Cardiovascular/Respiratory development

Question 1

What germ layer does the heart form from and at what time?

Answer 1

The heart forms from mesoderm at around 18-19 days

Question 2

What is the name of the ‘horseshoe’ shaped area that forms from the mesoderm?

Heart development

Answer 2

Cardiogenic plate

Question 3

What kind of cells form the cardiogenic plate?

Answer 3

Formed from cardiac myoblasts and blood islands

Question 4

What is the name of the structure that forms either side of the cardiogenic plate

Answer 4

endocardial tube

lined by endothelial cells

Question 5

What do the endocardial tubes fuse with caudally?

Answer 5

Vitelline vessels

extra-embryonic vessels in the yolk sac

Question 6

Where do the endocardial tubes fuse and what is this area called?

Answer 6

They fuse midway along their length, this forms the tubular heart or cardiac tube

Question 7

What are the 5 distinct regions that the tubular heart becomes after growth and expansion

Answer 7

• Truncus arteriosus (aorta and pulmonary trunk)
• Bulbus cordis (right ventricle)
• Ventricle (left ventricle)
• Atrium (cranial portion of both left and right atria/ auricles)
• Sinus venosus (remains bifurcated-paired area where veins
  drain
  -Larger right sinus venosus and smaller left sinus venosus

Question 8

What is morphogenesis?

Answer 8

Cardiac looping (occurs around weeks 4-5)

Question 9

What occurs during cardiac looping?

Answer 9

The right ventricle (bulbus cordis) is placed next to the left ventricle

Question 10

What does the larger right sinus venousus become?

after cardiac looping

Answer 10

It becomes the right atrium

Question 11

What is the name of the septum that divides the atria and ventricles

Answer 11

The cardiac cushions

Question 12

What is the name of the septum that divides the atria

Answer 12

septum primum and secondum

Question 13

What is the name of the septum that divides the ventricles?

Answer 13

Interventricular septum

Question 14

What is the name of the septum that divides the ‘outflow’ tracts?

Answer 14

Aortico-pulmonary septum

Question 15

What is formed after the two cardiac cushions extend and fuse?

cardiac cushions= cardiac mesenchymal tissue

occurs at the atrioventricular junction

Answer 15

They form the septum intermedium

separates the canal into left and right atrio-ventricular openings

Question 16

Where does the primary septum grow from?

Answer 16

Grows from the dorsal wall

Question 17

What is the name of the hole that the primary septum forms?

Answer 17

Primary foramen

Question 18

What is the secondary hole in the primary septum called?

Answer 18

secondary foramen

Question 19

What is the name of the boundary formed by the secondary septum?

Answer 19

Foramen ovale

Question 20

What are the ventricles marked by internally?

Answer 20

the primordial
interventricular septum

a fold

Question 21

What are the ventricles marked by externally?

Answer 21

interventricular sulcus

a groove

Question 22

What does the truncus arteriosus divide to form?

Answer 22

Forms two outflow tracts

aortic and pulmonary

Question 23

Where do the aortic and pulmonary valves form?

Answer 23

swellings of sub-endothelial mesenchymal tissue

Question 24

What is vasculogenesis?

Answer 24

The formation of blood vessels from blood islands

Question 25

What is angiogenesis?

Answer 25

The budding of new vessels from already existing vessels

Question 26

How many aortic arches are formed?

Answer 26

Six

Question 27

What does the third arch give rise to?

Answer 27

internal and common carotid arteries

Question 28

What does the left 4th arch give rise to?

Answer 28

definitive aortic arch

Question 29

What does the right fourth arch become

Answer 29

proximal part of right subclavian artery

Question 30

What do the 6th aortic arches become?

Answer 30

pulmonary arteries

Question 31

Where does the respiratory diverticulum arise from?

Answer 31

It arises from the foregut endoderm

Question 32

What does the respiratory diverticulum go on to form?

Answer 32

• Epithelial lining of trachea
• Larynx
• Bronchi and alveoli

Question 33

What do lung buds form?

Answer 33

The left and right principal bronchi

Question 34

Where do the aortic and pulmonary valves form from?

Answer 34

swellings of sub-endothelial mesenchymal tissue

Question 35

What are the vitelline veins?

Answer 35

they return poorly oxygenated blood from the yolk sac

Question 36

What are umbilical veins?

Answer 36

They carry well-oxygenated blood from the primordial placenta

Question 37

What are the common cardial veins?

Answer 37

They return poorly oxygenated blood from the body of the embryo

Question 38

What are the 3 foetal shunts that allow blood to bypass?

Answer 38

Foramen ovale,
Ductus arteriosus
Ductus venosus

Question 39

Where does the respiratory diverticulum arise from?

Answer 39

it arises from foregut endoderm

Question 40

What are some of the events that occur around birth?

Answer 40

There is contraction of umbilical arteries and veins to prevent bleeding
Contraction of musculature and compression of the thorax