Development

Question 1

What is vasculogenesis?

Answer 1

Development of new blood vessels

Question 2

What is angiogenesis?

Answer 2

Process where existing blood vessels length or branch by sprouting, continues postnatally

Question 3

Where does blood and vessel development first begin before development begins in the embryo?

Answer 3

Extra-embryonically aka from the mother

Question 4

What are ‘blood islands’?

Answer 4

Clusters of splanchnic mesoderm that lines the yolk sac

Question 5

(T/F) Hemangioblasts are lineage committed

Answer 5

True

Question 6

(T/F) Fetal hemoglobin is structurally the same as adult hemoglobin.

Answer 6

False

Question 7

What do the angiogenic cell clusters in the cardiogenic plate give rise to?

Answer 7

Endocardial tubes

Question 8

The cephalocaudal fold brings the heart dorsal or ventral to the pericardium?

Answer 8

Dorsal

Question 9

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 →

Answer 9

• Endothelial lining → (Endocardium) - - - Myoepicardial layer → (Myocardium)
• Visceral layer lining the pericardial cavity → (Epicardium)

Question 10

Why does the primitive heart go from a long tubular structure to a ‘S-shaped’ bent structure?

Answer 10

It is outgrowing the pericardial cavity

Question 11

*What structures extend towards each other and fuse to create the left and right atrioventricular openings?

Answer 11

The endocardial ‘cushions’

Question 12

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?

Answer 12

Trabeculae carneae

Question 13

Why is pressure high in the right ventricle of the fetal heart?

Answer 13

Fetal lungs are not yet inflated

Question 14

What is the name for the foramen that persists in the second atrial divider in the fetal heart?

Answer 14

Foramen ovale

Question 15

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?

Answer 15

Trucoconal ridges

Question 16

What does the 4th arches of the fetal aorta form?

Answer 16

Right → right subclavian; left → aortic arch

Question 17

What does the 6th arches of the fetal aorta form?

Answer 17

Right → proximal pulmonary artery; left → ductus arteriosus

Question 18

(T/F) Developmental cardiac anomalies are one the most common congenital defects faced by a general practitioner.

Answer 18

True

Question 19

Is the incidence of congenital cardiac anomalies higher or lower in purebred dogs?

Answer 19

Higher

Question 20

What does cyanosis result from?

Answer 20

Inadequate oxygenation of blood

Question 21

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?

Answer 21

Subvalvular aortic stenosis

Question 22

What does the narrowing of the left ventricular outflow tract (aortic stenosis) cause?

Answer 22

Left ventricular overload → ventricular hypertrophy

Question 23

The narrowing of the pulmonary outflow tract, pulmonic stenosis, is usually caused by malformation of what?

Answer 23

Valves, valvular malformation

Question 24

Faulty development of what prenatal structure produces left/right AV valve leaflets that are too short?

Answer 24

Endocardial cushions

Question 25

Ventricular septal defects are reported in all species but is the most common cardiac malformation in small or large animals?

Answer 25

Large

Question 26

Which of the forms of ventricular septal defects are more common?

Answer 26

Membranous

Question 27

Besides a defective atrial septum, what else can cause an atrial septal defect?

Answer 27

Failure of foramen ovale to close

Question 28

In which atrium does the pressure need to be higher to keep the foramen ovale closed postnatally if it does not fuse properly?

Answer 28

Left atrium

Question 29

What malformation is the most common among the cyanotic malformations?

Answer 29

Tetralogy of fallot

Question 30

What are the four defects that make up the tetralogy of fallot?

Answer 30

Pulmonic stenosis, high ventricular septal defect, overriding aorta, and right ventricular hypertrophy

Question 31

(T/F) The tetralogy of fallot results from a single malformation.

Answer 31

True

Question 32

What is the most common cardiovascular anomaly in dogs, particularly poodles, collies and GSDs?

Answer 32

Patent ductus arteriosus

Question 33

What adult structure is formed by the closing off of the ductus arteriosus by muscular action within hours after birth?

Answer 33

Ligamentum arteriosum

Question 34

Why is the murmur associated with a patent ductus arteriosus constant?

Answer 34

Blood moves through the ductus at all phases of the cardiac cycle

Question 35

What results from a persistent ductus venosus?

Answer 35

Portosystemic shunt

Question 36

Vascular ring anomalies are related to the incorrect development of what fetal structures?

Answer 36

Aortic arches

Question 37

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?

Answer 37

Milk easily slides past the pinch, not so much solid food

Question 38

In which species does ectopic heart malformations occur more often?

Answer 38

Cattle

Question 39

(T/F) If no other malformations occur with an ectopic heart, it is compatible with life.

Answer 39

True

Question 40

(T/F) The fetal lungs and liver are non-functional

Answer 40

True

Question 41

What four adult organs does the placenta function as for the fetus?

Answer 41

Lungs, liver, kidneys, and intestines

Question 42

What does the ductus venosus bypass?

Answer 42

The liver

Question 43

What two structures are used to bypass the lungs in a fetus?

Answer 43

Foramen ovale and ductus arteriosus

Question 44

What vessels does the fetal aorta give which carry deoxygenated, nutrient depleted, waste-laden blood to the placenta for exchange?

Answer 44

Umbilical arteries

Question 45

What is the remnant of the umbilical vein in adults?

Answer 45

Round ligament of the liver

Question 46

What are the remnants of the umbilical arteries in adults?

Answer 46

Round ligaments of the bladder

Question 47

What is the remnant of the ductus venosus in adults?

Answer 47

Ligamentum venosum

Question 48

In which species does the ductus venosus disappear during the latter part of gestation?

Answer 48

Neigh and oink

Question 49

What is the remnant of the foramen ovale?

Answer 49

Fossa ovalis

Question 50

Right to left shunting PDAs are typically secondary to what?

Answer 50

Pulmonary hypertension

Question 51

Which of the PDA shunts, R → L or L → R, is non-cyanotic?

Answer 51

L → R

Question 52

The cyanosis resulting from R → L shunts is typically seen in the caudal or cranial parts of the body?

Answer 52

Caudal