Aorta -Pulmonary trunk (a) Ventricular septal defect. The superior part of the interventricular septum fails to form; thus, blood mixes between the two ventricles. (b) Transposition of the great vessels. Aorta comes from right ventricle; pulmonary trunk from left. Results when the bulbus cordis does not divide properly. Unoxygenated blood passes repeatedly around systemic circuit, while oxygenated blood recycles around the pulmonary circuit. More blood is shunted from left to right because the left ventricle is stronger. Occurs in about 1 in every 500 births Occurs in about 1 in every 1000 births - Narrowed aorta (d) Tetralogy of Fallot. Multiple defects (tetra = four): (1) Pulmonary trunk too narrow and pulmonary valve stenosed, resulting in (2) hypertrophied right ventricle; (3) ventricular septal defect; (4) aorta opens from both ventricles. (c) Coarctation of the aorta. A part of the aorta is narrowed, increasing the workload of the left ventricle. Ocurs in about 1 in every 1500 births Occurs in about 1 in every 2000 births Figure 19.18 Congenital Heart Defects. The defects are shown according to relative frequency of occurrence, from the most frequent to the least. Tan areas indicate the locations of the defects.

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Question

Classify the three congenital heart defects—ventricular septal defect, coarctation of the aorta, and tetralogy of Fallot (Figure 19.18)— according to whether they produce (1) mixing of oxygenated and unoxygenated blood, (2) increased workload for the ventricles, or (3) both of these problems.