UNIT+7-+EMBRYOLOGY



=Objective= Successfully understand the stages of an embryo and how it is made. = = =Introduction= Embryology is the study of the development of an embryo. An embryo is defined as any organism in a stage before birth or hatching, or in plants, before germination occurs.Embryology refers to the development of the fertilized egg cell and its differentiation into tissues and organs. Embryology was originally a more descriptive science until the 20th century. Embryology today deals with the various steps necessary for the correct and complete formation of the body of a living organism.

=Glossary= Amnion: membranous sac that surrounds and protects the embryo.

Blastula: a hollow ball of cells organized into an epithelial monolayer.

Chorion: one of the membranes that exists during pregnancy between the developing fetus and mother. It surrounds the embryo and other membranes.

Ectoderm: The ectoderm is the start of a tissue that covers the body surfaces. It emerges first and forms skin and nerver.

Endoderm: the endoderm is one of the germ layers formed that developes into glands, the liver, and the pancreas.

Embryo: Stage of developement from the first division of the zygote until body structures begin to appear.

Fertilization: fertilization is when sperm is deposited in or close to the female reproductive tract, and gametes unite with the tract.

Gastrula: ball with germ layers.

Implantation: the event that occurs early in pregnancy in which the embryo inbeads to the wall of uterus.

Morula: is an embryo at an early stage of embryonic development, consisting of 12-32 cells.

Sperm: a relatively small cell produced my the male, that enters the female in reproduction that moves my means of a flagellum.

Zygote: is a cell that is the result of fertilization.