Developmental Pathophysiology, Develop. Physiol., Dr. D. Penney

Self-Assessment - Module 23:

    1. In Tetralogy of Fallot:
    1. desaturation of arterial blood occurs
    2. extent of cyanosis is primarily a function of the degree of pulmonary stenosis
    3. may allow equalization of right and left ventricle pressures
    4. right to left shunting of blood is the rule
    5. all are correct.

    2. At birth:

    1. pulmonary vascular resistance falls shortly after the first breath, because of pulmonary arteriolar vasodilation
    2. the initial left atrial pressure rise occurs because the ductus arteriosus has closed.
    3. the foramen ovale closes because of umbilical cord clamping.
    4. right to left shunting of blood through the ductus arteriosus continues right up till the ductus closes.
    5. the adult circulation is functional within a few minutes after birth.

    3. You do oximetry on a young patient with suspected congenital heart disease, with the following results:

    SiteOxygen saturation (%)
    Inferior vena cava69
    Right atrium68
    Right ventricle68
    Pulmonary artery83
    Left atrium98
    Left ventricle98

    The values are most consistent with a diagnosis of:

    1. atrial septal defect
    2. coarctation of the aorta
    3. tricuspid atresia (i.e. valve and opening absent)
    4. patent ductus arteriosus
    5. ventricular septal defect

    4. Which of the following statements are incorrect regarding the oxygen dissociation curve of human hemoglobin?

    1. the affinity for oxygen is decreased by more acid conditions (i.e. lower pH).
    2. the curve is "S' shaped.
    3. blood returning to the right atrium and right ventricle has given up its oxygen to body tissues and is completely lacking in oxygen.
    4. hemoglobin is almost completely saturated with oxygen (93-98%) at 100 mm Hg partial pressure of oxygen.
    5. increasing body temperature lowers hemoglobin's affinity for oxygen.

    5. Which of the following statements best characterizes the ductus venosus of the fetus?

    1. it receives most of its blood from the umbilical vein
    2. it sends its blood to the liver
    3. both of the above statements are correct
    4. it contains blood of a lower oxygen content than the blood in the umbilical arteries
    5. statements A and D are correct

    6. Which one of the following statements is incorrect regarding the ductus arteriosus?

    1. it is a shunt from the pulmonary artery to the aorta in the fetus
    2. blood flow may take place from the aorta to the pulmonary artery after birth, prior its closing.
    3. it is a shunt directly from the right atrium to the left atrium
    4. right to left blood flow decreases with the first breath after birth due to falling pulmonary vascular resistance.
    5. the smooth muscle in its walls is sensitive to rising PO2

    7. The foramen ovale

    1. closes anatomically within seconds to minutes after birth
    2. permits about twice a much blood to pass to the left atrium as that which flows into the right ventricle during fetal life
    3. closes functionally at birth because left atrial pressure rises above right atrial pressure
    4. is a shunt around the liver, allowing blood to flow directly from the umbilical vein to the right atrium
    5. is a round hole in the interventricular septum between the right and left hearts

    8. A patient is diagnosed as having an opening in the interatrial septum uncomplicated by other cardiac abnormalities. Which of the following would best confirm this diagnosis?

    1. a systolic murmur
    2. an elevated oxygen concentration in the right atrium
    3. arterial cyanosis
    4. a decreased pressure in the right atrium
    5. tachycardia

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