Conception and Prenatal Development

Created by jcvecere 

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23 terms

The fetal period begins and ends

9 weeks after conception and ends with birth

week 9 through 12

head 1/2 total length of the fetus; contents enter the abdomen;fetus begins producing urine and excretes it into the amniotic fluid; fetal gender can be determined by the end of this period.

week 13 through 16

quickening is felt, normally by women who have been pregnan before. fetus grows rapidly in length; face looks human, eyes and ears positioned.

weeks 17 through 20

changes in hair and skin; Vernix caseosa fatty cheese like substance secreted by fetus sebaceous gland;lanugo-fine hair covers the body;brown fat;heat producing fat is on the back of the neck,behind the sternum and around the kidneys(maintains temp) vernix diminishes around 38-39 weeks

weeks 21 through 24

minimal sub q fat; skin translucent and red;lungs produce surfactant, reduces surface tension and prevents collapsing.; capillary network still immature; fetus less likely to survive if delivered here.

weeks 25 through 28

fetus more likely to survive as maturation of lungs, cns, pulmonary; blood formation shifts from spleen to bone marrow, eyes reopen; usually assume a head down position; better likely hood to survive

weeks 29 through 32

skin is pigmented to race, toenails and finger nails present fetus has more sub q fat, good chance of survival at this gesstation; 29 weeks may need ventilator

weeks 33 through 38

growth continues but slows as the fetus reaches full term; primarily gainging weight; pulmonary system matures; large amt of sub q fat; vernix and lanugo diminish, testes decend(maturation of all systems)

Auxillary structures; placenta side 1

maternal side attaches towards the fundus; EXCHANGE OF SUBSTANCES OCCURS WITHIN THE INTERVILLOUS SPACE; transports O2 and nutrients and rids of waste-fetal heart cirulates the blood.

Auxillary structures;placenta side 2

Fetal side; blood is transported from the fetus to the fetal side of the placenta by two umbilical arteries and one vein blood is circulated to and from the fetal side of the placenta by the fetal heart.

Placenta has how many veins and how many arteries

2 umbilical arteries and 1 vein

The Placenta produces

glycogen, cholesterol, fatty acids; exchanges O2 and CO2, rids of waste and exchanges nutrients

Placental hormones and IgG

hormones; Estrogen, Progesterone ( hormone of pregnancy) HPL- human placental lactagon; IgG provides passive immunity against disease.

Fetal membranes and amniotic fluid

fluid-protects umbilical cord; amnion and chorion-so close they look like one layer.Amniotic fluid cushions, maintains temp, sysemic development protects fetal parts, room and buoyancy; need adequate fluid for baby lung support

Amniotic fluid is made up of

fetal urine and fluid transported by maternal blood

Oligohydramnios

less than 50% expected ; 10-12 pockets normal fluid lower must have more than 1 ultrasound to diagnose

Hydramnios(polyhydramnios)

excesssive fluid, may exceed 2000ml; can cause rupture which detaches placenta causes harm to cord.

Fetal circulation

2 arteries carry away deoxygenated blood and waste away from fetus; 1 vein carry oxygenated and nutrient rich blood to the fetus

Whartons jelly

cushions cord from compression(thick substance that covers the cord)

Ductus venosus

first shunt; about half the blood goes through the liver and the rest bypasses the liver and enters the inferior vena cava thought this shunt

Foramen ovale

second shunt; most of the blood passes directly into the left atrium through this shunt

Ductus arteriosis

third shunt; the rest of the blood from the right ventricle joins oxygenated blood in the aorta through this shunt.

what plays a big role while pregnant

Age; due to diabetes, hypertension, smoking can cause a skinny cord.

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