Development of Primitive Cardio System + Fetal Circulation

Question 1

What are the 2 main processes in CV system formation?

How do they differ?

Answer 1

1. Vasculogenesis - vessel formation from mesoderm cells
2. Angiogenesis - vessels form from budding of pre-existing vessels

Question 2

What are the steps of the general process for the initial formation of the embryonic cardiovascular system?

Answer 2

A B C F V A

All Boston Cabbies Find Vagina Appealing

• begin at end of 3rd week

1. Angioblast Differentiation - mesenchymal cells > angioblasts
2. Blood Island Formation - angioblasts aggregate > blood islands
3. Cavities - intercellular clefts combine to form cavities in islands
4. Flattening - angioblasts flatten to form endothelium
5. Vasuculogenesis - endothelium-lined cavities fuse to form vessels
6. Angiogenesis - endothelial budding > new vessels sprout from old

Question 3

What are the cells which blood cells develop from?

Answer 3

hemangioblasts

Question 4

What necessitates the early development of embryonic CV system?

Answer 4

there is little yolk in the oocyte so…

blood vessesl and uteroplacental circulation is necessary

Question 5

Where do the heart and large vessels form from?

Where is it?

Answer 5

Cardiogenic Area

at cranial end of embryonic disc

Question 6

What is the process of heart formation?

Answer 6

ET M TH S

“ET Made THe Sun”

1. Endocardial Tubes form via angioblasts from lateral plate meso
2. Merging of endocardial tubes
3. Tubular Heart is formed
4. Septation splits heart into 4 chambers

Question 7

What is part of the embryonic heart eventually becomes the aorta and pulmonary trunk?

Answer 7

Truncus Arteriosus

Question 8

What two structures give rise to the ventricles?

Answer 8

Bulbus Cordis - bulb shaped structure on top

Primitive Ventricle - structure below

Question 9

What structure lies at the bottom of the embryonic heart?

Answer 9

Sinus Venosus

• between two veins which become the venae cavae

Question 10

When does the blood begin to circulate via the heartbeat?

Answer 10

day 21/22

Question 11

Describe chorionic villi development.

Answer 11

B MC C D T CTS SB

1. Branching - primary chorionic villi branch
2. Mesenchymal Core - branched villi gain mesenchymal core
3. Covering - these 2dary villi cover entire chorion surface
4. Differentiaton - mesenchymal cells diff. into capillaries and blood cells
5. Tertiary - once vessels are visible they are tertiary villi
6. Cytotrophoblastic Shell - forms from extension thru syncytio-
7. Stem + Branch - stem villi extend thru CT shell, branch villi stick off

Question 12

What 5 main things are unique about fetal circulation?

Answer 12

1. Umbilical Vein carries oxygenated blood to fetus
2. **Ductus Venosus **shunts blood from liver to IVC
3. Foramen Ovale shunts blood from right to left atrium
4. Umbilical Arteries carry deoxygenated blood away from fetus
5. **Ductus Arterious **shunts blood out of pulmonary arteries to bypass the non-functioning lungs