Heart 1

Question 1

Truncus arteriosus gives rise to:

Answer 1

Ascending aorta and pulmonary trunk

Question 2

Bulbus cordis gives rise to:

Answer 2

Smooth parts of left and right ventricles

Question 3

Primitiv e atrium gives rise to:

Answer 3

Trabeculated part of left and right atria

Question 4

Primitive ventricle gives rise to:

Answer 4

Trabeculated part of left and right ventricles

Question 5

Left horn of sinus venosus gives rise to:

Answer 5

Coronary sinus

Question 6

Right horn of sinus venosus gives rise to:

Answer 6

Smooth part of right atrium

Question 7

Right common cardinal vein and right anterior cardinal vein gives rise to:

Answer 7

Superior Vena Cava (SVC)

Question 8

What week does the heart start to beat spontaneously?

Answer 8

week 4 of development

Question 9

Defect in left-right dynein can lead to ____________ as seen in _________ syndrome

Answer 9

dextrocardia, Kartagener syndrome

Question 10

Ventricular septal defect most commonly occurs in which septum?

Answer 10

Membranous

not aorticopulmonary septum, muscular ventricular septum

Question 11

Patent foramen ovale caused by?

Answer 11

caused by failure of septum primum and septum secundum to fuse after birth And form atrial septum.
(can result in venous thromboemboli)

Question 12

Conotruncal abnormalities

Answer 12

aka “outflow tract abnormalities”

• Transposition of great vessels
• Tetralogy of Fallot
• Persistent truncus arteriosis

Question 13

Aortic/pulmonary valve derived from?

Q

Answer 13

endocardial cushions of outflow tract

Question 14

Mitral/tricuspid valve derived from?

Answer 14

fused endocardial cushions of AV canal

Question 15

How does HbF have higher affinity for O2 than maternal hemoglobin HbA across the placenta?

Answer 15

• Binds 2,3-BPG poorly →Hb stabilized in R state → curve shifts left
• 20% ↑er Bohr effect also (pH ↑s as fetal blood passes placenta) = favors O2 affinity → curve shifts left
• Changes favor O2 transfer from maternal→ fetal circulation
  (Left shift favors oxygen loading/binding)

Question 16

At birth, when the infant takes a breath what happens that results in closure of the foramen ovale and ductus arteriosus?

Answer 16

” ↓ resistance in pulmonary vasculature (due to lung expansion)
↑ left atrial pressure (vs the right due to ↑ in pulmonary blood flow)
= closure of foramen ovale
↑ in O2 (from respiration)
↓ in prostaglandins (from placental separation)
= closure of ductus arteriosus”

Question 17

Which drug works by inhibiting the production of prostaglandins? Which fetal structure can it help close?

Answer 17

Indomethacin - helps close patent ductus arteriosus

Prostaglandins E1 and E2 kEEp PDA open

Question 18

Name their fetal-postnatal derivative!

• Allantois → urachus
• ductus arteriosus →
• ductus venosus →
• foramen ovale →
• Notocord →
• Umbilical arteries →
• Umbilical veins →

Answer 18

• AllaNtois → urachus → mediaN unbilical ligament
• ductus arteriosus → ligamentum arteriosum
• ductus venosus → ligamentum venosum
• foramen ovale → fossa ovalis
• Notocord → nucleus pulposus
• UmbiLical arteries → mediaL umbilical ligaments
• Umbilical veins → ligamentum teres hepatis (in falciform ligament)

Question 19

SA and AV nodes are usually supplied by what artery?

Answer 19

Right coronary artery (RCA)

Question 20

Posterior descending / interventricular artery (PDA)

• what % supplies right dominant circulation?
• what % supplies left dominant circulation?
• what % supplies co- dominant circulation?

Answer 20

• 85% with PDA arising from RCA (right coronary a)
• 8% with PDA arising from LCX (left circumflex coronary a)
• 7% with PDA arising from both LCX and RCA

Question 21

coronary artery occlusion most commonly occurs in which artery on the heart?

Answer 21

Left anterior descending artery (LAD)

Question 22

the most posterior part of the heart is which chamber?

- enlargement of this chamber can cause _______ and __________

Answer 22

Left Atrium
dysphagia (due to compression of esophagus)
or
hoarseness (due to compression of left recurrent laryngeal nerve, a branch of the vagus)

Question 23

Primitive pulmonary vein gives rise to:

Answer 23

smooth parts of left atrium