Endoderm Yolk

Vitelline endoderm (lat. Entoderma extraembryonica, also known as hypoblast, or extraembryonic ectoderm, lat. Hypoblastus extraembryonicus) is a layer of cells in the embryos of vertebrates and humans that develop from the endoderm of the yolk sac and form the walls of the yolk sac.

The vitelline endoderm is one of the important layers in the embryo, as it participates in the formation of many organs and systems of the body. For example, the vitelline endoderm forms the walls of the yolk sac, which is the first organ of the digestive system in the embryo. It is also involved in the formation of the liver, lungs, heart, kidneys, bladder and other organs.

The cells of the vitelline endoderm are cubic in shape and contain many mitochondria and the endoplasmic reticulum. They also contain special proteins, such as glycoproteins, that help them attach to other cells and tissues.

The development of the yolk endoderm occurs during the first few days after fertilization. It is formed from endoderm cells of the yolk sac through division and migration. During this process, the yolk endoderm cells become more differentiated and form the walls of the yolk sac. After this, the yolk endoderm continues to develop, forming other organs and tissues.

However, in some embryos, especially mammals, the yolk endoderm may be damaged or absent as a result of genetic disorders or adverse environmental factors. This can lead to various diseases and developmental defects, including Down syndrome and other chromosomal abnormalities.

Endoderm is the inner layer of the wall of the embryonic membranes or trophoblast in higher animals (for example, humans, mice, etc.).

The endoderm comes from the germinal membrane (ablastica), with which it is fused after splitting the wall. After this, it differentiates into the chorionic layer or placenta. In embryogenesis, during the development of the amniotic membrane, located on the surface of the chorion, the endodermis secretes fluid that accumulates around the fetus (amniotic cavity).

During pregnancy, the chorionic villi interact with the amniotic layer, which covers the surface of the embryo. In this case, the villi penetrate the epithelium and penetrate the interstitium. Once connected, these cells become part of the endometrium. Sometimes this can lead to conflicts when there are too many villi, which causes a pathological pregnancy. The production of female hormones in the corpus luteum makes the cytoplasm non-homologous, which makes it impossible to determine the original tissue.