With Regard to the Development of the Respiratory System,maternity Nurses

question 19

Multiple Choice

With regard to the development of the respiratory system,maternity nurses should understand that:

• A) the respiratory system does not begin developing until after the embryonic stage.
• B) the infant's lungs are considered mature when the lecithin/sphingomyelin [L/S] ratio is 1:1, at about 32 weeks.
• C) maternal hypertension can reduce maternal-placental blood flow, accelerating lung maturity.
• D) fetal respiratory movements are not visible on ultrasound scans until at least 16 weeks.

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Definitions:

Hormonal Variance

Variations in the levels or activity of hormones in an organism, influencing a wide range of physiological and behavioral outcomes.

Microevolution

Change in allele frequency.

Independent Assortment

A basic principle of genetics developed by Mendel stating that genes for different traits are sorted separately from one another so the inheritance of one trait is not dependent on the inheritance of another.

Crossing Over

Process by which homologous chromosomes exchange corresponding segments of DNA during prophase I of meiosis.