9/1 Embryology of the heart Flashcards
what is the termonology of embriology that is different from med.
the cranial or superior is the anterior in embryo; the tail or caudal is posterior in embrio
why do we care about cardio development?
most common birht defects. the leading cause of infant morality.
what is one of the unique properites of circulation
it is always needed and the needs change constantly and must be adapted to the living being as it changes from a tube to two chamber to a four chamber
how is vasculogeniss accomplished
this is accomplished through the molecules FGF2 and VEGF and comes from a blood island (starts with mesodermal cells
how is angiogenesis accomplished
depends on VEGF and is the branching and elaboration of existing vesicles, and builds from what is already there.
what are blood islands?
angiogenic cell clusters (should be vasculogenic) they are where vessels come from
what is the significance of blood islands
they will give vessels and the heart
where are the blood islands located
in the embryonic disc (spanchinic nesoderm) ; the chorionic somatic mesoderm.. ; conentinc stalk somatic mesoderm; yolk sac
what is the layer of cells that contains the blood islands in a horse shoe shape?
the heart starts out as a horse shoe of blood islands near the top, and cranial to the head. this is the splanchinc mesoderm.
Describe how the primordial heart gets to the thorax region:
head fold: bring the heart primordial to the thorax
how do lateral body folds affect the heart development?
brings the paired heart primordia together at the midline where they fuse
how do we get a cental tube of heart at the ventral midline
at 22 days the endocardial tube folds in and fuses to make the tube in the middle with the endocardial inside then the cardiac jelly, then the myocardium on the outside
what are the layers of the heart?
endocardium; cardiac jelly; and the myocardium; epicardium;
endocardium
inner most endothelial layer and continuous to the endothelial lining of the vasulature
cardiac jelly
extrcellular matrix and gives rise to the valves
myocardium
outer muscular layer.
epicardium
outer most layer, derived from the cells that migrate in from the septum transversum and form the coronary arteriers, include the endothelial lining and smooth muscle.
where is the gut located in a cross section of the embrio
below the notochord and above the heart
where is the spanchnic mesoderm
it lines below the GI tract and arose from the lateral plate mesoderm that splits open to give the spanchnic mesoderm
what will lead to the orientation of the heart?
cardiac looping which is coordinated with the left right orientation of the rest of the body.
how does cardiac looping work?
the heart will make an s curve where the ventricle starts at the cranial and then twists around the antrium and will end in the caudle position.
where does the heart fuse into one tube
ventral midline
where do the antrium start in a sinble tube heart
the antrium starts at the bottom and then twists counterclockwise around to end up towards the top (this is looking ventral to the left, and dorsal to the right in a side-on view.
describe the orientation of the primitive tube heart
the RA and LA in a branch at the bottom of the heart, then the LV in the middle bottom, and the RV in the middle and the Outflow at the top (called the CT).
