Fetus development

The fetus stays in the mother’s womb for about 9 months or 36-38 weeks and develops continuously.
1. First month: Fertilized ovum divides to form embryonal layer and primary organelles from embryonic layer. Then the embryonic coat, amara, umbilical cord, neural tube and body parts are formed. At this time the embryo is 0.25 cm long.
2. Second month: the skin of the head folds and ears are formed. Limbs and limbs are formed. Gill openings are seen in the tail and throat. By the end of the second month, the fetus is 2.6 cm long and weighs 0.95 g.
3. Third month: Fingers and toes develop. Reproductive organs are formed. By the end of the third month, the
4. Fourth month: Eyelids, eyebrows, nails and hair develop. Arms and legs move. Can suck thumb. By the end of the fourth month, the fetus is 13 cm long and weighs 141 (5 oz) grams.
5. Fifth month: Hair grows on the head. The skin is covered with lanugo (soft hair). By the end of the fifth month, the fetus is 25.4 cm long and weighs 0.5-1 lb.
6. Sixth month: The skin is red and wrinkled. Veins are visible on the skin. Fingerprints are visible. Eyelids begin to open. By the end of the sixth month, the baby is 30.48 cm long and weighs 2 pounds.
7. Seventh month: Fat accumulates in the body. The hearing organ is fully developed. Responds to sound, pain and light. At this time, the baby is 35.55 cm long and weighs 4 pounds.
8. Eighth month: Baby grows rapidly and can see and hear. All organs are developed except the lungs. At that time the child was 45.70 cm tall and weighed 5 pounds.
9. Ninth month: Lungs are fully developed. The baby’s eyes blink, head nods and fingers clench. Responds to light, sound and touch. At that time the child was 50.80 cm long and weighed 7 pounds.

Gastrulation of Embryogenesis

The process by which gastrula stage is formed from blastula is called gastrulation. In this process, the cells change rapidly and are arranged in two layers. The outer one is called ectoderm and the inner one is called endoderm. Later mesoderm is formed from ectoderm. A fluid-filled cavity forms inside the gastrula. It is called archenteron. The opening through which the archenteron is released is called the blastopore.

Cleavage of Embryogenesis

The process by which the zygote divides to form a multicellular embryo is called cleavage. As a result of division, the zygote becomes a sterile sphere with 16-32 cells. This is the marula stage and the cells are called blastomeres. The process of morula formation is called morulation. The cells of the marula dasa are arranged in a layer and a cavity filled with fluid is formed inside. This stage is called blastula. The cell layer of the blastula stage is called the blastoderm and the cavity is called the blastocoel. Cleavage process ends with the development of blastula stage.

Embryogenesis process, steps

Stages of embryogenesis are cleavage, gastrulation and organogenesis.
1. Cleavage: The process by which the zygote divides to form a multicellular embryo is called cleavage. As a result of division, the zygote becomes a sterile sphere with 16-32 cells. This is the marula stage and the cells are called blastomeres. The process of morula formation is called morulation. The cells of the marula dasa are arranged in a layer and a cavity filled with fluid is formed inside. This stage is called blastula. The cell layer of the blastula stage is called the blastoderm and the cavity is called the blastocoel. Cleavage process ends with the development of blastula stage.
2. Gastrulation: The process by which gastrula stage is formed from blastula is called gastrulation. In this process, the cells change rapidly and are arranged in two layers. The outer one is called ectoderm and the inner one is called endoderm. Later mesoderm is formed from ectoderm. A fluid-filled cavity forms inside the gastrula. It is called archenteron. The opening through which the archenteron is released is called the blastopore.
3. Organogenesis: The process by which various organs are formed from the embryonic stage is called organogenesis. A specific cell mass forms a specific organ. First, rudimentary buds are formed from the embryonic layer. Later, specific organs are formed from the organelles.

Mechanism of implantation

1. After fertilization the zygote divides by cleavage process to form blastomere. This condition is called Marula.
2. The morula enters the uterus and transforms to form a blastocyst. The outer layer of the blastocyst is called the trophoblast and the inner layer is called the blastocyst.
3. Within two days the blastocyst attaches to the endometrial epithelium of the uterus.
4. As the blastocyst attaches to the uterus, the trophoblast divides rapidly to form two layers. The inner layer is called cyto-trophoblast and the outer layer is called syncytio-trophoblast.
5. Syncytio-trophoblasts rapidly infiltrate the endometrial epithelium and endometrial stroma layers of the uterus.
6. Within seven days the endometrium of the uterus covers the blastocyst. As a result, the implantation is completed.
7. Trophoblasts divide rapidly to form numerous chorionic villi and amnion sheaths in the uterine endometrium.