Anatomy Lecture 19_Cardiovascular Embryology Flashcards
What does the foreman ovale do?
The Foramen ovale is a flap valve that shunts blood from the right atrium to the left atrium. The reason fo this is in a featus the lunds are not functioning thus blood does not need to travle to the lungs for oxygenation. Blood oxygenation happens at the plecenta and oxygenated blood returns through the inferior vena cava
What does the ductus arteriosus do
it shunts blood from the pulmonary artery into the arch of the aorta.
What causes the ductus arteriosus to close
there are special chemoreceptors that monitor O2 partial presure. Once the baby is breathing on its own the chemoreceptors trigger constriction and the ductus arterious closes off.
What is the ductus venosus
it is the shunt that brings oxygenated blood from the placenta into the inferior vena cava
What causes Atrial Septal Defect (ASD)
ASD is when the septum primum and septum segundum do not overlap. This results in a loss of efficency because foramen ovale never closes up so blood will bass from the left atrium to the right atrium during contraction
What happens if the interventricular foramen fails to close (ventricular septal defect or VSD)?
oxygenated blood would pass from the left ventrical into the right ventrical to be re oxygenated. This would likly be an acyanotic heart defect
What happens if the bulbar ridges do not spiral during division of the truncus
You get two closed loops of circulation (the systemic and pulmonary loops never cross over) This is called Transposition of the great vessels
What happens if the bulbar ridge does not fuse with the ventricular septum
It will be similar to VSD where blood passes from the aorta to the pulmonary trunk to be reoxygenated. This is called a “Persistent Truncus Arteriosus”
Describe the “Tetrolagy of Fallot”
Tetrology of Fallot is caused by a combination of several factors. First the bulbar ridges do not fuse with the ventricular septum. Typically this would cause blood to move from the left to the right. In Tetrolagy of Fallot the persistent truncus arteriosus is combined with Pulmonary artery stenosis (small pulmonary artery due to unequal division of the truncus) The smaller pulmonary artery basically acts as an orifice plate and pushes blood from the right to the left because of the increased head. This pushes most of the blood into systemic circulation and makes it hard to oxygenate blood. This causes right ventrical hypertrophy.
What does the 6th pharyngeal arch artery turn into
it becomes the pulmonary trunk, ductus arteriosus (which turns into the ligamentum ateriosum
What does the 4th pharyngeal arch artery turn into
part of the aortic arch and part of the subclavian artery.
What does the 3th pharyngeal arch artery turn into
The left and right common carotid arteries
