The process of prenatal development occurs in three main stages. The first two weeks after conception are known as the germinal stage, the third through the eighth week is known as the embryonic period, and the time from the ninth week until birth is known as the fetal period.
What are the 4 stages of embryonic development?
- Germinal stage. 1.1 Fertilization. 1.2 Cleavage. 1.3 Blastulation. 1.4 Implantation. 1.5 Embryonic disc.
- Development of organs and organ systems.
What are the stages of embryology?
- Fertilization. Fertilization is the union of the female gamete (egg) and the male gamete (spermatozoa). …
- Blastocyst Development. …
- Blastocyst Implantation. …
- Embryo Development. …
- Fetal Development.
What are the types of embryonic development?
There are two main types of cellular development that pertain to embryos: mosaic development or regulative development.
What is the early stage of embryonic development?
The early stages of embryonic development begin with fertilization. The process of fertilization is tightly controlled to ensure that only one sperm fuses with one egg. After fertilization, the zygote undergoes cleavage to form the blastula.
What are the 6 stages of embryonic development?
- F. Fertilization- 12-24 hours after implantation.
- C. Cleavage- a series of mitotic cell division convert zygote into multicellular embryo.
- M. Morula- cells become a solid ball.
- B. Blastula- fluid filled cluster of cells, inner cell mast develops.
- G. Gastruela- 3 primary germ layers form.
What part of the body grows first in the womb?
Arms and legs.At first, your baby’s arms and legs begin as little buds that sprout from the embryo’s sides. As they grow, the arms look like paddles and the legs look like flippers. A ridge appears on the end of each one. They eventually become your baby’s fingers and toes.
What are the two main stages of embryonic development?
The cleavage and blastula stage The initial growth stages of multi-cellular organisms start with a zygote cell, which then undergoes fast cell division to form the initial cell cluster, or ‘blastula’.
How does a human embryo develop?
During fertilization, the sperm and egg unite in one of the fallopian tubes to form a zygote. Then the zygote travels down the fallopian tube, where it becomes a morula. Once it reaches the uterus, the morula becomes a blastocyst. The blastocyst then burrows into the uterine lining — a process called implantation.
What are the main features of embryonic development?
Embryonic Development After the 1st month of pregnancy, the heart develops. Limbs and digits develop in the 2nd month. By the end of 1st-trimester or 3rd month all the major organ systems develop. Genital organs are visible.
What is meant by embryonic?
1 : of or relating to an embryo. 2 : being in an early stage of development : incipient, rudimentary an embryonic plan.
What are the stages in animal embryonic development?
Gastrulation: the dramatic rearrangement (movement) of cells in the blastula to create the embryonic tissue layers. These tissue layers will go on to produce the tissues and organs of the adult animal. Organogenesis: the process of organ and tissue formation via cell division and differentiation.
What is the importance of embryonic development?
The process in which an organism develops from a single-celled zygote to a multi-cellular organism is complex and well-regulated. The early stages of embryonic development are also crucial for ensuring the fitness of the organism.
Which is the last stage in pre-embryonic development?
Implantation. At the end of the first week, the blastocyst comes in contact with the uterine wall and adheres to it, embedding itself in the uterine lining via the trophoblast cells. Thus begins the process of implantation, which signals the end of the pre-embryonic stage of development (Figure 28.2.
What is the last organ to form in a fetus?
Almost all organs are completely formed by about 10 weeks after fertilization (which equals 12 weeks of pregnancy). The exceptions are the brain and spinal cord, which continue to form and develop throughout pregnancy. Most malformations (birth defects) occur during the period when organs are forming.
How big is a 2 week old fetus?
Your baby is right around 4 inches long from the top of the head to the rump and weighs about 4 1/2 ounces — roughly the size of a small peach.