Embryonic

Embryonic refers to the stage in a life cycle that begins at fertilization and lasts until birth. This term is often used in biology and medicine to describe the early development of an organism, particularly in the context of human development.

Overview

The embryonic stage is a critical period in the life cycle of an organism. It is during this time that the zygote, a single cell formed through the fusion of an egg and sperm, begins to divide and differentiate into the various cell types that will eventually form the adult organism. This process is known as embryogenesis.

Stages of Embryonic Development

Embryonic development can be divided into several stages:

1. Cleavage: This is the first stage of embryonic development, during which the zygote divides into multiple cells.
2. Blastulation: During this stage, the cells of the embryo arrange themselves into a hollow sphere known as a blastocyst.
3. Gastrulation: This stage involves the formation of the three primary germ layers: the ectoderm, mesoderm, and endoderm.
4. Organogenesis: This is the stage during which the germ layers differentiate into the various organs and tissues of the body.

Embryonic Development in Humans

In humans, the embryonic stage begins at fertilization and lasts until the end of the eighth week of gestation. During this time, the embryo undergoes rapid growth and development. By the end of the embryonic stage, all of the major structures and organ systems of the body have begun to form.

See Also

• Fetus
• Pregnancy
• Developmental biology
• Embryology