Embryology

Question 1

What is the name of the remnant of the ductus arteriosus?

Answer 1

Ligamentum arteriosum

Question 2

What is the name of the remnant of the ductus venosus?

Answer 2

Ligamentum venosum

Question 3

What is the name of the remnant of the foramen ovale?

Answer 3

Fossa ovalis

Question 4

What two components make up the interventricular septum?

Answer 4

Membranous and muscular

Question 5

What two walls make up the interatrial septum?

Answer 5

Septum primum, septum secundum

Question 6

Which of the two interatrial septae develop first?

Answer 6

Septum primum

Question 7

What forms the primitve heart tube?

Answer 7

Fused endocardial tubes

Question 8

From which germ layer does heart tissue arise?

Answer 8

Splanchnic mesoderm

Question 9

In the direction of blood flow, name the primitive heart tube sections?

Answer 9

Sinus Venosus, Atrium, Ventricle, Bulbus Cordis, Truncus Arteriosus, Aortic Roots

Question 10

In which direction does blood flow in the primitive heart tube?

Answer 10

Caudal–>cranial

Question 11

Describe the flow of blood through the primitive heart after looping?

Answer 11

Through common atria, atrioventricular canal, primitive L ventricle, interventricular foramen, primitive R ventricle, bulbus cordis, truncus arteriosus

Question 12

What forms the right atrium?

Answer 12

Most of the primitive atrium, a little bit of the sinus venosus (when it enlarges and incorporates it)

Question 13

What forms the left atrium?

Answer 13

Very little bit of prim. atrium, absorbs proximal parts of pulmonary veins.

Question 14

What happens to the sinus venosus?

Answer 14

Originally they are equal sized, then venous return favours RHS,

Question 15

What does fetal circulation bypass? And why?

Answer 15

Liver- otherwise all nutrients would be used up here.

Lungs- because they are behind in development so would become damaged due to blood flow.

Question 16

What does septation achieve?

Answer 16

Formation of interventricular septum, interatrial septum, also septation of ventricular outflow tract to form aorta & pulm. trunk

Question 17

Then do lots more on stages of different septations

Answer 17

?

Question 18

How does the foramen ovale close upon birth?

Answer 18

Upon first breath after birth, pressure in L atrium increases to above pressure in R atrium, TF septum primum pushes against septum secundum and fuses.

Question 19

What ‘holes’ form in the septum primum?

Answer 19

1st- ostium primum, 2nd- ostium secundum.

Question 20

Describe the direction of growth in ventricular septation

Answer 20

Muscular septum grows upwards towards endocardial cushion. Then membranous portion closes hole.

Question 21

Describe septation of ventricular outflow tract

Answer 21

Week 5- spiralled ridges form in walls of Truncus Arteriosus, these ridges then fuse by growing towards each other. They form contruncal ridges which splits it into aorta & pulm. trunk

Question 22

What results if septation of ventricular outflow trunk in truncus arteriosus fails?

Answer 22

Transposition of great vessels.

Question 23

How many aortic arches do we have in development?

Answer 23

5–> numbered 1, 2, 3, 4, 6 (NO FIVE!!!)

Question 24

Where is the recurrent laryngeal nerve found?

Answer 24

Hooked around the ductus arteriosus/ligamentum arteriosum