Chapter 3.3

Question 1

Which blood has higher partial pressure? Maternal blood or fetal blood?

Answer 1

• there is a higher partial pressure of oxygen in maternal blood than fetal blood
• > therefore, nutrients and waste in the blood move by diffusion
• > from a higher gradient to a lower one

Question 2

Describe the difference between fetal hemoglobin and adult hemoglobin

Answer 2

-fetal hemoglobin exhibits greater affinity for oxygen

Question 3

What are the roles of the placental barrier?

Answer 3

1) immune protection
- >crossing of antibodies across the placenta serves a protective function

2) Placenta is an endocrine organ
- >it produces progestorone, estrogen and hCG

Question 4

Does oxygenation occur at fetal lungs? If not, where does it occur?

Answer 4

• no

- >it occurs at the placenta

Question 5

Does the fetus depend on its lungs and liver

Answer 5

• no
• > detoxification and metabolism are primarily controlled by the mother’s liver

-nutrient and waste exchange occurs at the placenta

Question 6

Why does the fetus develop shunts

Answer 6

• because its lungs and liver are underdeveloped

- >therefore, the baby is sensitive to high blood pressure

Question 7

Describe the three types of shunts in a baby

Answer 7

1) foramen ovale
- >one way valve
- >connects the right atrium to the left atrium
- >allows blood entering the right atrium to flow into the left atrium instead of the right ventricle
- note in fetuses, the right side of the heart is at a higher pressure than the left

2) Ductus arteriosus
- >shunts leftover blood from the pulmonary artery to the aorta

3) Ductus venosus
- >liver is bypassed
- >blood returning from the placenta via the umbilical vein goes directly to the inferior vena cava