NBDHE NBDHE Scientific Basis of Practice 5

Question 1

Which cranial nerve is responsible for motor innervation of the muscles of mastication?

Accepted Answer

Cranial nerve V3 (mandibular)

Answer

The mandibular division (V3) of the trigeminal nerve carries the motor fibers that innervate the masseter, temporalis, medial and lateral pterygoid muscles.

Question 2

A biopsy of an oral ulcer shows acantholysis and loss of intercellular bridges between keratinocytes. Which autoimmune condition does this suggest?

Accepted Answer

Pemphigus vulgaris

Answer

Pemphigus vulgaris is caused by autoantibodies against desmoglein, resulting in acantholysis (separation of keratinocytes) and intraepithelial vesicle formation.

Question 3

Which metabolic pathway produces ATP most efficiently under aerobic conditions?

Accepted Answer

Oxidative phosphorylation via the electron transport chain

Answer

Oxidative phosphorylation in the mitochondria generates approximately 30–32 ATP per glucose molecule, far exceeding the 2 ATP from anaerobic glycolysis.

Question 4

Which organism is the primary causative agent of acute necrotizing ulcerative gingivitis (ANUG)?

Accepted Answer

Fusobacterium nucleatum and Treponema species

Answer

ANUG is associated with a fusospirochetal complex, primarily Fusobacterium nucleatum and Treponema species, in a setting of stress and immune compromise.

Question 5

Aspirin irreversibly inhibits cyclooxygenase in platelets. How long does it take for platelet function to fully recover after aspirin discontinuation?

Accepted Answer

7–10 days

Answer

Since platelets are anucleate and cannot synthesize new COX, platelet function recovers only as new platelets are produced over 7–10 days (the platelet lifespan).

NBDHE Test Practice Test

NBDHE Test Practice Test

NBDHE NBDHE Scientific Basis of Practice 5