Development of the Heart

Question 1

The truncus arteriosis becomes the

Answer 1

Ascending aorta and the pulmonary trunk

Question 2

The bulbus (conus) cordis becomes the

Answer 2

Right ventricle outflow tract

Question 3

The primitive ventricle becomes

Answer 3

The left and right ventricles

Question 4

The primitive atrium becomes the

Answer 4

R and L auricles

Question 5

The sinus venosis becomes the

Answer 5

R ventricle and L coronary sinus (SVC/IVC and coronary sinus)

Question 6

The bulboventricular loop becomes

Answer 6

The bulk of both ventricles

Question 7

The vitelline veins become part of the

Answer 7

Hepatic portal system

Question 8

The anterior and posterior cardinal veins drain

Answer 8

The embryo

Question 9

The common cardinal vein drains

Answer 9

directly into the sinus venosis

Question 10

What happens to arches 1-6

Answer 10

1, 2, and 5 disappear 3 and 4 become the aorta and its derivatives 6 becomes a pulmonary trunk

Aortic arch 3 becomes the distal end of the common carotid as well as the interal carotid

Aortic arch 4 on the left becomes a part of the aortic arch and on the right it becomes a part of the subclavian

Aortic arch 6 becomes the pulmonary arteries on both sides, whiel the distal end of the left 6th aortic arch becomes the ductus arteriosis

The pulmonary trunk comes from the aortic sack that fed the 6th aortic arch

Question 11

The rough-walled part of the atrium is from ___ The smooth walled part of the atrium is

Answer 11

From embryonic atrium From venous origin

Question 12

On the right side of the heart, the original atrium becomes

Answer 12

Auricle

Question 13

The bulk of the atrium comes by

Answer 13

Incorporating the single early pulmonary vein into the sinus venerium portion of the left atrium

Question 14

Identify the parts and what they become

Answer 14

Purple: Truncus arteriosus –> Asc. aorta and pulmonary trunk

Blue: Bulbus (conus) cordis –> R. ventricle outflow track

Green: Primitive ventricle –> R and L Ventricles

Yellow: Primitive Atrium –> R and L auricles

Teal: Sinus Venosus –> R ventrilce and L coronary sinus

Question 15

What role does the following feature play in embryonic/fetal heart function: Septum primum

Answer 15

First septum that grows

Resides as border in left atrium

Question 16

What role does the following feature play in embryonic/fetal heart function: Foramen primum

Answer 16

Eventually becomes valve of foramen ovails

Question 17

What role does the following feature play in embryonic/fetal heart function: Septum secundum

Answer 17

Ricker, rigid septum gorwing up the sides as a wall for the right atrium

Forms the endodermal cushion

Question 18

What role does the following feature play in embryonic/fetal heart function: Froamen secundum

Answer 18

Evenually becomes the foramen ovale

Question 19

What role does the following feature play in embryonic/fetal heart function: Foramen ovale

Answer 19

Allows IVC blood to travel from left to right

Closes when septum secundum fuses with septum primum

Question 20

Explain the development of the adult IV septum, as well as the valves

Answer 20

IV septum grows superiorly towards the endocardial cushion

It stops and allows a foramen for blood to transfer from right to left

That foramen eventually fuses

Original IV septum becomes the muscular IV septum and the mesoderm fuses with the endocardial cushion to form the membranous IV septum

The AV valves form from the leftover endocardial tissue

Question 21

Why is the truncus septum spiral?

Answer 21

Truncus septum must be spiral because during development, the 6th aortic arches become the pulmonary trunk/arteries

These arches lie posterior to the bulboventricular loop

In order for the right ventricle to properly supply the 6th aortic arches/pulmonary trunk, the truncus septum must begin to spiral to allow blood flow from the front to reach the back