block III: Development of cardiovascular system (conf 1)

Question 1

What is the major system to function in the embryo?

Answer 1

Cardiovascular system

Question 2

Where is the heart developed from?

Answer 2

1. splanchnic mesoderm
2. paraxial and lateral mesoderm
3. neural crest cells

Question 3

When does the heart start to function?

Answer 3

beginning of 4th week

Question 4

When does future heart and vascular system start to develop?

Answer 4

middle of 3rd week

Question 5

Why is the development of heart necessary during early embryonic period?

Answer 5

To meet embryonic demands for oxygen and nutrition (acquiring oxygen and nutrition from the maternal blood and disposing CO2 and waste products).

Question 6

What is the earliest sign of heart?

Answer 6

angioblastic cords

Question 7

What are angioblastic cords?

Answer 7

mesoderm agrupations bilateral, surge in 3rd week (paired endothelial strands)

Question 8

Where do angiogenic cords form?

Answer 8

form in mesoderm from inductive signals from underlying anterior endoderm (Vascular Endothelial Growth Factors = VEGFs)

Question 9

What does the angiogenic cords form?

Answer 9

Cords canalize to form heart tubes, which fuse to form the tubular heart late in the 3rd week

Question 10

How many tubes does the aorta have and how do they occur?

Answer 10

2 tubes (2 hearts); dorsal aorta. Tubes fuse due to lateral folds; aortas dont fuse, just the tubes.

Question 11

Where is the cardiogenic system located in the beginning?

Answer 11

in front of developing NS in development

Question 12

When does heart begin to beat?

Answer 12

22-23 days

Question 13

When does blood flow begin?

Answer 13

4th week

Question 14

What fuses?

Answer 14

the tubes; not the aortas, the aortas remain as 2

Question 15

Where do the aortas unite?

Answer 15

At the caudal end but they remain being 2

Question 16

Which are the 3 vein systems of a 4 week embryo?

Answer 16

-vitelline veins
-umbilical veins
-common cardinal veins

Question 17

What is the function of the vitelline veins?

Answer 17

return O2-poor blood from the yolk sac (comes from yolk sac, not from mom)

Question 18

What is the function of umbilical veins?

Answer 18

carry O2-rich blood from the future placenta.

Question 19

What is the function of common cardinal veins?

Answer 19

return O2-poor blood from the body of the embryo to the heart of the embryo.

Question 20

What is the primary site of hematopoiesis at 4 weeks old?

Answer 20

Yolk sac; This function is replaced by the liver starting around week 6 – 22 (eventually replaced by bone marrow).

Question 21

What causes 2 heart tubes to fuse?

Answer 21

lateral foldings

Question 22

What results in only one heart tube?

Answer 22

Lateral folding process making the cylindrical shape fuse the heart tubes

Question 23

What is analog to vena cava?

Answer 23

sinus venosus

Question 24

explain pathway of blood?

Answer 24

entra la sangre al seno venoso, luego pasa por el atrio primitivo, luego al ventriculo primitivo, luego pasa al bulbous cordis, luego pasa al tronco arterioso y luego al aortic sac. Del saco aortico sale a sus dos aortas dorsales

Question 25

explain the connection or anastomosis of the aortic sac with dorsal aorta

Answer 25

aortic sac connects to dorsal aorta by means of the pharyngeal arch arteries (5 arteries, la 5ta no existe)

Question 26

How many arches are there and name them

Answer 26

5; (1, 2, 3, 4, 6)

Question 27

How many pharyngeal arch arteries are present by 26 days?

Answer 27

1st to 3rd

Question 28

When does pharyngeal arteries 3, 4, 6 appear?

Answer 28

37 days; 1 and 2 disappear to turn into permanent structures

Question 29

What does the 1st pair of arch arteries turn to?

Answer 29

maxillary arteries (supply ears, teeth, and muscles of the eye and face); these aortic arches may also contribute to the formation of the external carotid arteries.

Question 30

What does the 2nd arch turn to?

Answer 30

Hyoidal/Stapedial artery; dorsal parts persist and form the stems of the stapedial arteries (these vessels run through the ring of the stapes which is a small bone in the middle ear).

Question 31

What does the 3rd arch turn to?

Answer 31

Common Carotid artery -> proximal part of internal carotid artery proximal parts form the common carotid arteries (supply structures in the head); distal parts join the dorsal aortae to form the internal carotid arteries (supply ears, orbit, brain and meninges).

Question 32

WHat other structure contributes to the formation of the internal carotid artery?

Answer 32

dorsal aorta

Question 33

What does the 4th arch turn to?

Answer 33

Right -> proximal part of R. Subclavian artery, Left -> Aortic Arch

Question 34

from what does the proximal and distal part of the 4th aortic arch develop?

Answer 34

proximal is from aortic sac and the distal part is derived from the left dorsal aorta

Question 35

where does the distal part of the right subclavian artery form from?

Answer 35

right dorsal aorta and right 7th intersegmental artery.

Question 36

Which arteries contribute to the right subclavian artery?

Answer 36

4th aortic arch, dorsal aorta, and right intersegmental artery 7th

Question 37

What does the 5th aortic arch turn to?

Answer 37

these become rudimentary vessels that soon degenerate or do not develop at all.

Question 38

What does the LEFT 6th aortic arch turn to?

Answer 38

The proximal part of the arch persists as the proximal part of the left pulmonary artery. The distal part passes from the left pulmonary artery to the dorsal aorta to form a shunt, the ductus arteriosus

Question 39

What does the RIGTH 6th aortic arch turn to?

Answer 39

- Proximal part persists as the proximal part of the right pulmonary artery. - The distal part degenerates.

Question 40

Where does left subclavian derive from?

Answer 40

The left subclavian artery is NOT derived from an aortic arch; it forms from the left 7th intersegmental artery. As development proceeds, differential growth shifts the origin of the left subclavian artery cranially; consequently, it comes to lie close to the origin of the left common carotid artery

Question 41

What does ductus arteriosus connect? and what does it do?

Answer 41

pulmonary artery with aorta; Bypass so that blood oxygenated from mom go thru embryo circulation; turns into the ligamentum arteriosum after birth

Question 42

Where does Recurrent Laryngeal Nerve come from?

Answer 42

ramification of vagus nerve

Question 43

Where does BOTH recurrent laryngeal nerve pass through at 6 weeks?

Answer 43

below arch 6th

Question 44

what happens to the right laryngeal nerve when distal portion of right arch 6 degenerates?

Answer 44

below arch 4, due to the 5th not being present

Question 45

where does left recurrent laryngeal nerve pass through after birth?

Answer 45

through ligamentum arteriosum

Question 46

where does right recurrent laryngeal nerve pass through after birth?

Answer 46

below right subclavian artery