OB Ch. 10 Fetal Development and genetics

Question 1

Stages of Fetal Development

Answer 1

-zygotic stage
-blastocyst stage
-embryonic stage
-fetal stage

Question 2

zygotic stage

Answer 2

-conception
-fertilization of egg via sperm
-sperm are determiner for sex (X or Y carrier)

Question 3

fertilization occurs where

Answer 3

-fallopian tube
-zygote travels from fallopian tube to uterus via tubular movement

Question 4

zygote undergoes cleavage and turns into…

Answer 4

-MORULA
-morula reached uterine cavity 72 hours after fertilization

Question 5

Blastocyst stage

Answer 5

-morula cleaves and becomes more solid mass that attaches to uterine cavity
-nutrient rich fluid enters uterine cavity

Question 6

inner surface of blastocyst forms..

Answer 6

embryo and amnion

Question 7

trophoblast

Answer 7

-outer layer surrounding blastocyst
-attaches itself to endometrium for more nourishment
-will eventually attach itself to upper fundus d/t rich blood supply
-develops into chorion and helps form placenta

Question 8

embryonic stage lasts from

Answer 8

end of 2nd week to 8th week
-major structures and organs begin to develop, main external features

Question 9

ectoderm forms into

Answer 9

CNS, special senses, skin, glands, amnion

Question 10

amnion is..

Answer 10

thin membrane filled with amniotic fluid

Question 11

mesoderm forms…

Answer 11

skeletal, urinary, circulatory, and reproductive organs

Question 12

ECTODERM forms…

Answer 12

respiratory system, liver, pancreas, digestive

Question 13

fetal stage

Answer 13

differentiation and structures specialize by end of the 8th week

Question 14

role of amniotic fluid

Answer 14

-thermoregulation for fetus
-permits symmetric growth and development
-cushion for fetus from trauma
-allows umbilical cord to be relatively free from compression

Question 15

amniotic fluid derived from…

Answer 15

-fetal urine
-fluid from maternal blood source across amnion

Question 16

amniotic fluid increases in volume throughout pregnancy. By term, should be

Answer 16

1000 mL or 1 L

Question 17

oligohydramnios

Answer 17

-decreased amniotic fluid
-500 mL or less
-DXed via ultrasound

Question 18

what conditions are associated with oligohydramnios

Answer 18

-uteroplacental insufficiency
-fetal renal abnormality

Question 19

Oligohydramnios: Fetus is at risk for

Answer 19

-low birth weight
-surgical birth

Question 20

Polyhydramnios

Answer 20

-excess amniotic fluid
-2 L or more at birth
-DXed with ultrasound

Question 21

what conditions are associated with polyhydramnios

Answer 21

-maternal diabetes
-neural tube defects
-chromosomal deviations
-malformations of GI or CNS

Question 22

Polyhydramnios: fetus at risk for…

Answer 22

premature rupture of fluid membranes d/t uterine overdistention

Question 23

umbilical cord characteristics

Answer 23

-formed from amnion
-contains 1 large vein and 2 small arteries

Question 24

Wharton jelly is…

Answer 24

-white jelly surrounding all 3 blood vessels in umbilical cord to prevent compression
-if cord compresses, blood supply and nutrients would be cut off to fetus

Question 25

Maternal uterine arteries deliver…

Answer 25

nutrients to placenta

Question 26

Maternal uterine vein carries…

Answer 26

fetal waste products away

Question 27

Placenta Functions

Answer 27

-serves as interface between mother and fetus
-if something is wrong with placenta…something is wrong with fetus
-produces hormones to control physiology of mother to ensure fetus is supplied with adequate nutrients and O2 for growth
-placenta acts as lungs during gestation; fetal rungs are non functional
-protect fetus from immune attack by the mother
-remove waste products from fetus
-induce mother to bring more nutrients to placenta
-promotes hormones that mature into fetal organs

Question 28

Placenta Characteristics

Answer 28

-formed by week 12
-rough side faces mother (amniotic membrane)
-smooth side faces baby

Question 29

Do maternal and fetal blood mix?

Answer 29

NO! they should not mix d/t placental barrier

Question 30

what is the placental barrier

Answer 30

fetal tissues that separate the materal and fetal blood

Question 31

Shunt does what?

Answer 31

-delivers oxygen rich venous blood to systemic circulation and ensures that oxygen poor venous blood bypasses pulmonary circulation

Question 32

when does lung development finish?

Answer 32

AT BIRTH

Question 33

fetal circulation pathway for oxygenated blood

Answer 33

-oxygen rich blood carried from placenta to fetus via umbilical vein
-half goes to hepatic arteries, other half goes to ductus venosus in IVC
-blood from vena cava deflected via foramen ovale into LA –> LV –> ascending aorta –> head and upper body

Question 34

fetal circulation pathway for deoxygenated blood

Answer 34

-SVC–> RA–> RV –> pulmonary artery –> ductus arteriosus –> descending aorta –> placenta (for oxygenation)
-only 5-10% of blood goes to lungs d/t pulmonary resistance b/c fetal lungs are filled with fluid and nonfunctional

Question 35

what happens to lungs at birth

Answer 35

-with first breath, lungs inflate, leads to increase in blood flow from lungs to RV
-pressure increases in LA (left side of foramen ovale presses against opening and creates functional separation between 2 atria)
-blood goes to RV as it can no longer be bypassed (reason for increased blood flow to lungs)
-RV pumps blood into pulmonary artery, which goes to lungs for oxygenation and back to LV