Embryology

Question 1

List 5 parts of endocardial tube:

Answer 1

1- Sinus Venous
2-Primordial Atrium
3-Primirdial Ventricle
4-Bulbus Cordis
5-Aortic Sac

Question 2

Describe endocardial tube

Answer 2

endocardial tube is a space; surrounded by cardiac kelly; will develop into myocardium

Question 3

Blebs appear in endocardial tube that will move into cardiac jelly and carve out which structures:

Answer 3

valves- papillary muscles- chords tendinea

Also, Inter ventricular septum appears

Question 4

Partitioning of common AV canal into:

Answer 4

Right and Left AV canals

Question 5

Division of Sinus Venosus and PA into:

Answer 5

Right and left atria

Question 6

Separation PV and BC into:

Answer 6

Right and left ventricles

Question 7

how are proximal aorta and PT formed?

Answer 7

Spiral partitioning of the Conus cordis and truncus arteriosus

Question 8

Describe what happens in week 4:

Answer 8

Anterior and posterior endocardial cushions start to develop and grow and approach each other

Also, lateral endocardial cushions also appear and grow

Question 9

What happens when the ventral and dorsal endocardial cushions meet?

Answer 9

they separate the common AV canal into Right and left AV canal; (they will become the AV orifices)

Question 10

What forms the membranous portion of the IV septum?

Answer 10

extension from the endocardial cushion. (IV septum grows between R & L AV canals but does not touch endocardial cushions hence the gap is filled with extension from the endocardial cushion)

Question 11

What happens when IV septum is formed?

Answer 11

Separates the PV which will become the Left ventricle

and the proximal part of the BC will become the right ventricle

Question 12

Where does septum premium forms?

Answer 12

Roof of the Primordial Atrium and grows inferiorly towards endocardial cushion to form interatrial septum

Question 13

What happens before septum premium completely builds the IA septum?

Answer 13

A second hole forms high up on the septum premium called: Ostium secundum

Question 14

Whats the new septum that grows after septum premium?

Answer 14

Septum Secundum grows down the roof on the RIGHT side of septum premium

Question 15

What happens when IA septum is formed?

Answer 15

PA divides into right and left atria

Question 16

What does the Left Atrium and Right atrium receive?

Answer 16

Left atrium receives Pulmonary veins & the right atrium receives Sinus Venosus

Question 17

What will become of Sinus Venosus?

Answer 17

will differentiate into Superior and Inferior Vena Cava

Question 18

In embryo Sinus Venous becomes what in adults?

Answer 18

Right atrium- Vena Cava (esp SVC)- Coronary Sinus

Question 19

In embryo Primordial Atria (PA) becomes what in adults?

Answer 19

Right & Left auricles- left atrium

Question 20

In embryo Primordial Ventricle becomes what in adults?

Answer 20

Left Ventricle

Question 21

In embryo Bulbus Cordis becomes what in adults?

Answer 21

Proximal part: Right Ventricle;

Conus Cordis: Infundibulum (RV) and Aortic Vestibule (LV); Truncus Arteriosus: Proximal Aorta and PT

Question 22

In embryo the aortic sac becomes what in adults?

Answer 22

Aorta and Pulmonary artery

Question 23

What does the 1st aortic arch lead to?

Answer 23

Dorsal aorta

Question 24

What are the intersegmental arteries and what do they supply?

Answer 24

branches from the left, right, and common dorsal aorta;

they supply the surrounding tissues

Question 25

where does the 6th aortic arch reach out?

Answer 25

6th arch appears, reaching out the aorta a little inferiorly, close to the lung buds

Question 26

What does the 7th intersegmental artery supply?

Answer 26

7th intersegmental artery starts to grow outwards to supply the limb bud

Question 27

What does the 3rd arch form?

Answer 27

forms the internal carotid artery, growing out of the common carotid artery

Question 28

What will become of the 6th aortic arch?

Answer 28

6th arch sends little branches to the developing lung buds which will become the pulmonary arteries

Question 29

what happens to the intersegmental arteries?

Answer 29

1-6 intersegmental arteries degenerate while 7th intersegmental artery becomes the subclavian artery

Question 30

What starts to appear between the first 7 intersegmental arteries?

Answer 30

a bridge-like vessel appears and starts to grow cranially towards the base of the brain

Question 31

What happens to the elongating bridge-like artery?

Answer 31

becomes the vertebral artery, joins its counterpart, becomes basilar artery, and forms circle of willis with ICA

Question 32

What happens to the right and left dorsal aorta?

Answer 32

right dorsal aorta starts to degenerate while the left dorsal aorta remains intact and connected with the descending aorta

Question 33

What becomes of the Truncus Arteriosus?

Answer 33

Proximal part of the ascending aorta & Pulmonary Trunk

Question 34

What becomes of the aortic sac?

Answer 34

Aorta (ascending aorta, aortic arch) and proximal brachiocephalic trunk

Question 35

What becomes of the 3rd arch?

Answer 35

Right and Left Common Carotid artery and ICA

Question 36

What becomes of the 4th arch?

Answer 36

Right: Right subclavian artery (partly)
Left: aortic arch (partly)

Question 37

What becomes of the 6th arch?

Answer 37

Right: Right pulmonary artery- right vertebral artery-right internal thoracic artery

Left: Left pulmonary artery- Ductus arteriosus- Left vertebral artery- left internal thoracic artery

Question 38

What becomes of the 7th intersegmental artery?

Answer 38

Right: Right subclavian artery
Left: Left subclavian artery

Question 39

What becomes of the dorsal aorta?

Answer 39

Right: Right Subclavian artery (partly)

Left: Aortic arch (partly)- Descending aorta