NBDHE NBDHE Scientific Basis of Practice 3

Question 1

Which enzyme converts arachidonic acid into prostaglandins and thromboxanes?

Accepted Answer

Cyclooxygenase (COX)

Answer

Cyclooxygenase (COX-1 and COX-2) catalyzes the first steps in converting arachidonic acid to prostaglandins, prostacyclin, and thromboxane A2.

Question 2

A histologic section shows columnar cells with nuclei polarized away from the basement membrane and active secretory vesicles. Which cell type is depicted?

Accepted Answer

Ameloblast

Answer

Ameloblasts are tall columnar cells with Tomes' processes and nuclei polarized away from the enamel-forming surface during amelogenesis.

Question 3

Which pharmacologic effect of epinephrine accounts for its use as a vasoconstrictor in local anesthetic solutions?

Accepted Answer

Alpha-1 receptor stimulation causing vasoconstriction

Answer

Epinephrine acts on alpha-1 adrenergic receptors in peripheral vasculature to cause vasoconstriction, reducing systemic absorption of the local anesthetic.

Question 4

Which type of hypersensitivity reaction is responsible for contact dermatitis from latex gloves?

Accepted Answer

Type IV (delayed/cell-mediated)

Answer

Contact dermatitis from latex is a Type IV delayed hypersensitivity reaction mediated by sensitized T lymphocytes, occurring 24–72 hours after exposure.

Question 5

During embryonic development, failure of fusion of the maxillary and medial nasal processes results in which condition?

Accepted Answer

Cleft lip

Answer

Cleft lip results from failure of the maxillary process to fuse with the medial nasal process during the 5th–6th weeks of embryonic development.

NBDHE Test Practice Test

NBDHE Test Practice Test

NBDHE NBDHE Scientific Basis of Practice 3