L12: Placenta

Question 1

functions of the placenta

Answer 1

1. diffuse O2 and CO2
2. diffuse foodstuffs
3. excrete waste

Question 2

early placenta properties

Answer 2

thick
low permeability
small surface area
total diffusion conductance is low

Question 3

late placenta properties

Answer 3

thin
high permeability
large SA
large increase in placental diffusion

Question 4

what is the oxygen pressure gradient near the end of pregnancy

Answer 4

pO2 mom = 50 mmHg
pO2 babe = 30 mmHg

gradient pressure = 20

Question 5

how can adequate oxygenation occur w/ such ____ pressure gradient between mother and fetus?

Answer 5

low gradient

1. fetal Hb has higher O2 affinity
2. fetal Hb conc is 50% greater
3. bohr effect

Question 6

HCG

Answer 6

human chorionic gonadotropin

secreted by syncytial trophoblast cells into maternal fluids

Question 7

HCG functions

Answer 7

1. prevent involution of corpus luteum
2. cause CL to increase secretion of progesterone/estrogens
3. cause increased CL growth
4. exert interstitial cell-stimulating effect on testes of male fetus

Question 8

what is the result of HCG exerting interstitial cell-stimulating effect on testes of male fetuses?

Answer 8

results in production of testosterone until birth

Question 9

progesterone

Answer 9

early - CL secretes small amount

later - placenta secretes large amounts

Question 10

progesterone functions

Answer 10

1. cause decidual cells to develop into endometrium
2. decrease contractility of pregnant uterus
3. increase secretions of fallopian tube, uterus

may work w/ estrogen to prep breasts for lactation

Question 11

HCS

Answer 11

human chorionic somatomammotropin

secreted by placenta starting in week5

Question 12

HCS functions

Answer 12

1. cause decreased insulin sensitivity, decreased glucose use by mother
2. general metabolic hormone

Question 13

define malformations

Answer 13

primary errors of morphogenesis

usually multifactorial, involved any number of genetic and/or environmental factors

Question 14

define disruptions

Answer 14

disturbances in otherwise normal development

ex. amniotic bands

Question 15

define deformations

Answer 15

disturbances in normal development

typically caused by abnormal biomechanical forces such as uterine constraints

ex. clubfoot

Question 16

define sequences

Answer 16

series of events triggered by 1 factor

ex. oligohydramnios

Question 17

oligohydramnios

Answer 17

decreased amniotic fluid

leads to variety of events including:
fetal compression and problems from this

Question 18

defines syndromes

Answer 18

constellations of congenital anomalies that are thought to be pathologically related but cannot be explained by 1 event

often caused by viral infections

Question 19

turner syndrome

Answer 19

X0 genotypes
45 chr, only 1 X

female w/ underdeveloped sex
low hairline
broad chest
folds on neck
usually sterile
normal intelligence

Question 20

poly-X syndrome

Answer 20

XXX

tall and thin
often fertile
most are normal intelligence

Question 21

environmental factors causing abnormalities

Answer 21

infection (virus, bacteria, protozoans)
radiation
maternal diabetes
drugs/chemicals

Question 22

thalidomide

Answer 22

text????

Question 23

alcohol

Answer 23

go review fetal alcohol syndrome

Question 24

retinoic acid

Answer 24

refer to lectures on signaling pathways and Hox genes

Question 25

folic acid

Answer 25

text ????

Question 26

maternal factors that result in fetal growth restrictions

Answer 26

preeclampsia chronic hypertension drugs, narcotics, alcohol, nicotine malnutrition

Question 27

fetal hydrops

Answer 27

refers to accumulation of edema fluid in fetus during intrauterine growth causes: hemolytic anemia immune hydrops nonimmune hydrops

Question 28

immune hydrops is caused by ?

Answer 28

blood group incompatibility between mom and babe fetal RBCs reach mom blood stream during last trimester or birth major factor: D ag of Rh group