Section 19.5: Development of the Heart - Questions

At what day does the human heart begin beating and pumping blood?

a) Day 18

b) Day 21 or 22

c) Day 25

d) Day 28

b) Day 21 or 22

Which embryonic tissue gives rise to the heart?

a) Ectoderm

b) Mesoderm

c) Endoderm

d) Neural crest

b) Mesoderm

What does the truncus arteriosus develop into in the adult heart?

a) Right ventricle

b) Left ventricle

c) Ascending aorta and pulmonary trunk

d) Coronary sinus

c) Ascending aorta and pulmonary trunk

Which region of the primitive heart tube becomes the right ventricle?

a) Truncus arteriosus

b) Bulbus cordis

c) Primitive ventricle

d) Sinus venosus

b) Bulbus cordis

During which days does the primitive heart tube begin to fold into an S shape?

a) Days 18-19

b) Days 21-22

c) Days 23-28

d) Days 29-35

c) Days 23-28

The heart forms from the embryonic tissue called ___ around 18 to 19 days after fertilization.

mesoderm

The primitive heart tube forms five distinct regions: truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and ___.

sinus venosus

Describe the process of heart tube folding and its significance in heart development.

The primitive heart tube elongates and folds within the pericardium, forming an S shape between days 23 and 28. This folding aligns the chambers and major vessels into a configuration similar to the adult heart, which is crucial for proper heart function.

What are the roles of the septa and valves in heart development?

The septa partition the atria and ventricles, while the valves ensure unidirectional blood flow. The interatrial, interventricular, and atrioventricular septa complete by the fifth week, and the atrioventricular and semilunar valves form between weeks five and nine.