Embryonic Heart Development Quiz

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Questions and Answers

What structure is formed by the migration of splanchnic mesoderm near the liver into the cardiac region?

Pericardium

Endocardium

Epicardium (correct)

Myocardium

What is the primary outcome of cardiac looping during embryonic development?

Correct spatial relationship of heart chambers (correct)

Division of the sinus venosus

Closure of the foramen primum

Formation of the atrioventricular valves

From which veins does blood enter the sinus venosus from the embryo?

Common cardinal veins (correct)

Pulmonary veins

Renal veins

Umbilical veins

What plays a critical role in dividing the atrioventricular canal into right and left atrioventricular canals?

Endocardial cushions Signup and view all the answers

What is the role of the foramen secundum during atrial development?

Allows blood to flow from the right atrium to left atrium Signup and view all the answers

What is the fate of the foramen primum during heart development?

It closes when the septum primum fuses with endocardial cushions Signup and view all the answers

What occurs before the foramen primum disappears during heart development?

Perforations are produced by apoptosis in septum primum Signup and view all the answers

What do the paired anterior cardinal veins drain?

The head region Signup and view all the answers

From which structure does blood enter the sinus venosus?

Common cardinal veins Signup and view all the answers

What is formed when the truncal and bulbar ridges fuse?

Aorticopulmonary septum Signup and view all the answers

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

It is reduced and becomes the coronary sinus Signup and view all the answers

Which vessels drain well-oxygenated blood into the developing heart?

Umbilical veins Signup and view all the answers

Which two structures does the aorticopulmonary septum divide?

Aorta and pulmonary trunk Signup and view all the answers

What is formed from the fusion of tissues from the right bulbar ridge, left bulbar ridge, and endocardial cushion?

Membranous interventricular septum Signup and view all the answers

What developmental process gives rise to the semilunar valve leaflets?

Swelling of subendocardial tissue Signup and view all the answers

Which structure primarily incorporates the primordial pulmonary vein during atrial development?

Left atrium Signup and view all the answers

What structure does the aorticopulmonary septum continue with?

Membranous interventricular septum Signup and view all the answers

Which components are derived from endocardial-derived cushion tissue?

Semilunar valve leaflets Signup and view all the answers

During which week does the active proliferation of cells in the walls of the bulbus cordis occur?

5th week Signup and view all the answers

What separates the right and left ventricles in early heart development?

Interventricular septum Signup and view all the answers

What becomes of the left anterior cardinal vein during the remodeling of the heart?

It connects to the right anterior cardinal vein Signup and view all the answers

What role does the foramen ovale play during fetal circulation?

It permits blood to move from the right atrium directly to the left atrium. Signup and view all the answers

What triggers the functional closure of the foramen ovale immediately after birth?

A decrease in right atrial pressure and an increase in left atrial pressure. Signup and view all the answers

Which structure directs blood away from the lungs in the fetal circulation?

Ductus arteriosus Signup and view all the answers

What anatomical structure grows from the muscular ventrocranial wall of the atrium?

Septum secundum Signup and view all the answers

What is the end product of the fusion of the septum primum and septum secundum?

Oval fossa (fossa ovalis) Signup and view all the answers

During the transitional circulation after birth, which of the following occurs?

Lung function begins and lung blood flow increases. Signup and view all the answers

What physiological change occurs in the right and left atrial pressures that facilitates the closure of the foramen ovale at birth?

Right atrial pressure decreases and left atrial pressure increases. Signup and view all the answers

How does fetal circulation bypass pulmonary circulation?

Using the foramen ovale and ductus arteriosus. Signup and view all the answers

What is the primary difference between vasculogenesis and angiogenesis?

Vasculogenesis is the formation of a primitive vascular network, whereas angiogenesis refers to the growth of new capillaries from existing blood vessels. Signup and view all the answers

During which week does the embryonic body cavity become divided into three well-defined cavities?

Fourth week Signup and view all the answers

What role does vascular endothelial growth factor (Vegf) play in the development of the cardiovascular system?

It directs the differentiation of a subset of cells into endothelial and endocardial cells. Signup and view all the answers

What is the structure formed from the fusion of the two limbs of the cardiac crescent?

The primitive heart tube Signup and view all the answers

Which component makes up the primary heart tube?

Myocardial tube Signup and view all the answers

What is the function of the umbilical vein in the developing embryo?

To carry well-oxygenated blood and nutrients from the chorionic sac to the embryo. Signup and view all the answers

What role does cardiac jelly play in the cardiovascular system?

It provides a thick layer of extracellular matrix secreted by the myocardium. Signup and view all the answers

Which feature characterizes the new capillaries formed through angiogenesis?

