Cardiovascular/Respiratory development Flashcards
What germ layer does the heart form from and at what time?
The heart forms from mesoderm at around 18-19 days
What is the name of the ‘horseshoe’ shaped area that forms from the mesoderm?
Heart development
Cardiogenic plate
What kind of cells form the cardiogenic plate?
Formed from cardiac myoblasts and blood islands
What is the name of the structure that forms either side of the cardiogenic plate
endocardial tube
lined by endothelial cells
What do the endocardial tubes fuse with caudally?
Vitelline vessels
extra-embryonic vessels in the yolk sac
Where do the endocardial tubes fuse and what is this area called?
They fuse midway along their length, this forms the tubular heart or cardiac tube
What are the 5 distinct regions that the tubular heart becomes after growth and expansion
- 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
What is morphogenesis?
Cardiac looping (occurs around weeks 4-5)
What occurs during cardiac looping?
The right ventricle (bulbus cordis) is placed next to the left ventricle
What does the larger right sinus venousus become?
after cardiac looping
It becomes the right atrium
What is the name of the septum that divides the atria and ventricles
The cardiac cushions
What is the name of the septum that divides the atria
septum primum and secondum
What is the name of the septum that divides the ventricles?
Interventricular septum
What is the name of the septum that divides the ‘outflow’ tracts?
Aortico-pulmonary septum
What is formed after the two cardiac cushions extend and fuse?
cardiac cushions= cardiac mesenchymal tissue
occurs at the atrioventricular junction
They form the septum intermedium
separates the canal into left and right atrio-ventricular openings
Where does the primary septum grow from?
Grows from the dorsal wall
What is the name of the hole that the primary septum forms?
Primary foramen
What is the secondary hole in the primary septum called?
secondary foramen
What is the name of the boundary formed by the secondary septum?
Foramen ovale
What are the ventricles marked by internally?
the primordial
interventricular septum
a fold
What are the ventricles marked by externally?
interventricular sulcus
a groove
What does the truncus arteriosus divide to form?
Forms two outflow tracts
aortic and pulmonary
Where do the aortic and pulmonary valves form?
swellings of sub-endothelial mesenchymal tissue
What is vasculogenesis?
The formation of blood vessels from blood islands
What is angiogenesis?
The budding of new vessels from already existing vessels
How many aortic arches are formed?
Six
What does the third arch give rise to?
internal and common carotid arteries
What does the left 4th arch give rise to?
definitive aortic arch
What does the right fourth arch become
proximal part of right subclavian artery
What do the 6th aortic arches become?
pulmonary arteries
Where does the respiratory diverticulum arise from?
It arises from the foregut endoderm
What does the respiratory diverticulum go on to form?
- Epithelial lining of trachea
- Larynx
- Bronchi and alveoli
What do lung buds form?
The left and right principal bronchi
Where do the aortic and pulmonary valves form from?
swellings of sub-endothelial mesenchymal tissue
What are the vitelline veins?
they return poorly oxygenated blood from the yolk sac
What are umbilical veins?
They carry well-oxygenated blood from the primordial placenta
What are the common cardial veins?
They return poorly oxygenated blood from the body of the embryo
What are the 3 foetal shunts that allow blood to bypass?
Foramen ovale,
Ductus arteriosus
Ductus venosus
Where does the respiratory diverticulum arise from?
it arises from foregut endoderm
What are some of the events that occur around birth?
There is contraction of umbilical arteries and veins to prevent bleeding
Contraction of musculature and compression of the thorax
