Nursing Care During Normal Pregnancy and Care of the Developing Fetus

Vocabulary practice flashcards covering terminology, stages of fetal growth, embryonic layers, placental structures, and fetal circulation from Chapter 9.

Ovum

The stage of fetal growth extending from ovulation to fertilization.

Zygote

The stage of fetal growth extending from fertilization to implantation.

Embryo

The stage of fetal growth extending from implantation to $5\text{--}8\,weeks$.

Fetus

The stage of fetal growth extending from $5\text{--}8\,weeks$ until term.

Conceptus

The developing embryo and placental structures throughout pregnancy.

Age of Viability

The earliest age at which fetuses survive if born, generally accepted as $24\,weeks$ or when weighing more than $500\text{--}600\,g$.

Pre-embryonic Stage

The first $2\,weeks$ ($14\,days$) of fetal development beginning with fertilization.

Fertilization

The union of the ovum and spermatozoon, occurring in the outer third of the fallopian tube (ampulla).

Embryonic Stage

The developmental stage from day $15$ (implantation) to $8\,weeks$ post-conception, or until crown-rump length reaches $3\,cm$.

Hyaluronidase

An enzyme released by sperm to penetrate the corona radiata of the ovum.

Acrosin

An enzyme secreted by sperm to dissolve the zona pellucida of the ovum.

Morula

A $16\text{--}50\,cell$ mass produced within $3\,days$ of fertilization that remains surrounded by the zona pellucida.

Blastocyst

The cell structure formed upon entering the uterine cavity, containing a blastocele, an inner embryoblast, and an outer trophoblast.

Embryoblast

The inner cell mass located inside the blastocele that gives rise to the embryo.

Trophoblast

The outer cell layer of the blastocyst that develops into the placenta.

Implantation

The process occurring $8\text{--}10\,days$ after fertilization where trophoblast cells erode, engulf, and embed into the uterine lining.

Decidua

The name given to the uterine endometrium after implantation has occurred.

Decidua Basalis

The portion of the uterine decidua located directly beneath the blastocyst.

Decidua Capsularis

The portion of the uterine decidua directly covering the embedded blastocyst.

Decidua Vera

The portion of the uterine decidua lining the remainder of the uterine cavity.

Chorion

The outer fetal membrane formed from the trophoblast that contains chorionic villi on its surface.

Amnion

The inner membrane developing from the blastocyst inner cell mass that forms a protective, fluid-filled sac around the embryo.

Oligohydramnios

An abnormally low amniotic fluid volume of less than $300\,mL$, which is associated with fetal renal abnormalities.

Hydramnios

An excessive amniotic fluid volume exceeding $2\,L$, which is associated with fetal gastrointestinal and other malformations.

Wharton's Jelly

A rich extracellular matrix of hyaluronic acid, chondroitin sulfate, and collagen that prevents umbilical blood vessels from collapsing, kinking, or compressing.

Syncytiotrophoblast

The outer functional layer of placental trophoblast cells that produces hormones such as hCG, hPL, estrogen, and progesterone.

Langhans' Layer

The inner cytotrophoblast layer that protects the embryo and fetus from infectious diseases until it disappears between weeks $20\text{--}24$ of gestation.

Cotyledons

The $15\text{--}20$ individual compartments of the placenta created by anchoring septa, each containing branching chorionic villi and fetal vessels.

Human Chorionic Gonadotropin (hCG)

A placental hormone that preserves corpus luteum function and suppresses maternal immunologic responses against placental tissue.

Human Placental Lactogen (hPL)

A placental hormone that alters maternal metabolism, increases insulin resistance, and facilitates glucose transfer across the placental membrane.

Ectoderm

The outer primary germ layer that gives rise to the nervous systems, skin, hair, nails, sense organs, mucous membranes, and tooth enamel.

Mesoderm

The middle primary germ layer that forms connective tissue, bones, muscles, heart, circulatory system, blood cells, kidneys, ureters, and reproductive system.

Endoderm

The inner primary germ layer that forms the epithelial lining of the digestive tract, respiratory tract, urinary bladder, urethra, and associated glands.

Ductus Venosus

A fetal blood vessel shunt that directs oxygenated blood from the umbilical vein into the inferior vena cava, bypassing the liver.

Foramen Ovale

An opening in the interatrial septum of the fetal heart allowing blood to bypass the right ventricle and flow directly from the right atrium to the left atrium.

Ductus Arteriosus

A vascular shunt in the fetus connecting the pulmonary artery directly to the aorta, bypassing the uninflated lungs.

Fetal Circulation

The specialized circulatory system of the fetus utilizing three shunts (ductus venosus, foramen ovale, ductus arteriosus) to circulate oxygenated blood from the placenta.

Quickening

The maternal perception of fetal movement, typically first noted during the 5th month ($17\text{--}20\,weeks$) of gestation.