Heart Development Flashcards
which arch gives rise to the adult aorta?
left 4th arch
which arches are joined by the ductus arteriosus?
left 4th and left 6th
which arch is involved in PRAA?
right 4th arch
what is PRAA?
persistent right aortic arch; when the distal right 4th arch persists (instead of releasing from the dorsal aorta and supplying the right thoracic limb as the subclavian artery), creating a vascular ring (ligamentum arteriosum) around the esophagus that must be surgically opened for survival; will see the trachea pulled down like a sandbag is on top in radiographs, may lead to megaesopahgus trying to pass through that vascular ring
what is the ductus arteriosus?
prenatally shunts blood from pulmonary trunk to aorta, bypassing the lungs; should close at birth due to high O2 signal
what is the foramen ovale?
a hole between the left and right atria; another prenatal shunt to bypass the undeveloped lungs that should close at birth when blood is not pushing it open
prenatally, is pressure higher in the left or right side of the heart? why?
pressure is higher in right side of heart prenatally because the umbilical blood flow is to the right side
what is postnatal PDA? compare to a large, chronic PDA
postnatal: ductus arteriosus remains patent after birth, so direction of blood is still from left to right if not too large a hole, but left ventricle will become dilates and hypertrophied from the extra blood flowing through it; can fix at this stage
large, chronic: high resistance to blood flow in lungs (like prenatally), blood pressure is higher in right ventricle than left ventricle (like prenatal), and blood flows from right to left (like prenatal); dog will collapse in back legs during exercise; cannot fix at this stage because pulmonary vasculature is irreparably altered
what structures are the products of arterial transformation? (5)
- pulmonary trunk
- ligamentum arteriosum
- aorta
- braciocephalic trunk
- left subclavian artery
