Embryology - Normal Development of the Heart

70 flashcards covering key concepts in embryology of the heart, including circulation, fetal structures, septation, and postnatal changes.

What are the three circulations described in the lecture?

Systemic circulation, vitelline circulation, and placental circulation.

Name the fetal shunts that bypass the liver and lungs in fetal circulation.

Ductus venosus, foramen ovale, and ductus arteriosus.

Which vessel carries oxygenated blood from the placenta to the fetus?

Umbilical vein.

What does the ductus venosus bypass in fetal circulation?

The liver by shunting umbilical venous blood to the inferior vena cava.

Where does blood pass from the right atrium to the left atrium in the fetus?

Through the foramen ovale.

What shunt connects the pulmonary trunk to the aorta in fetal life?

Ductus arteriosus.

Which embryonic structure forms the coronary sinus?

The left horn of the sinus venosus (with contributions from left cardinal veins).

Which embryonic structure forms the smooth-walled part of the right atrium?

Right horn of the sinus venosus (sinus venarum).

What forms the atrioventricular septum during heart development?

Endocardial cushions.

Name the septa involved in atrial septation.

Septum primum and septum secundum.

What are the two components of the interventricular septum?

Muscular portion and membranous portion.

Which cells form the aortico-pulmonary (conotruncal) septum?

Neural crest cells.

What embryonic structures contribute to the outflow tracts of the heart?

Bulbus cordis and truncus arteriosus.

What does the truncus arteriosus divide into during development?

The aorta and the pulmonary trunk."

Which structure largely becomes the aorta and pulmonary trunk after development?

The truncus arteriosus (via the aortico-pulmonary septum).

Which embryonic structure becomes the conus arteriosus in the definitive heart?

Bulbus cordis.

What becomes the ligamentum arteriosum after birth?

Ductus arteriosus.

What becomes the ligamentum venosum after birth?

Ductus venosus.

What becomes the round ligament of the liver (ligamentum teres) after birth?

Left umbilical vein.

What becomes the medial umbilical ligaments after birth?

Umbilical arteries.

Which veins constitute the vitelline circulation in the embryo?

Vitelline veins and arteries (yolk sac circulation).

Where is the site of maternal blood in the placenta?

Intervillous space.

Which vessels drain the yolk sac to the primitive gut in early development?

Vitelline veins.

Which vessels contribute to the portal venous system in the embryo?

Vitelline veins forming the portal vein and hepatic sinusoids.

What is the role of the placenta in fetal circulation?

Site of exchange between maternal and fetal blood; maternal blood flows through intervillous space around chorionic villi.

Which vessels form the portal vein in the fetus?

Vitelline veins contribute to the portal system (portal vein).

What is the fate of the left horn of the sinus venosus?

Becomes the coronary sinus.

What is the fate of the right horn of the sinus venosus?

Becomes part of the smooth-walled right atrium (sinus venarum).

Where does the coronary sinus drain in the adult heart?

Into the right atrium.

Which embryonic vein contributes to the coronary sinus along with the left horn of the sinus venosus?

Left anterior cardinal vein and left common cardinal vein.

What happens to the umbilical veins and arteries after birth?

Umbilical veins become the round ligament of the liver (ligamentum teres); umbilical arteries become the medial umbilical ligaments.

Which arteries supply the stomach and spleen in the embryo?

Celiac trunk.

Which arteries supply the midgut in the embryo?

Superior mesenteric artery.

Which arteries supply the hindgut in the embryo?

Inferior mesenteric artery.

What is the relationship between the portal and caval veins in the embryo?

Vitelline and portal venous system versus caval (systemic) venous return; portal system drains GI tract to liver.

What is the difference between fetal and neonatal circulation regarding shunts?

Fetal life uses shunts (foramen ovale, ductus arteriosus, ductus venosus) to bypass lungs and liver; after birth these close to separate circulations.

Which vessels form the fetal pulmonary arteries and ducts?

Truncus arteriosus and the conotruncal septation (neural crest contribution).

What are the major shunts that cease to function after birth?

Foramen ovale, ductus arteriosus, and ductus venosus.

What is the fetal circulation diagram element labeled as ‘Bulbus cordis’?

Contributes to the right ventricle outflow tract and parts of the left ventricle inflow region.

What is the aortic arches’ relevance to heart development?

Pharyngeal (aortic) arches 1–6 contribute to major vessels; the 4th arch contributes to the aortic arch; the 6th arch contributes to pulmonary arteries and ductus arteriosus.

What cells migrate to form the aortico-pulmonary septum?

Neural crest cells.

What are the primary components of the interventricular foramen’s formation?

Muscular septum, membranous septum, and endocardial cushions contribute to ventricular septation.

What is the fate of the ventricular outflow tract in development?

Outflow tract forms parts of the aorta and pulmonary trunk after conotruncal (aortico-pulmonary) septation.

What structure forms the fossa ovalis after birth?

The foramen ovale seals; its site becomes the fossa ovalis.

What forms the crista terminalis in the right atrium?

A ridge separating the smooth sinus venarum from the rough trabeculated atrial appendage.

