Placental and Fetal Circulation Quiz

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Where does the pulmonary trunk arise from?

Right atrium

Left ventricle

Left atrium

Right ventricle (correct)

What is the source of oxygenated blood that supplies the supporting tissues of the lungs?

Renal arteries

Systemic arteries (correct)

Pulmonary arteries

Coronary arteries

Where does the oxygenated bronchial arterial blood empty after passing through the supporting tissues of the lungs?

Pulmonary arteries

Right atrium

Pulmonary veins (correct)

Left atrium

What is the function of the capillary plexus in pulmonary circulation?

Supplies oxygen to the alveolar air Signup and view all the answers

What role do the pulmonary veins play in the circulation of oxygenated blood?

Convey oxygenated blood to the left atrium Signup and view all the answers

Where does the umbilical vein transport blood from the placenta to the fetus?

To the liver Signup and view all the answers

What happens to the blood that enters the fetal right atrium?

It is shunted directly into the left atrium through the foramen ovale Signup and view all the answers

Why does blood largely bypass the fetal lungs?

Because the fetal lungs are nonfunctional Signup and view all the answers

What happens to the blood in the pulmonary trunk in fetal circulation?

Bypasses the lungs through a fetal vessel called ductus arteriosus Signup and view all the answers

What contributes to the remarkable resistance to hypoxia in fetal and newborn mammals?

Greater O2 affinity of fetal red cells than adult red cells Signup and view all the answers

Which of the following is responsible for the most significant alterations in pulmonary blood flow by producing vasoconstriction?

Local hypoxia Signup and view all the answers

What plays an important role in up-regulating uterine blood flow during pregnancy?

Corticotrophin-releasing hormone Signup and view all the answers

Which circulation starts with the maternal blood flow into the intervillous space through decidual spiral arteries?

Placental Circulation Signup and view all the answers

What do J receptors adjacent to pulmonary capillaries stimulate when activated?

Reflex tachypnoea and reduction of skeletal muscle tone Signup and view all the answers

What leads to reflex dilatation of pulmonary vessels?

Baroreceptor stimulation Signup and view all the answers

What contributes to the expansion of the infant's lungs during the first gasps?

Markedly negative intrapleural pressure Signup and view all the answers

What effect does the sucking action of the first breath have on blood circulation?

It squeezes blood from the placenta Signup and view all the answers

What happens to the pulmonary vascular resistance once the infant's lungs are expanded?

It decreases to less than 20% of its utero value Signup and view all the answers

What causes the closure of the foramen ovale in the infant's heart?

Rising pulmonary blood flow Signup and view all the answers

When does the ductus arteriosus undergo permanent anatomic closure in infants?

Within 24-48 hours after birth Signup and view all the answers