Cardiac development

Question 1

Morphogenesis of the heart

Answer 1

cells arise from the lateral mesoderm, move to the midline in 2 waves, and create a crescent of cells.

Question 2

First and second heart fields are developed by Day

Answer 2

15

Question 3

Developing heart tube loops ventrally and to the right by Day

Answer 3

20

Question 4

Individual chambers of the heart are forming by Day

Answer 4

28

Question 5

There are 4 individual chambers of the heart by day

Answer 5

50

Question 6

What adaptations allow for in-utero oxygen delivery to the developing fetus?

Answer 6

1. fetus has elevated hematocrit and oxygen carrying capacity.
2. Fetal Hb binds O2 more tightly than maternal Hb.
3. Fetal Hb has a lower P50 than maternal Hb

Question 7

In utero lung pressure

Answer 7

it is a high blood pressure system, due to vasoconstriction.

Question 8

in utero placenta pressure

Answer 8

is a low pressure system

Question 9

Fetal circulation relied on 4 adaptations:

Answer 9

1. umbilical vein.
2. Ductus venosus.
3. Foramen Ovale.
4. Ductus arteriosus

Question 10

Ductus arterioles becomes

Answer 10

Ligamentum arteriosum

Question 11

Foramen ovale becomes

Answer 11

fossa ovalis

Question 12

Ductus venous becomes

Answer 12

ligamentum venosum

Question 13

umbilical vein becomes

Answer 13

ligamentum teres

Question 14

In utero the heart functions as

Answer 14

2 parallel circuits. Fetal lungs are filled with fluid, not air and oxygen delivery is via the placenta.

Question 15

After birth, heart functions as

Answer 15

2 circuits in series. Baby’s lungs are filled with air, oxygen delivery is via the lungs because the placenta is removed.

Question 16

When lungs fill with air, what happens to the pulmonary vascular resistance?

Answer 16

It decreases

Question 17

When the placenta is removed, what happens to systemic resistance?

Answer 17

it increases

Question 18

Why does the foramen ovale close?

Answer 18

Increased pressure in the Left atrium