWINS…. Twins are two offspring from the same pregnancy, usually born in close succesion.

Type of twins

identical@ monozygotic

fraternal@ non-identical @ dizygotic

Siamese twin

Cause the multiple pregnancy occur!!!!!! >>>Multiple pregnancies happen when one fertilized zygote divided into two developing embryo. >>>It also occur when two eggs are fertilized by two different sperm. >>>This twins zygote that formed will develop into different individuals.

MONOZYGOTIC TWIN 

The monozygotic mean that the type of twins derived from a single (mono) egg (zygote). Monozygotic twins form when a single fertilized egg splits into two embryos. Because the twins share the same DNA set, they tend to have similar features.

Identical @ monozygotic twins…. 

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Involve only one ovum and one sperm. After fertilization, the embryos will divide into two part and develops into two separate individuals. Have same chromosome, same resemblance and same sex. Genetically and physically similar.

3 ways how identical twins can develop???

>>>>Monochorial and mono-amniotic  Mean that it only have one placenta and one amniotic sacs.  Separation take place after amniotic bag already formed. >>>>Monochorial( placenta) and biamniotic  Separation take place little later in the development but before the blastocyte has fully defined the role of each type of cell.  Have only one placenta and two amniotic sacs >>>>Bichorial and bi-amniotic  Have two placenta and two amniotic sacs.

How identical twins can be formed???????? .

CHARACTERISTICS THE MONOZYGOTIC TWIN 

The characteristics of monozygotic twin is the twins are of the same sex and physically similar because they both come from one ovum, which, after fertilization, divides in two and develops into two separate individuals.

IDENTICAL TWIN

DIZYGOTIC TWIN 

The dyzygotic mean that the twins who have shared a common uterine environment with its twin but is due to a different fertilized ovum. Dizygotic twins are also called fraternal twins

Non- identical @ fraternal @ dizygotic twins 

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Two eggs fertilized by two sperm or it occur when two fertilized eggs are implanted in the uterine wall at the same time. Have different chromosome, don’t look alike, can be same or different sex. Dizygotic twins may look similar, particularly given that they are the same of age. Not genetically alike. Involve bi-chorial and bi- amniotic cellular division. It mean that the twin zygote will have their own placenta ( chorion) and amniotic sacs.

CHARACTERISTICS OF THE DIZYGOTIC TWIN 

Among dizygotic twins, each one has separate amnion and separate chorion membranes. Fraternal twins, who are no more genetically alike than ordinary siblings, maybe of the same or different sex and may bear some similarity of appereance.

Fraternal twins

Fraternal twins

SIAMESE TWIN

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Births of conjoined twins, whose skin and internal organs are fused together

Siamese twins

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Also known as conjoined twins. Formed when identical twins do not separate completely and still partially united and the zygote starts to split after day 13 following fertilization. It also due to the incomplete division of one fertilized ovum. The twins may joined at several part of body. May share several organ such as brain, heart or liver. Usually the majority who survive are joined ventrally. Most conjoined twins are now evaluated for surgery to attempt to separate them into

CHARACTERISTICS THE SIAMES TWIN 

The characteristic of the Siamese twin is births of conjoined twins, whose skin and internal organs are fused together.

Siamese twins share heart

 

                                                                                

Twin pregnancy types

Scenario 3: Identical twins

Monozygotic twin pregnancy Mono-chorial & mono-amniotic.

Scenario 4: Fraternal twins

Dyzygotic twin pregnancy Bi-chorial and bi-amniotic.

Comparison between identical twins with fraternal twins >>>fertilization >>>formation of zygote >>>genetic constitution >>>number of placenta >>>sex >>>physical characteristics