At which of the following ages does renal tubular secretion reach ...

[berenicecastro]

At which of the following ages does renal tubular secretion reach adult levels?
 
  a. 2-3 weeks of age
  b. 2 months of age
  c. 5 months of age
  d. 7 months of age

Question 2

Review the following statements and select the one that would be the guiding principle for a health care provider ordering drug therapy for a premature neonate.
 
  a. Metabolic rates are half that of an adult.
  b. There is increased body water as compared to adults.
  c. Heart rate and cardiac output are lower than adults.
  d. There is increased albumin concentration and plasma protein binding as compared to adults.

[Ashley I]

Answer to Question 1

ANS: D
An infant has fewer tubular cells, shorter tubule length, and smaller rates of tubular blood flow. An infant's renal tubular secretion capacity is subsequently less than an adult's, and the half-life of drugs cleared by tubular secretion is again increased. Tubular secretion reaches adult levels by about 7 months of age.

Answer to Question 2

ANS: B
The amount and distribution of total body water (intracellular and extracellular) varies with age. Water, the major constituent of body tissues, is the medium in which solutes are dissolved and all metabolic reactions take place. A premature infant's weight is 86 body water, whereas a full-term neonate's weight is 75 body water. In the immediate postnatal period, as the infant adjusts to a new environment, there is a physiologic loss of body water amounting to 5 of body weight. During the first year of life the proportion of body water decreases to 60 of body weight. The adult male's body weight is 55 water, and the adult female's body weight is 50 water.

[berenicecastro]

TYSM

[apple]

Excellent