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Human embryonic development or human embryogenesis is the development and formation of the human embryo. It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of development.
This page shows some key events of human development during the embryonic period of the first eight weeks (weeks 1 - 8) following fertilization. This period is also considered the organogenic period, when most organs within the embryo have begun to form.
Overview. What are the three stages of fetal development called? Fetal development is an orderly and intricate process. It begins before you even know you’re pregnant and ends with the birth of your baby. Between conception and delivery, there are many detailed steps that have to occur.
A developing human is referred to as an embryo during weeks 3–8, and a fetus from the ninth week of gestation until birth. In this section, we’ll cover the pre-embryonic and embryonic stages of development, which are characterized by cell division, migration, and differentiation.
Jul 6, 2017 · An embryo refers to the early developmental stage of eukaryotic organisms following the fertilization of an egg (derived from a female) by sperm (derived from a male) as a method of sexual reproduction.
In this section, we’ll cover the pre-embryonic and embryonic stages of development, which are characterized by cell division, migration, and differentiation. By the end of the embryonic period, all of the organ systems are structured in rudimentary form, although the organs themselves are either nonfunctional or only semi-functional.
An embryo is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell.
Development in Xenopus and Drosophila passes through three rather different (although often overlapping) phases: Establishing the main axes (anterior-posterior; dorsal-ventral; left-right). This is done by gradients of mRNAs and proteins encoded by the mother's genes and placed in the egg by her.
During the second week after fertilization, cells in the embryo migrate to form three distinct cell layers, called the ectoderm, mesoderm, and endoderm. Each layer will soon develop into different types of cells and tissues, as shown in Figure below. Cell Layers of the Embryo.
May 9, 2024 · embryo, the early developmental stage of an animal while it is in the egg or within the uterus of the mother. In humans the term is applied to the unborn child until the end of the seventh week following conception; from the eighth week the unborn child is called a fetus.
