Lecture 13 10/17/23

Question 1

What are two important characteristics of the fetus?

Answer 1

-lungs are non-functional
-placenta allows for nutrient/waste exchange

Question 2

What are the characteristics of the umbilical arteries?

Answer 2

-originate on the internal iliac arteries
-take blood from fetus to placenta

Question 3

What do the umbilical arteries become in adults?

Answer 3

round ligaments of the bladder

Question 4

What is the role of the umbilical vein?

Answer 4

take blood from placenta to fetus

Question 5

What does the umbilical vein become in adults?

Answer 5

round ligament of the liver

Question 6

What is the role of the ductus venosus?

Answer 6

allow blood to bypass the liver

Question 7

Why does the ductus venosus bypass the liver?

Answer 7

because the blood passing through it does not need to be filtered

Question 8

What does the ductus venosus become in adults?

Answer 8

ligamentum venosum

Question 9

Why is the hepatic portal vein blood filtered in the fetus?

Answer 9

to keep the filtration system functional

Question 10

What are the characteristics of fetal lungs?

Answer 10

-collapsed
-blood vessels are open
-need some circulation
-collapse provides resistance to blood flow

Question 11

What does the foramen ovale become in adults?

Answer 11

fossa ovalis

Question 11

What are the characteristics of the foramen ovale?

Answer 11

-right to left shunt
-collapsed lungs create higher pressure in RA than LA
-one-way valve

Question 12

What are the characteristics of the ductus arteriosus?

Answer 12

-right to left shunt
-takes excess blood from pulmonary artery to aortic arch

Question 13

What does the ductus arteriosus become in adults?

Answer 13

ligamentum arteriosum

Question 14

What happens when a neonate takes its first breath?

Answer 14

-resistance through the lungs drops
-oxygen content in the blood rises

Question 15

What happens as a result of more blood coming into the LA after birth?

Answer 15

-pressure in the LA increases
-foramen ovale is forced closed

Question 16

How does oxygen impact the fetal structures?

Answer 16

-increased O2 tension causes contraction of the special smooth muscle in the ductus arteriosus, ductus venosus, umbilical vein, and umbilical arteries
-this contraction causes the structures to close off

Question 17

What does it mean for a structure to be probe patent?

Answer 17

-it appears closed, but a probe can still be pushed through
-structure isn’t fully sealed

Question 18

How long does it take for the fetal structures to fully close?

Answer 18

about 2 weeks

Question 19

What allows the fetal structures to fully close?

Answer 19

development of scar tissue

Question 20

What is the falciform ligament?

Answer 20

fatty structure that surrounds the umbilical vein

Question 21

What is the median ligament of the bladder?

Answer 21

peritoneal flap over the umbilical arteries

Question 22

Why is it okay that the majority of the blood circulating through the fetus is deoxygenated?

Answer 22

the fetus does not have a need for a lot of oxygen because it is not moving much

Question 23

How many sources contribute deoxygenated blood to circulation?

Answer 23

four