The Heart Practice MCQ's - The Cardiovascular System (I): The Heart

The muscular portion of the interventricular septum develops from the growth of the myocardium. This means that the muscle tissue in the septum is formed through the expansion and development of the heart muscle itself. This process occurs during embryonic development and continues as the heart grows and matures. Therefore, the statement is true.

During the development of the fetal heart, the right horn of the sinus venosus contributes to the formation of the right atrium. The sinus venosus is a part of the developing heart that receives deoxygenated blood from the veins. As the heart develops, the right horn of the sinus venosus specifically contributes to the formation of the right atrium, which is responsible for receiving deoxygenated blood from the body and pumping it into the right ventricle.

The splanchnic mesoderm gives rise to the endocardial heart tubes. The endocardial heart tubes are the precursor of the heart and are formed during early embryonic development. The splanchnic mesoderm is one of the three layers of the mesoderm, along with the paraxial and intermediate mesoderm. It is located closest to the developing gut and plays a crucial role in the formation of various organs, including the heart. Therefore, the correct answer is splanchnic mesoderm.

The truncus arteriosus gives rise to the pulmonary artery and the aorta. During embryonic development, the truncus arteriosus is a part of the primitive heart tube that eventually divides into two separate vessels, forming the pulmonary artery and the aorta. This division allows for the proper separation of oxygenated and deoxygenated blood flow in the developing cardiovascular system.

The correct answer is transposition of the great vessels. Transposition of the great vessels is a congenital heart defect where the aorta arises from the right ventricle and the pulmonary trunk arises from the left ventricle. This results in a complete reversal of the normal blood flow pattern. The condition presents with cyanotic heart disease and failure to thrive in newborn infants.

During embryonic development, the heart undergoes several changes to form its final structure. The left sinus horn is a part of the developing heart that eventually becomes the coronary sinus. The coronary sinus is a large vein located in the posterior part of the heart that collects deoxygenated blood from the heart muscle itself and drains it into the right atrium. Therefore, the correct answer is the coronary sinus.

The failure of the aorticopulmonary septum to undergo the 180-degree spiral refers to a developmental abnormality in the heart during embryonic development. This spiral is crucial for the proper alignment of the aorta and pulmonary artery. When this spiral fails to occur, it can lead to the transposition of the great vessels. In transposition of the great vessels, the aorta and pulmonary artery are switched, resulting in the aorta arising from the right ventricle and the pulmonary artery arising from the left ventricle. This condition disrupts the normal blood flow and requires surgical intervention shortly after birth.

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The aorticopulmonary septum does not contribute to the formation of the muscular interventricular septum. The muscular interventricular septum is formed by the growth and fusion of the muscular walls of the ventricles. The aorticopulmonary septum, on the other hand, separates the outflow channel of the ventricles into the aorta and the pulmonary trunk.

The septum primum, a thin and membranous structure, forms during the partitioning of the atria and eventually contributes to the formation of the valve of the oval foramen, which plays a key role in fetal circulation. The other options are incorrect descriptions of the atrial partitioning process.

right sinous horn becomes the sinous venarum of the right ATRIA

The sinus venarum is formed from tissue of the right sinus horn. The right sinus horn is a structure that develops during embryonic development and gives rise to various parts of the heart, including the sinus venarum. This structure contributes to the formation of the right atrium, and specifically, the smooth part of the atrium. The sinus venarum is a smooth-walled area of the right atrium, located between the original atrial wall tissue and the trabeculated part of the atrium.

The correct answer is Truncus arteriosus. The truncus arteriosus is a structure that forms from the primitive heart tube during embryonic development. It is responsible for delivering oxygenated blood to supply the embryo.

The aorticopulmonary septum (also called the spiral septum, ) is developmentally formed from neural crest, specifically the cardiac neural crest

The correct answer states that the molding of the atrioventricular valves is caused by the normal turbulent flow of blood through the ventricles. This means that the shape and structure of the valves are influenced by the movement and pressure of blood as it flows through the heart. This turbulent flow helps to shape and form the valves, allowing them to function properly in regulating blood flow between the atria and ventricles.