What are the stages of embryo (fetus) development?

The fetus development

the fertilization occurs about two weeks after the first day of the last menstrual period when the sperm penetrates the egg, and within 24 hours after the fertilization, the egg begins dividing rapidly into many cells.

The fertilized egg remains in the fallopian tube for about three days, the fertilized egg (called a blastocyte) continues to divide, and it passes through the fallopian tube to the uterus to be implanted in its lining (a process called the implantation).

From embryo and fetus

From embryo to fetus

The developing baby is called an embryo from the moment of conception to the eighth week of pregnancy, and after the eighth week and until the moment of birth, the developing baby is called a fetus.

What are the stages of embryo (fetus) development?
The stages of fetal development

The stages of fetal development

The period of pregnancy (9 months) can be divided into 4 main stages which are:

The first stage:
Fetal brain development

The fetal brain development

The first stage starts from the moment of zygote formation till the end of the sixth week, In this stage, the head starts to differentiate (it is similar to the reptiles head), The eyes appear distinctly, In the sixth week, the heart can be seen and heard pulsating using the sonar.

The second stage :

The second stage starts from the beginning of the seventh week till the end of the twelfth week, In this stage, the facial features can be distinguished, the genital organs start to develop and the appearance of the digits in the limbs.

Normal fetal growth

The normal fetal growth

The third stage:

The third stage starts from the beginning of the 13th week till the end of the 22th week, In this stage, the bones start to develop, as well as the circulatory system, the sex of the embryo can be distinguished, and the mother can feel the movement of her fetus due to the strength of the embryo muscles which help in the movement.

The fourth stage:
The fetus at the eighth month .

The fetus at the eighth month

The fourth stage starts from the beginning of the 23th week till the delivery (the birth), In this stage, the development of all body systems is completed, the embryo can move his hands and feet.

Before the delivery, the embryo position changes gradually to be inverted, where the head is directed towards the cervix, The baby can be born in the 28th week, where his two lungs are able to respire and all systems are completely developed.

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Structure of Female genital system & ovum, Oogenesis stages & Menstrual cycle

Fertilization process, Pregnancy and the stages of embryonic development

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2 Responses

  1. abbas mobarak says:

    so we can say that bones developes first then muscles,correct me if i m wrong please

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