Human embryos

General Information
Latin	embryo
Greek
TA98
TA2
FMA
Details
System	Reproductive system
Artery
Vein
Nerve
Lymphatic drainage
Precursor	Fertilization
Function
Identifiers
Clinical significance
Notes

A human embryo is the early stage of human development that occurs from fertilization until the end of the eighth week (56 days) of gestation. The development of the human embryo is a complex process that involves rapid cell division and differentiation.

Development Stages

Fertilization

Fertilization is the process by which a sperm cell from a male and an ovum (egg) from a female combine to form a zygote. This marks the beginning of the embryonic stage of development.

Cleavage

After fertilization, the zygote undergoes a series of rapid cell divisions known as cleavage. These divisions result in a multicellular structure called a morula.

Blastocyst Formation

The morula develops into a blastocyst, which is characterized by a fluid-filled cavity and differentiated cell types. The blastocyst implants into the uterine wall around the sixth day after fertilization.

Gastrulation

During gastrulation, the blastocyst reorganizes into a three-layered structure known as the gastrula. These layers are the ectoderm, mesoderm, and endoderm, which will give rise to all the tissues and organs of the body.

Organogenesis

Following gastrulation, the process of organogenesis begins, where the embryonic germ layers develop into the major organs and systems of the body.

Embryonic Structures

Amniotic Sac

The amniotic sac is a fluid-filled membrane that surrounds and protects the embryo throughout development.

Placenta

The placenta is an organ that forms during pregnancy, providing oxygen and nutrients to the growing embryo and removing waste products.

Umbilical Cord

The umbilical cord connects the embryo to the placenta, facilitating the exchange of nutrients and waste.

Clinical Significance

Embryo Research

Research on human embryos is crucial for understanding congenital disorders and developing reproductive technologies. Ethical considerations are paramount in this field.

Assisted Reproductive Technology

Techniques such as in vitro fertilization (IVF) involve the manipulation of embryos outside the human body to assist with infertility treatment.

See Also

• Fetal development
• Embryology
• Human reproduction

External Links

• Embryology.ch
• National Institute of Child Health and Human Development