What is the role of endocardial cushions in AV valve formation?

They contribute to the atrioventricular septum and the septation of the AV canal; AV valves are sculpted from ventricular walls with supporting chordae tendineae.

What does the septum primum contribute to atrial septation?

Forms part of the interventricular septum and participates in the initially open foramen primum that closes as development proceeds.

What does the septum secundum contribute to in atrial septation?

Forms a crescent-shaped septum that with septum primum creates the foramen ovale in the fetal heart.

What terminologies describe the embryonic venous return to the right atrium?

Sinus venosus receives the umbilical, vitelline, and common cardinal veins.

Which structure becomes the left superior vena cava remnants?

Left anterior cardinal vein (and related left-sided venous system) in some cases contributes to persistent left SVC; normally regresses.

What is the function of the ductus venosus in bypassing liver tissue?

Shunts umbilical venous blood directly to the IVC, bypassing the hepatic sinusoids.

Which fetal vessel becomes the ligamentum arteriosum after birth?

Ductus arteriosus.

Which fetal vessel becomes the round ligament of the liver after birth?

Umbilical vein.

What is the neonatal circulation primary adaptation after birth?

Pulmonary and systemic circulations become separate as lungs expand and placental shunts close.

Where does the opening of the sinus venosus connect to in the embryo?

Into the right atrium.

What is the relationship between the pericardial layers in circulation?

Parietal and visceral pericardium (epicardium) surround the heart; the fibrous pericardium lies external as a tough outer layer.

What is the fibrous pericardium’s general location relative to the heart?

It is the outer fibrous layer surrounding the heart, anchoring to the diaphragm and great vessels.

Where are the cho­rionic villi located in relation to maternal blood?

Within the placental structure where chorionic plate is adjacent to maternal intervillous space.

What vascular structure carries deoxygenated blood from the fetus to the placenta?

Umbilical arteries.

What vascular structure carries oxygenated blood from the placenta to the fetus?

Umbilical vein.

Which fetal vessels contribute to the hepatic portal system?

Vitelline veins contribute to the portal vein and liver sinusoids.

Which vessel drains blood from the gut to the liver in fetal life?

Hepatic portal system (formed from vitelline veins).

What happens to the left horn of the sinus venosus during development?

It becomes the coronary sinus.

What structure marks the remodeling of the right atrium’s smooth portion?

Sinus venosus incorporation into the right atrium forms the sinus venarum.

Which embryologic structure becomes the ascending aorta and part of the aortic arch after septation?

A portion derived from the truncus arteriosus via neural crest–driven septation.

What forms the ostium secundum in atrial septation?

Foramen secundum area within septum primum/septum secundum region; creates the foramen ovale complex.

Which artery is associated with the foregut and midgut branches in the embryo?

Celiac trunk (foregut), superior mesenteric, and inferior mesenteric arteries.

What is the function of the oblique vein of the left atrium in relation to the coronary sinus?

It is connected to the coronary sinus region and relates to left atrial venous drainage.

Which structure ensures the separation of systemic and pulmonary circulations after birth?

The functional closure of the foramen ovale, ductus arteriosus, and ductus venosus.

What is the fate of the umbilical arteries after birth in simple terms?

They become the medial umbilical ligaments.

Which embryonic structure gives rise to the pulmonary arteries and parts of the aorta?

Conotruncal (neural crest–driven) septation of the truncus arteriosus.

What is the role of neural crest cells in heart development?

They contribute to the formation of the aortico-pulmonary septum and other outflow tract structures.

Which part of the heart's septation closes the foramen primum to create the foramen ovale?

Fusion of septum primum with the endocardial cushions; septum secundum forms the ostium secundum.

Which layer covers the surface of the heart as the epicardium?

Visceral pericardium (epicardium), part of the serous pericardium.

What is the primary source of the endocardial cushions?

Endocardial cushions from the atrioventricular canal contribute to AV septation and valve formation.

Which structures form the fibrous skeleton of the heart during development?

Endocardial cushions contribute to the atrioventricular septum and valve annuli.

What is the embryologic basis for the right atrium’s smooth area?

Incorporation of the sinus venosus (right horn) into the right atrium forms the smooth sinus venarum.

What is the fate of the left common cardinal vein in normal development?

Contributes to the coronary sinus and venous drainage; the left-sided veins largely regress in normal development.

What is the main function of the placenta in fetal circulation?

Gas exchange, nutrient delivery, and waste removal between maternal and fetal blood.

Which structure carries deoxygenated blood from the fetus to the placenta?

Umbilical arteries.

Which structure carries oxygenated blood from the placenta to the fetus?

Umbilical vein.

What is the fetal counterpart of the ligamentum teres?

Round ligament of the liver (ligamentum teres) derived from the left umbilical vein.

What is the fetal counterpart of the ligamentum arteriosum?

Ductus arteriosus.

What is the fetal counterpart of the ligaments around the liver in the fetus?

Ductus venosus becomes the ligamentum venosum; umbilical vessels form ligaments (medial umbilical ligaments and round ligament, etc.).