Cardiac Development 2 Flashcards
how are AV valves and papillary muscles formed
after septum intermedium is formed the mesenchymal tissue surrounding each AV orifice becomes fibrous and forms valves attached to muscular cords which then lose its muscular tissue and gain primitive traberculae to form papillary muscles
how are semi lunarvalves formed
endocardial cushion swells to form trunchal, bulbal and aorticopulmonary septae when partitioning is almost complete minor truncal swelling appears. they begin to hollow out on upper surface to form semi lunar valves
formation of conducting system
heart starts beating 21 days
pacemaker activity only in left caudal side
pacemaker activity then moves to sinous venous which then moves to form SAN, AVN and bundle of his
ventricle walls then differentiate into conducting cells
what are the 2 stages of blood vessel development
vasculogenesis- angioblasts differentiate into endothelial cells to form major blood vessels
angiogenesis- vessels form from other vessels
when and what do phraengeal arches develop into
week 4,5
strucutres of head and neck
what is the conducting system made of
specialised cardiac muscle
what are pharengeal arches made of
mesoderm core, external ectoderm layer, internal endoderm
pharengeal arches labelling
I,II,III,IV,VI craniocaudal sequence
supplied by aortic arches
what happens to pharengeal arches I,II
both destryed
what happens to pharengeal arch III
form common, external and proximal internal carotids
what happens to pharengeal arch IV
Left: forms aortic arch
right: forms subclavian artery
what happens to pharengeal arch VI
pulmonary arteries
vitelline arteries
carry blood from yolk sac to sinus venous
Umbilical arteries
carry oxygenated blood from placenta to embryo
cardinal veins
drains the embryo proper- the systemic venous system
