Endoderm is one of the germ layers-- aggregates of cells that organize early during embryonic life and from which all organs and tissues develop. All animals, with the exception of sponges, form either two or three germ ...

Ectoderm is one of three germ layers--groups of cells that coalesce early during the embryonic life of all animals except maybe sponges, and from which organs and tissues form. As an embryo develops, a single fertilized ...

Congenital rubella syndrome (CRS) can occur in children whose mothers contracted the rubella virus, sometimes called German measles, during pregnancy. Depending on the gestational period when the mother contracts rubella, ...

The French flag model represents how embryonic cells receive and respond to genetic information and subsequently differentiate into patterns. Created by Lewis Wolpert in the late 1960s, the model uses the French tricolor ...

Although the concept of quickening was not developed initially by the Roman Catholic Church, much of their histories are intertwined. Quickening, the point at which a pregnant woman can first feel the movements of the ...

John Hilton Edwards first described the symptoms of the genetic disorder known as Trisomy 18 - one of the most common forms of trisomy, which occurs when cells have an extra copy of a chromosome, in humans - in 1960. Trisomy ...

Amniocentesis is a test used for prenatal diagnosis of inherited diseases, Rh incompatibility, neural tube defects, and lung maturity. Normally performed during the second trimester of a pregnancy, this invasive procedure ...

The process of gastrulation allows for the formation of the germ layers in metazoan embryos, and is generally achieved through a series of complex and coordinated cellular movements. The process of gastrulation can be ...

Embryonic differentiation is the process of development during which embryonic cells specialize and diverse tissue structures arise. Animals are made up of many different cell types, each with specific functions in the ...

When placental mammals are born their circulatory systems undergo radical changes as the newborns are prepared for independent life. The lungs are engaged, becoming the primary source of fresh oxygen, replacing the placental ...