Pediatric Physiology Lecture 4

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At what week can the initial external genitals be appreciated and the sex of the fetus determined?

10th week

14th week

12th week (correct)

16th week

What measure is used for gestational age and growth assessment in the second trimester and beyond?

Head circumference only

Combination of biometric measures (correct)

Biparietal diameter only

Femoral diaphysis length only

What happens to the length of the fetus in the third trimester?

It doubles (correct)

It triples

It quadruples

It remains the same

What increases in the third trimester, contributing to the weight gain of the fetus?

Body stores of protein, fat, iron, and calcium Signup and view all the answers

What system is discussed in Section II of the outline?

Nervous System Signup and view all the answers

What is the topic of Section VI of the outline?

Renal System Signup and view all the answers

What is the title of Section VIII of the outline?

In Utero Signup and view all the answers

What is the topic of Section X of the outline?

Fetal Circulation Signup and view all the answers

Where does hematopoiesis occur in the embryonic structure during the Mesoblastic Stage?

Yolk sac Signup and view all the answers

What is the sequence of fetal hematopoiesis?

Yolk sac → Liver → Bone marrow Signup and view all the answers

What is the main site of EPO production in the fetus?

Fetal liver Signup and view all the answers

How long does the RBC life span last in a fetus?

60 to 90 days Signup and view all the answers

When do myeloid progenitor cells migrate to the bone marrow?

11th to 12th week of gestation Signup and view all the answers

Why do newborns not become ill despite having quantitative and qualitative deficiencies in their innate and acquired immunity?

It is an adaptive mechanism to optimize survival Signup and view all the answers

What is unique about megakaryopoiesis in the neonatal period?

Rapid proliferation and full cytoplasmic maturation without polyploidization Signup and view all the answers

What is produced by the fetus and not by the mother in the regulation of fetal erythropoiesis?

Erythropoietin (EPO) only Signup and view all the answers

What percentage of fetal hemoglobin is present at 24 weeks AOG?

90% Signup and view all the answers

What is the range of venous partial pressure of oxygen in the placenta?

35-40 mmHg Signup and view all the answers

Why does the oxygen dissociation curve of HbF shift to the left?

Because of its higher affinity for oxygen Signup and view all the answers

What is the result of HbF's lower affinity for diphosphoglycerate?

Shift to the left Signup and view all the answers

What happens to the capacity to maintain a higher oxygen content after birth?

It is no longer needed Signup and view all the answers

What is the environment like in the pulmonary capillaries after birth?

High oxygen tension Signup and view all the answers

What happens to the output from the right ventricle after the umbilical cord is cut?

It flows entirely into the pulmonary circulation Signup and view all the answers

What is the main factor controlling the closure of the ductus arteriosus?

Increased oxygen levels Signup and view all the answers

What is the name of the syndrome related to respiratory distress?

Respiratory Distress Syndrome Signup and view all the answers

What is the figure number that shows the respiratory system?

Figure 8 Signup and view all the answers

Why does the shunt through the ductus arteriosus reverse after birth?

Because pulmonary vascular resistance becomes lower than systemic vascular resistance Signup and view all the answers

What happens to the foramen ovale after birth?

It closes due to the increased volume of pulmonary blood flow returning from the lungs Signup and view all the answers

What happens to the ductus venosus after birth?

It closes after the removal of the placenta from circulation Signup and view all the answers

What happens to the left ventricle after birth?

It becomes coupled to the high-pressure systemic circulation Signup and view all the answers

By what time is the ductus arteriosus typically closed in term infants?

Within 60 hours after birth Signup and view all the answers

What is the result of the increased volume of pulmonary blood flow returning from the lungs to the left atrium?

Closure of the foramen ovale Signup and view all the answers

What is the primary function of the fetal kidney?

To produce a large amount of urine for amniotic fluid Signup and view all the answers

When do renal control systems start to regulate fetal extracellular fluid volume and electrolyte imbalance?

During late fetal life Signup and view all the answers

What percentage of cardiac output is represented by renal blood flow in the first postnatal week?

4-6% Signup and view all the answers

What causes the initial low renal blood flow in the first postnatal week?

Elevated levels of vasoconstrictor hormones Signup and view all the answers

What happens to the distribution of renal blood flow postnatally?

More flow to the cortex Signup and view all the answers

At what gestational age do fetuses have 1 million nephrons, but are still immature?

34 weeks Signup and view all the answers

What percentage of amniotic fluid is accounted for by fetal urine?

70-80% Signup and view all the answers

What is the consequence of abnormal kidney development or severe impairment of kidney function in the fetus?

Oligohydramnios Signup and view all the answers

When does the production of urine by the fetus start?

Second trimester Signup and view all the answers

What is the characteristic of the glomerular filtration rate (GFR) in fetuses at 34 weeks of gestational age?

Immature and reduced Signup and view all the answers