They lack a fully developed tunica media. Signup and view all the answers

Study Notes

Development of the Cardiovascular System-I

Vasculogenesis and angiogenesis are fundamental processes in blood vessel formation.
Vasculogenesis is the differentiation of endothelial precursor cells (angioblasts) into endothelial cells, creating a primitive vascular network.
Angiogenesis is the growth of new capillaries (lacking a fully developed tunica media) from existing blood vessels.
The cardiac crescent forms within the splanchnic mesoderm.
The intraembryonic coelom develops into the embryonic body cavity, divided into three cavities (pericardial, pericardioperitoneal, peritoneal) during the fourth week.
Pericardiac mesoderm forms the heart-forming regions.
The cranial-most portion of the cardiac crescent shifts ventrally and caudally, positioned ventral to the foregut endoderm.
During the head fold, the pericardial coelom moves ventral to the heart tube and caudal to the oropharyngeal membrane.
Endocardial tubes coalesce into a single tube, forming the primitive heart tube.
The embryo folds cephalocaudally and transversely to bring the two heart tubes closer.
The two endocardial heart tubes fuse in the cephalo-caudal direction.
The heart tube is attached to the dorsal side of the pericardial cavity by the dorsal mesocardium.
Cardiogenic cords differentiate into endocardial heart tubes.
The primitive heart tube begins to elongate and bend into a C-shape, with the bend extending to the right side.
This looping process establishes the proper spatial relationship for the four chambers of the heart.
The heart's chambers progressively form (truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and sinus venosus).

Major Cardiovascular Structures

The four presumptive chambers of the future heart are brought together through cardiac looping.
The primary heart tube comprises an endocardial tube, cardiac jelly, and myocardial tube.
The innermost endothelial tube becomes the endocardium.
The outermost myocardial tube, a mass of splanchnic mesoderm, forms the myocardium.
The layer of extracellular matrix around the myocardium is the cardiac jelly.
Splanchnic mesoderm migrating from the coelomic wall near the liver forms the epicardium.
The tubular heart elongates and develops alternative dilations and constrictions, forming the truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and sinus venosus.

Development of the Heart Valves

Semilunar valves develop from three swellings of subendocardial tissue around the orifices of the aorta and pulmonary trunk; these swellings become hollowed out and reshaped, forming three thin-walled cusps.
Semilunar valve leaflets originate from endocardial-derived cushion tissue.
Atrioventricular valves (tricuspid and mitral valves) develop similarly from localized proliferations of tissue around the atrioventricular canals.
The bulbar ridges and truncal ridges, primarily derived from neural crest cells, grow, twist, and interact spirally, potentially influenced by blood flow from the ventricles.
The aorticopulmonary septum develops from ridges, dividing the bulbus cordis and truncus arteriosus.
The pulmonary trunk twists around the ascending aorta due to spiraling of the aorticopulmonary septum.

Formation of Atrial Septum

The primordial atrium is divided into right and left atria through the formation and modification of two septa-the septum primum and septum secundum.
The septum primum grows toward the fusing endocardial cushions, partially separating the atrium into right and left halves.
The foramen primum—a large opening between the free edge and endocardial cushions—forms as the septum primum develops.
The foramen primum closes when the septum primum fuses with the atrioventricular cushions.
Perforations produced by apoptosis develop in the central part of the septum primum and coalesce to form the foramen secundum.
The septum secundum develops from the muscular ventrocranial wall, adjacent to the right side of the septum primum.
The foramen ovale is the opening between the upper and lower limbs of the septum secundum.
During embryonic life, the foramen ovale shunts blood from the right atrium to the left.

Fetal Heart Circulation

In the fetus, most blood bypasses the lungs through the foramen ovale, which is an opening between the atria (right to left), and the ductus arteriosus that connects the pulmonary artery and the aorta.
Blood from the embryo enters the sinus venosus through the common cardinal veins (poorly oxygenated) and from the developing placenta via the umbilical veins (well-oxygenated).
Blood leaves the truncus arteriosus, enters the aortic sac, and is distributed to pharyngeal arch arteries.
The closure of the interventricular foramen and formation of the membranous interventricular septum result from the fusion of the right and left bulbar ridges and endocardial cushions.

Transitional Circulation

Transitional circulation is when fetal circulation changes to the neonatal phenotype.
It begins when the umbilical cord is clamped, and the lungs begin aeration.
Elimination of placental circulation, expansion of lungs, increase in lung blood flow, closure of the foramen ovale, ductus arteriosus, and ductus venosus are key components of the transition.
The period of time for this transition to complete varies, but it generally happens soon after birth.
Factors like cold stimuli or the first few breaths after birth contribute to the transition.

Congenital Heart Defects

Some congenital conditions include Atrioventricular septal defect, Hypoplastic left heart syndrome, Tetralogy of Fallot, Ventricular septal defect, Transposition of great arteries, Coarctation of the aorta, Double outlet right ventricle, Aortic stenosis, Tricuspid atresia, Single ventricle, Ebstein's anomaly, Common arterial trunk, Pulmonary atresia, and Pulmonary atresia with an intact ventricular septum, as well as others.

Specific Cardiovascular Anomalies

Truncus arteriosus is a congenital defect where the fetus or newborn baby has just one large blood vessel emerging from the heart instead of two separate vessels.
Atrial septal defect is a structural anomaly where the septum between the atria has an opening, allowing oxygenated blood from the left atrium to flow into the right atrium.
Ventricular septal defect is a condition where the ventricular septum has an opening, obstructing oxygenated blood from the left ventricle from flowing into the right ventricle.
Tetralogy of Fallot involves four cardiac anomalies: ventricular septal defect, overriding of the aorta, narrowing of the pulmonary outflow tract and thickening of the right ventricular wall.
Atrioventricular canal (Endocardial cushion defect) is an anomaly where the division of the primordial ventricle to two ventricles isn't completely formed.

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Description

Test your knowledge on the complex processes of heart development during embryogenesis. This quiz covers various aspects such as cardiac looping, atrioventricular canal division, and the fate of the foramen primum and secundum. Perfect for students studying developmental biology or embryology.