Development Flashcards
What is vasculogenesis?
Development of new blood vessels
What is angiogenesis?
Process where existing blood vessels length or branch by sprouting, continues postnatally
Where does blood and vessel development first begin before development begins in the embryo?
Extra-embryonically aka from the mother
What are ‘blood islands’?
Clusters of splanchnic mesoderm that lines the yolk sac
(T/F) Hemangioblasts are lineage committed
True
(T/F) Fetal hemoglobin is structurally the same as adult hemoglobin.
False
What do the angiogenic cell clusters in the cardiogenic plate give rise to?
Endocardial tubes
The cephalocaudal fold brings the heart dorsal or ventral to the pericardium?
Dorsal
Listed below are the different linings/layers of the developing heart, give the structure they become postnatally.
- Endothelial lining →
- Myoepicardial layer →
- Visceral layer lining the pericardial cavity →
- Endothelial lining → (Endocardium) - - - Myoepicardial layer → (Myocardium)
- Visceral layer lining the pericardial cavity → (Epicardium)
Why does the primitive heart go from a long tubular structure to a ‘S-shaped’ bent structure?
It is outgrowing the pericardial cavity
*What structures extend towards each other and fuse to create the left and right atrioventricular openings?
The endocardial ‘cushions’
What is the resulting anatomical structure of trabeculation (the process in which the heart grows without encroaching on the the luminal space of the ventricles, a balance between thickening of the heart walls and apoptosis of the endocardium) in the adult heart?
Trabeculae carneae
Why is pressure high in the right ventricle of the fetal heart?
Fetal lungs are not yet inflated
What is the name for the foramen that persists in the second atrial divider in the fetal heart?
Foramen ovale
What structures fuse in a twisting pattern to separate the common outflow tract of the fetal ventricles into two separate tracts, each serving one ventricle?
Trucoconal ridges
What does the 4th arches of the fetal aorta form?
Right → right subclavian; left → aortic arch
What does the 6th arches of the fetal aorta form?
Right → proximal pulmonary artery; left → ductus arteriosus
(T/F) Developmental cardiac anomalies are one the most common congenital defects faced by a general practitioner.
True
Is the incidence of congenital cardiac anomalies higher or lower in purebred dogs?
Higher
What does cyanosis result from?
Inadequate oxygenation of blood
What is the term for excessive fibrous tissue in the ventricular wall just preceding the aortic valve, the most common congenital cause for aortic stenosis?
Subvalvular aortic stenosis
What does the narrowing of the left ventricular outflow tract (aortic stenosis) cause?
Left ventricular overload → ventricular hypertrophy
The narrowing of the pulmonary outflow tract, pulmonic stenosis, is usually caused by malformation of what?
Valves, valvular malformation
Faulty development of what prenatal structure produces left/right AV valve leaflets that are too short?
Endocardial cushions
Ventricular septal defects are reported in all species but is the most common cardiac malformation in small or large animals?
Large
Which of the forms of ventricular septal defects are more common?
Membranous
Besides a defective atrial septum, what else can cause an atrial septal defect?
Failure of foramen ovale to close
In which atrium does the pressure need to be higher to keep the foramen ovale closed postnatally if it does not fuse properly?
Left atrium
What malformation is the most common among the cyanotic malformations?
Tetralogy of fallot
What are the four defects that make up the tetralogy of fallot?
Pulmonic stenosis, high ventricular septal defect, overriding aorta, and right ventricular hypertrophy
(T/F) The tetralogy of fallot results from a single malformation.
True
What is the most common cardiovascular anomaly in dogs, particularly poodles, collies and GSDs?
Patent ductus arteriosus
What adult structure is formed by the closing off of the ductus arteriosus by muscular action within hours after birth?
Ligamentum arteriosum
Why is the murmur associated with a patent ductus arteriosus constant?
Blood moves through the ductus at all phases of the cardiac cycle
What results from a persistent ductus venosus?
Portosystemic shunt
Vascular ring anomalies are related to the incorrect development of what fetal structures?
Aortic arches
Why do clinical signs associated with a persistent right aortic arch (in which the esophagus and trachea get trapped near the heart base between the right arch and the ligamentum arteriosum) tend not to show until weaning?
Milk easily slides past the pinch, not so much solid food
In which species does ectopic heart malformations occur more often?
Cattle
(T/F) If no other malformations occur with an ectopic heart, it is compatible with life.
True
(T/F) The fetal lungs and liver are non-functional
True
What four adult organs does the placenta function as for the fetus?
Lungs, liver, kidneys, and intestines
What does the ductus venosus bypass?
The liver
What two structures are used to bypass the lungs in a fetus?
Foramen ovale and ductus arteriosus
What vessels does the fetal aorta give which carry deoxygenated, nutrient depleted, waste-laden blood to the placenta for exchange?
Umbilical arteries
What is the remnant of the umbilical vein in adults?
Round ligament of the liver
What are the remnants of the umbilical arteries in adults?
Round ligaments of the bladder
What is the remnant of the ductus venosus in adults?
Ligamentum venosum
In which species does the ductus venosus disappear during the latter part of gestation?
Neigh and oink
What is the remnant of the foramen ovale?
Fossa ovalis
Right to left shunting PDAs are typically secondary to what?
Pulmonary hypertension
Which of the PDA shunts, R → L or L → R, is non-cyanotic?
L → R
The cyanosis resulting from R → L shunts is typically seen in the caudal or cranial parts of the body?
Caudal
