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Unformatted text preview: CONCEPTION AND DEVELOPMENT Key Terms: • Amnion: o A thin membrane containing amniotic fluid or “Bag of Waters” o Inner layer of the placenta • Amniotic Fluid o Acts as a cushion to protect fetus from injury, controls temperature, helps prevent cord compression, and allows fro movement and growth and development of fetus. o Amniotic fluid is secreted from the trophoblast or embryo and later from the fetal kidneys and lungs o Fluid constantly changes as a result of movement o Alkaline w/ pH of 7 and contains many nutrients and substances o Clear milky looking • Blastocyst o Formed after the morula o Possess an inner cell mass that eventually will become the embryo • Cellular Multiplication o Occurs as fertilized ovum is transported through the fallopian tubes • Chorion o The first and outermost layer to form from the trpohoblast with chorionic villi at surface o Outer layer of the placenta • Chorionic Villi o Sprouts from chorion in order to provide maximum surface area contact with maternal blood • Cotyledon o The lobes and sections that make up the placenta o 15-20 segments • Ductus Arteriosus o In a developing fetus-a shunt connecting the pulmonary artery to the aortic arch o Allows most blood from the right ventricle to bypass the fetus’ fluid filled lungs o Protects lungs from being overworked and allows right ventricle to strengthen • Ductus Venosis o Shunts most (80%) of blood flow from the umbilical vein directly to inferior vena cava o Allows oxygenated blood from the placenta to bypass the liver and plays a critical role in shunting oxygenated blood to the fetal brain • Ectoderm o Primary germ layer o Forms skin, sweat glands, sebaceous glands, nails, hair, lens of eye, CNS, nasal cavity, tooth enamel, mammary glands, and pituitary gland • Endoderm o Primary germ layer o Forms the vagina, bladder, urethra, liver, pancreas, lining of the digestive tract, epithelium or various organisms • Embryo o Stage of baby 3-8 weeks • Endometrium o The lining of the uterus o During pregnancy- the trophoblastic layer forms finger like projections called villi that grow into the endometrium. This makes the endometrium thicker and increases vascularity under the influences of estrogen and progesterone o Becomes the decidua (uterine lining) after implantation and becomes part of the placenta • Estrogen o Produced by the placenta throughout pregnancy and levels increase steadily until birth o Regulates production of progesterone o Growth of uterus and breasts • Fertilization o When the mature ovum and sperm unite Ovum lives up to 12-24 hours and sperm lives up to 72 hours...
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This note was uploaded on 04/14/2011 for the course NURS 101 taught by Professor Carlson during the Spring '11 term at Saint Louis.
- Spring '11