Deck 13: Development of the Heart

Question 1

Heart chamber specification is dependent on the loss,gain,or limited expression of several transcription factors.What pattern of expression supports specification and formation of the right ventricle?

A) Loss of expression of Tbx5 within the primary heart field
B) Loss of expression of Irx4 within the cranial portion of the primary heart field
C) Restricted expression of RALDH-2 to the cranial portion of primary heart field
D) Continued expression of Isl1 and Tbx1 within the secondary heart field

Answer 1

D

Question 2

Mutations in the Nkx2.5 gene can be found associated with what cardiovascular anomaly (anomalies)?

A) An aberrant cardiac conducting system
B) Atrial septal defects
C) Ventricular septal defects
D) Abnormal cardiac looping
E) All the above

Answer 2

E

Question 3

A newborn soon begins exhibiting signs of cyanosis.Using Doppler ultrasound,you find that the right ventricle is enlarged with evidence of reduced pulmonary blood flow,an overriding aorta,and a ventricular septal defect.What is the likely diagnosis?

A) Transposition of the great vessels
B) Tetralogy of Fallot
C) Persistent truncus arteriosus
D) Tricuspid valvular atresia
E) Dextrocardia

Answer 3

B

Question 4

A 46-year-old female exhibits signs of congestive heart failure.After an ultrasound and MRI were performed,right ventricular hypertrophy was observed.The only other accompanying defect was an atrial septal defect in the upper portion of the interatrial wall.What might be an etiology mechanism leading to the formation of this defect?

A) Neural crest cell migration into the heart was perturbed.
B) There was an incursion of the spina vestibuli into the interatrial wall.
C) Ostium primum was not closed by the atrioventricular septum.
D) Atrioventricular cushion tissue did not form.
E) Ostium secundum was abnormally large.

Question 5

What type of cardiac defect would you expect if the conotruncal ridges failed to spiral as they fuse and divide the outflow tract?

A) Tetralogy of Fallot
B) Persistent truncus arteriosus
C) Transposition of the great vessels
D) A low atrial septal defect
E) Persistent (patent) ductus arteriosus

Question 6

What part of the heart is derived from the left sinus horn?

A) Sinus venarum
B) Superior vena cava
C) Coronary sinus
D) Interatrial septum
E) Crista terminalis

Question 7

Why is the cardiogenic area limited to the lateral plate mesoderm?

A) Because Bmp released from the overlying ectoderm restricts Gata4 expression to lateral plate mesoderm.
B) Because Chordin released from the notochord limits Bmp signaling to the more lateral mesoderm.
C) Because Nkx2.5 expression is restricted to paraxial mesoderm.
D) Because Wnt signaling stimulates Bmp release from the overlying ectoderm.

Question 8

What process is thought to play a key role in the realignment of the atrioventricular canal with both right and left atrial and ventricular chambers before completion of cardiac septation?

A) Myocardialization
B) Intussusception
C) Trabeculation
D) Epithelial-to-mesenchymal transformation of the endocardium
E) Angiogenesis within the atrioventricular region

Question 9

When exerting herself,a 2-year-old female patient develops blue-colored lips and clubbed fingers,gasps for air,and breathes heavily.Prior to this age,the patient showed no signs of illness.Clinical tests reveal only pronounced right ventricular hypertrophy accompanied by evidence of pulmonary congestion.What is the most likely cause?

A) Patient has a ventricular septal defect.
B) Patient suffers from transposition of the great vessels.
C) Patient has tetralogy of Fallot.
D) Patient has aortic valvular atresia.
E) Patient has an abnormal atrioventricular node.

Question 10

A researcher places a slice of the developing heart tube into culture.In a series of experiments,different areas are labeled to tract cells.Which cells when labeled will be shown to be the primary progenitors for cushion cells within the atrioventricular septum?

A) Neural crest cells
B) Cells of the proepicardial organ
C) Myocardial cells
D) Endocardial cells