Cardiac conduction system development — Flashcards

Flashcard 1: In which week of embryogenesis does the heart begin to beat? _____

Answer: Week 4 (4 weeks = 4 heart chambers)

Flashcard 2: Ventricular septal defects usually occur in the _____ portion of the interventricular septum

Answer: membranous

Flashcard 3: The primary heart tube _____ to establish left-right polarity beginning in week 4 of gestation

Answer: loops

Flashcard 4: During heart development, the right horn of the sinus venosus is incorporated into the right atrium to form the smooth-walled portion known as the _____

Answer: Sinus venarum

Extra: The right atrium has two main parts with different embryological origins: - **Sinus venarum**: The smooth-walled posterior part derived from the **right horn of the sinus venosus**. - **Pectinate muscles**: The rough-walled anterior part derived from the **primitive atrium**. The **crista terminalis** is the internal ridge that separates these two parts (derived from the right venous valve).

Flashcard 5: The embryonic _____ gives rise to the AV and semilunar valves

Answer: endocardial cushion

Flashcard 6: During heart development, growth of the _____ separates the atria from the ventricles.

Answer: Endocardial cushions

Flashcard 7: The 6th aortic arch forms the _____ artery and _____.

Answer: pulmonary

Flashcard 8: The 4th aortic arch forms the _____ artery.

Answer: adult aortic arch and subclavian

Flashcard 9: aorticopulmonary septum

Answer: neural crest

Flashcard 10: Embryological origin of most cardiovascular structures

Answer: mesoderm