Fetal Growth and Development Vocabulary

Vocabulary flashcards covering the stages of fertilization, embryonic development, placental function, and post-natal recovery based on the lecture notes.

Spermatozoa

The male reproductive cells (sperm) of which hundreds of millions are ejaculated, but only thousands reach the fallopian tubes.

Corona Radiata

The outer layer of granulosa (follicular) cells surrounding the secondary oocyte during ovulation.

Zona Pellucida

A transparent, thick glycoprotein layer surrounding the oocyte that contains receptors for sperm binding.

Acrosomal Reaction

The release of enzymes from the sperm's acrosome to help it burrow through the corona radiata and zona pellucida.

Capacitation

The process occurring in the female reproductive tract where sperm become fully functional and capable of fertilization.

Polyspermy

The penetration of an oocyte by more than one sperm, which is prevented by oocyte membrane depolarization and calcium ion influx.

Zygote

A fertilized oocyte formed by the fusion of male and female genetic material.

Segment Nation Nucleus

The nucleus formed by the fusion of male and female pronuclei during fertilization.

Fraternal Twins

Non-identical dizygotic twins resulting from the release and fertilization of two separate eggs.

Paternal Twins

Identical twins resulting from a single fertilized egg (zygote) that divides early into two separate parts.

Conceptus

The term for the zygote and its associated membranes as it undergoes rapid mitosis.

Cleavage

A stage of rapid mitosis where the number of cells increases (every 5 or 6 cycles) while the total volume of cells remains the same.

Blastocyst

A hollow ball of cells ($70 imes 100$ cells) surrounding a central cavity called a blastocoel.

Trophoblast

The outer covering of cells in a blastocyst, located just beneath the zona pellucida, that will contribute to the placenta.

Inner Cell Mass

The cluster of cells within the blastocyst that is totipotent and will eventually form the embryonic body.

Blastocoel

The internal fluid-filled cavity within the blastocyst.

Morula

The embryonic stage consisting of a solid ball of exactly 16 cells.

Cytotrophoblast

The inner layer of the trophoblast composed of distinct boundary cells.

Syncytiotrophoblast

The outer layer of the trophoblast that lacks boundary cells and makes the direct contact with the endometrium during implantation.

Gastrulation

The developmental process occurring after 8 weeks involving the formation of the three primary germ layers.

Ectoderm

The outermost germinal layer that develops into the epidermis and central nervous system organs.

Endoderm

The innermost germinal layer that forms mucosal linings, the digestive system, liver, pancreas, and inner layers of the lungs.

Mesoderm

The middle germinal layer that forms muscles, bones, the circulatory system, and many internal organs.

Yolk Sac

An extraembryonic membrane lined with endoderm that serves as the primary source of nourishment and early blood formation.

Amnion

A thin protective membrane that encases the embryo in a cavity filled with amniotic fluid.

Chorion

An extraembryonic membrane derived from the trophoblast that completely surrounds the fetus and forms a major portion of the placenta.

Allantois

A small vascular outcrop of the yolk sac involved in early blood formation and the development of the umbilical cord.

Wharton’s Jelly

The supporting connective tissue found within the umbilical cord.

Chorionic Villi

Fetal blood vessel-containing structures that extend into maternal intervillous spaces for gas and nutrient exchange.

Decidua Basalis

The maternal portion of the placenta located on the endometrium.

Placenta Previa

A condition where the placenta covers the cervix, potentially obstructing a proper birth.

Human Chorionic Gonadotropin (hCG)

A hormone initially secreted to maintain the corpus luteum; it may cause morning sickness and stimulates male fetal testosterone secretion.

Relaxin

A hormone that increases the elasticity of the pubic symphysis and aids in dilating the cervix.

Dilation Stage

The first stage of labor involving regular contractions and the widening of the cervix to $10 ext{ cm}$.

Puerperium

The period lasting six weeks post-delivery during which maternal reproductive organs return to their normal state.

Involution

The process of tissue catabolism in the uterus following birth.

Lochia

Uterine discharge containing blood and mucus that continues for about 4 weeks post-partum.

Ductus Arteriosus

A fetal blood vessel that constricts immediately after birth to allow blood flow to the lungs via the pulmonary arteries.

Foramen Ovale

An opening in the fetal heart that closes after birth to leave a depression called the fossa ovalis.

Ductus Venosus

A fetal vessel that degenerates after birth to become the ligamentum venosum.