Embryology of the Heart

Question 1

Angioblastic Cords

Answer 1

Where the body cavities form and arrange themselves side by side
Form the 2 endocardial tubes

Question 2

Endocardial Tubes

Answer 2

Filled with cardiac jelly
Lateral fold brings the 2 tubes together to form 1 tube
Start the blood flow

Question 3

1 Tube from Endocardial Tube forms what?

Answer 3

4 chambers of the heart

Question 4

Cardiac Jelly

Answer 4

develop into the valves of the heart

Question 5

Early blood flow of the heart

Answer 5

1. Sinus Venosus
2. Primitive Atria
3. Primitive Ventricle
4. Bulbus Cordis
5. Truncus Arteriosus
6. Aortic Sac

Question 6

Where does blood come from embryologically?

Answer 6

The mother via umbilical cord, caudal end

Question 7

Bulboventricular Loop

Answer 7

twist/bend of the heart
Atrium and sinus venosus move dorsal
Inflow moved to back of the heart
Outflow moved to front of the heart

Question 8

Sinus Venosus

Answer 8

Main drain vein of embryo heart
Receives venous blood ergo it makes the SVC and IVC in adult heart
Plays major roll in developing right atrium

Question 9

Where do the semi-lunar valves form?

Answer 9

Between the bulbus cordis and truncus arteriosus

Question 10

What forms the atrioventricular valves?

Answer 10

Cardiac jelly

Question 11

How does the primordial atrium form?

Answer 11

Comes from part of endocardial tube

1. Septum premum formation
2. Leaves a hole = foramen premum
3. Spetum secundum comes down on right side
4. Septum premum and septum secundum attach to close off foramen premum
5. Septum secundum realizes still need a hole for blood flow
6. Formation of foramen secundum = foramen ovale

Question 12

Foramen Ovale

Answer 12

Closes off at birth due to left pressure being greater than right so a flap comes down and covers the hole.
Becomes fossa ovalis

Question 13

What forms the right atrium?

Answer 13

sinus venosus

Question 14

What forms the Right and Left horns of the atrium?

Answer 14

Sinus venosus

Question 15

What does the Left horn become?

Answer 15

coronary sinus in the right atrium

Question 16

What does the right horn become?

Answer 16

sinus venarum = smooth muscle of the right atrium

Question 17

What from the pectinate muscles in right atrium?

Answer 17

primitive atria

Question 18

What does the coronary sinus separate in the adult heart?

Answer 18

atria from the ventricles

Question 19

What forms the left atrium?

Answer 19

4 pulmonary vessels

The left atrium is so smooth because it came from veins

Question 20

What does the left primitive atria become?

Answer 20

left auricle

Question 21

How does the primordial ventricle change to adult ventricles?

Answer 21

Have the superior and inferior portion of the interventricular septum grow together and form right and left ventricles
This is where VSD’s occur when the growing is deficient

Question 22

What does the interventricular septum require for proper growth?

Answer 22

endocardial cushions = spot welders that come in from the side

Question 23

What does the truncus arteriosus become?

Answer 23

ascending aorta and pulmonary trunk

Question 24

What does the bulbus cordis become?

Answer 24

conus arteriosus of the right ventricle and the aortic vestibule in the left ventricle

Question 25

How does the outflow of blood form?

Answer 25

Partition the truncus arteriosus and the bulbus cordis
the 2 partitions form ridges that come together and spiral
the spiral motion causes the outflow to split

Question 26

What is different about fetal circulation?

Answer 26

Bypass the lungs because use the mothers blood which is already oxygenated

Question 27

What structure allows blood to bypass the lungs?

Answer 27

ductus arteriosus

Question 28

Which side of the heart has higher pressure before birth?

Answer 28

Right side and after birth the left side as higher pressure