Embryonic Development and Gestation

These flashcards cover key vocabulary and concepts related to embryonic development and gestation.

Zygote

The fertilized egg formed from the fusion of sperm and egg.

Embryo

The developing organism from week 3 to week 8 after fertilization.

Fetus

The developing organism from week 9 until birth.

Gestation

The period of development of the embryo and fetus during pregnancy.

Morula

A solid ball of cells resulting from cleavage of the zygote, typically 16 cells in size.

Blastocyst

A hollow structure formed from the morula, consisting of an inner cell mass and an outer trophoblast.

Trophoblast

The outer layer of the blastocyst that contributes to the placenta.

Human Chorionic Gonadotropin (hCG)

A hormone secreted by the syncytiotrophoblast that signals the corpus luteum to maintain progesterone production.

Cleavage

The series of mitotic divisions that occur after the formation of a zygote.

Ectopic Pregnancy

A pregnancy that occurs outside the uterus, often in the uterine tubes, which is typically not viable.

Neural Tube

A structure formed from the neural plate that develops into the brain and spinal cord.

Gastrulation

The process during development where the three germ layers (ectoderm, mesoderm, endoderm) are formed.

Amniotic Fluid

The fluid that fills the amniotic sac and protects the developing embryo or fetus.

Placenta

An organ that develops in the uterus, providing nutrients and oxygen to the fetus and removing waste.

Umbilical Cord

The structure connecting the fetus to the placenta, containing blood vessels that transport nutrients and waste.

Hox Genes

A group of genes that determine the body plan and the positioning of structures during embryonic development.

Meconium

A thick, dark green substance forming the first feces of a newborn, consisting of material ingested during fetal life.

Lactation

The production of breast milk following childbirth, stimulated by hormones.

Colostrum

The first milk produced during lactation, rich in antibodies and nutrients.