Heart, Heart Development & Fetal CIrculation Flashcards
Name the parts of the pericardial sac and their relationship to each other and to the pleural and pericardial cavities
parietal pericardium: around the heart
fibrous pericardium/c.t.
pericardial pleura: between the heart and the lungs; outermost layer of pericardial sac
what is the origin of the left and right coronary arteries
coronary arteries originate from ascending aorta
describe the cardiac skeleton and its function. name the species its usually found
fibrous tissue + fibrocartilage, occasionally bone in bovine
separates atria and great vessels from ventricles
prevents propagation of electrical activity from atria to ventricles except via AV bundle
firm anchoring site of valve leaflets
points of maximum intensity of the left AV valve, aortic valve, pulmonary valve and right AV valve in the horse, dog and ox
Left AV valve - low left intercostal space 5
Aortic valve - high left IC space 4
pulmonary valve - low left IC space 3
Right AV valve - low right IC space 4
outline the early development of the heart
- around 3-4 weeks 2 endocardial tubes fuse and become the endocardial/cardiac tube
- from caudal to cranial, the truncus arteriosus forms, then ventricle, then atrium then sinus venosus
- truncus arteriosus gives rise to aortic arches and sinus venosus role as pacemaker retained in SA node
- cardiac tube becomes the cardiac loop with 2 chambers after folding
describe the formation of the atrial septa
- endocardial cushions between atrium & ventricle grow inwards towards the center separating atrium from ventricle into two separate channels
- septum primum & foramen primum form
- septum secundum & foramen secundum form
- foramen ovale “flutter valve” forms to connect the two atria to bypass pulmonary circulation
describe the formation of the ventricular septa
- endocardial cushions still participate in partitioning by growing inwards towards the center, separating the atrium and ventricle
- interventricular septum forms of mostly muscle going from the apex towards endocardial cushions but a small interventricular foramen persists
- this last part of the interventricular septum is just below the semilunar valves where VSD most likely to occur
where are ventricular septal defects most likely to occur
the last part of the interventricular septum just below the semilunar valves because a small interventricular foramen persists
describe the formation of the truncus arteriosus
- endocardial cushions still participating in partitioning
- outgrowth of walls of truncus and endocardial cushions
- gives rise to the spiral septum that divides truncus into pulmonary trunk and aorta
Identify which embryonic arches give rise to main adult arteries
arches III –> common carotid aa.
left arch IV –> aortic arch
right arch IV –> right subclavian a.
left arch VI –> ductus arteriosus
Define “vascular ring anomaly.” Describe the most common vascular ring anomaly, persistent right aortic arch, and be able to describe its clinical significance
vascular ring anomaly: aortic arch anomalies
the most common one is the persistent right aortic arch
- left arch IV –> left subclavian a.
- right arch IV –> aortic arch
- right dorsal aorta becomes descending aorta
-left 6th arch continues to function as ductus arteriosus but after birth turns into ligamentum arteriosum that forms ring around esophagus constricing it
ventricular septal defect
abnormal opening between ventricles
atrial septal defect
abnormal opening of atrial septum
persistant truncus arteriosus
failure of spiral septum to form correctly
ectopia cordis/ectopic heart
heart fails to make it into the chest and resides in the neck
common AV canal
no separation between the 4 chambers
transposition of the great vessels
failure of right ventricle to become pulmonary trunk or left ventricle to become aorta
stenosis of valves
narrowing, inflexible valvular aperture
dysplasia of valves
short, thickened, valvular cusps
atresia of valves
absence of valves
tetralogy of fallot
abnormal partitioning of the outflow tracts where the spiral septum divides the outflow tract unequally resulting in…
1. stenosis of pulmonary trunk
2. dextra positioning
3. VSD
4. hypertrophy of right ventricle
what is the urachus
what is the connection between the urinary bladder and the umbilicus
what is the foramen ovale “flutter valve”?
what does it turn into in the adult?
how does this happen?
allows connection between atria so blood can bypass the lungs
Fossa Ovalis in the adult
increased pressure
what is the ductus arteriosus?
what does it turn into in the adult?
how does this happen?
connects the pulmonary trunk and aorta in the fetal heart
becomes Ligamentous Arteriosum in the adult
due to change in oxygen tension
what is the round ligament of the bladder a remnant of
umbilical aa.
what is the round ligament of the liver a remnant of
umbilical v.
what is the ductus venosus and how does it close?
blood from the GI tract and umbilical v. bypass the hepatic capillary bed to the caudal vena cava
closed due to change in oxygen tension
patent ductus arteriosus
failure of closure of ductus arteriosus
patent foramen ovale
failure of closure of the foramen ovale
portosystemic (portocaval) shunt
failure of closure of the ductus venosus; results in a mixture of portal blood to systemic
most common congenital heart defect in dogs
patent ductus arteriosus
