Embryo
Embryo is the early developmental stage of a multicellular organism formed after fertilization. In humans and many animals, the embryo develops from a fertilized egg called a zygote and undergoes cell division, growth, and differentiation to form tissues and organs. :contentReference[oaicite:0]{index=0}
Embryonic development is studied in the field of Embryology and is an important process in biology, medicine, and developmental science.
Overview
Embryonic development begins after fertilization when male and female gametes fuse to form a zygote.
The developmental process can be represented as:
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The embryo undergoes rapid cell division and structural development during the early stages of life. :contentReference[oaicite:2]{index=2}
Stages of Embryonic Development
Fertilization
Fusion of sperm and egg forms a zygote. :contentReference[oaicite:3]{index=3}
Cleavage
The zygote undergoes repeated cell division without significant growth.
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Blastulation
Formation of the blastula or blastocyst stage occurs.
Gastrulation
Three germ layers are formed:
- Ectoderm
- Mesoderm
- Endoderm
Organogenesis
Development of tissues and organs begins. :contentReference[oaicite:5]{index=5}
Human Embryo
In humans, the embryonic stage generally lasts until the end of the eighth week after fertilization, after which the developing organism is called a fetus. :contentReference[oaicite:6]{index=6}
During this period:
- Major organs begin to form
- The nervous system develops
- The heart starts beating
- Limb structures appear
Importance
Embryos are important in:
- Developmental biology
- Medicine
- Genetics
- Stem cell research
- Reproductive science
The study of embryos helps scientists understand growth, congenital disorders, and tissue formation.
Embryology
The scientific study of embryos and embryonic development is known as Embryology. It examines how organisms develop from a single fertilized cell into complex multicellular organisms. :contentReference[oaicite:7]{index=7}