Fertilization and Early Development

Fertilization is the process by which a sperm cell and an egg cell unite to form a zygote, which is the first cell of a new organism.

Fertilization typically occurs in the fallopian tube, which is a thin tube that connects the ovary to the uterus.

The amnion is a thin, transparent membrane that forms around the developing embryo and fills with amniotic fluid, which provides a protective environment for the embryo.

The placenta is a specialized organ that forms during pregnancy and serves multiple functions, including providing oxygen and nutrients to the embryo, removing waste products from the embryo, and producing hormones that support pregnancy.

Cleavage is the stage of development that begins with the formation of the zygote and ends with the implantation of the embryo in the uterus. During cleavage, the zygote divides repeatedly to form a ball of cells called a blastocyst.

Gastrulation is the stage of development that begins with the implantation of the embryo in the uterus and ends with the formation of the major organs. During gastrulation, the three germ layers (ectoderm, mesoderm, and endoderm) are formed.

Organogenesis is the stage of development that begins with the formation of the major organs and ends with the birth of the organism. During organogenesis, the various organs and tissues of the organism are formed.

The postnatal period is the period of development that begins with the birth of the organism and ends with the attainment of adulthood. During the postnatal period, the organism grows and develops, and its various organs and tissues mature.

Implantation is the process by which the fertilized egg implants in the lining of the uterus.

Progesterone is the hormone that is produced by the corpus luteum and helps to maintain the pregnancy.

The umbilical cord is the structure that connects the placenta to the fetus.

Parturition is the process by which the fetus is expelled from the uterus.

Gestation is the stage of development that begins with the formation of the zygote and ends with the birth of the organism.

Childhood is the period of development that begins with the birth of the organism and ends with the attainment of adulthood.

Delivery is the process by which the embryo is expelled from the uterus.