Cardiovascular System I - Development of the Heart

Vocabulary practice flashcards covering early cardiac embryology, heart tube morphogenesis, cardiac looping, septation, valve formation, and associated clinical correlates.

Primary Heart Field (PHF)

A horseshoe-shaped region of progenitor cardiac cells located in the splanchnic layer of lateral plate mesoderm formed around days 16 to 18, giving rise to the atria, left ventricle, and part of the right ventricle.

Secondary Heart Field (SHF)

A heart progenitor cell population developing around days 20 to 21 situated ventral to the posterior pharynx that provides cells to lengthen the outflow tract (conus cordis and truncus arteriosus) and form part of the right ventricle.

Cardiac Looping

The morphogenetic process occurring between days 22 and 25 where the elongating primitive heart tube bends ventrally and caudally to the right at its cranial end, and dorsally and cranially to the left at its caudal end.

Septum Primum

A crest-like tissue ingrowth originating from the dorsal wall of the common atrium that grows toward the developing endocardial cushions during interatrial septation.

Ostium Primum

The initial temporary opening located between the lower edge of the septum primum and the endocardial cushions, which disappears upon fusion of the septum primum with the cushions.

Ostium Secundum

An opening formed by programmed cell death in the upper region of the septum primum prior to complete closure of the ostium primum, maintaining right-to-left atrial blood flow in fetal circulation.

Septum Secundum

A thick muscular fold that grows adjacent to the septum primum and overlaps the ostium secundum, forming the boundary of the foramen ovale.

Foramen Ovale

A one-way opening created by the overlapping of ostium secundum by septum secundum, guarded on its left side by a valve flap derived from septum primum to permit right-to-left atrial shunting.

Interventricular Septum

The cardiac partition dividing the ventricles, formed by the fusion of a muscular ingrowth from the inferior wall of the common ventricle with a membranous ingrowth from the septum intermedium.

Endocardial Cushions

Mesenchymal tissue swellings located in the atrioventricular canal that fuse between days 27 and 37 to divide the single AV canal into right and left orifices.

Aorticopulmonary Septum

A spiral septum formed in the cardiac outflow tract by the fusion of opposing conotruncal swellings, partitioning the truncus arteriosus into the ascending aorta and pulmonary trunk.

Semilunar Valves

Valves developed at the bases of the aorta and pulmonary artery from three endothelial-covered swellings that undergo upper surface excavation after aorticopulmonary septation.

Dextrocardia

A congenital condition in which the heart is positioned in the right thoracic cavity instead of its normal location in the left chest.

Tetralogy of Fallot

A cyanotic congenital heart malformation characterized by a stenotic pulmonary valve, ventricular septal defect, overriding aorta, and right ventricular muscular hypertrophy.

Ectopia Cordis

A congenital defect characterized by the complete or partial displacement of the heart outside the thoracic cavity wall.