13: Physio Of Pregnancy And Fetus

Question 1

Three major features of the placenta for exchange

Answer 1

1. Chorionic villi
2. Intervillous space filled with blood from spiral A’s
3. Decidua basalis

Question 2

Purpose of intervillous space

Answer 2

Dissipates force of blood/reduces velocity, allowing adequate time for exchange of nutrients

Question 3

Where does blood drain from the intervillous space?

Answer 3

Placental veins

Question 4

Umbilical arteries carry…?

Answer 4

Deox blood

Question 5

Fetal blood flow from umbilical arteries

Answer 5

Umbilical arteries -> branch and penetrate chorion to form chorionic villi capillary network -> obtain O2/nutrients -> return to fetus through umbilical vein

Question 6

What is the pO2 of blood in intervillous space?

Answer 6

30-35mmHg

Question 7

What two things are transferred via passive exchange between mother and fetus

Answer 7

1. Nitrogenous waste

2. Lipid soluble hormones

Question 8

What is transferred to fetus via facilitated diffusion

Answer 8

Glucose

Question 9

What three things are transferred to fetus via primary and secondary active transport?

Answer 9

AAs, vitamins, minerals

Question 10

What is transferred to fetus via receptor-mediated endocytosis

Answer 10

Large molecules (ex: LDL, hormones, Abs)

Question 11

What can the placenta manufacture?

Answer 11

Steroid hormones, amines, polypeptide hormones and nts, proteins and glycoproteins

Question 12

Five general functions of placental hormones

Answer 12

1. Maintain pregnant uterus
2. Stimulate growth of maternal breasts
3. Adapt aspects of maternal metabolism
4. Regulate fetal development
5. Regulate timing and progression of parturition

Question 13

Accumulation of hCG in maternal circulation

Answer 13

Rapidly accumulates in early pregnancy, doubling daily up to the 10th week

Question 14

What is thought to cause morning sickness?

Answer 14

HCG

Question 15

Two names of hPL

Answer 15

Human placental lactogen, human chorionic somatomammotropin

Question 16

When is hPL detected in syncytiotrophoblast and in maternal serum?

Answer 16

Syncytiotrophoblast: day 10

Maternal serum: week 3

Question 17

Umbilical veins vs arteries

Answer 17

Umbilical vein: oxygenated blood to fetus

Umbilical arteries: deox blood/CO2/waste to placenta

Question 18

Function of the fetal circulatory shunts

Answer 18

Bypass liver and lungs, which aren’t fully functional until late pregnancy/just after birth

Question 19

What type of shunt is the ductus arteriosus

Answer 19

Right to left

Question 20

Are ductus arteriosus and ductus venosus complete shunts?

Answer 20

No, some blood still gets through to supply the lungs and liver