NBDE Part I flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Foramen ovale

Opening in the greater wing of the sphenoid that transmits the mandibular division of the trigeminal nerve (V3) and the accessory meningeal artery.

Lateral pterygoid muscle

Only muscle of mastication that depresses and protrudes the mandible; acting alone, it shifts the mandible to the opposite side. Innervated by V3.

Chorda tympani

Branch of the facial nerve (CN VII) carrying taste from the anterior two-thirds of the tongue and secretomotor fibers to the submandibular and sublingual glands.

Hypoglossal nerve

Cranial nerve XII; provides motor innervation to all intrinsic and extrinsic tongue muscles except palatoglossus, which is supplied through the pharyngeal plexus (CN X).

Carotid sheath contents

Fibrous sheath containing the common carotid artery, internal jugular vein, and vagus nerve, running from the skull base to the root of the neck.

TMJ articular surfaces

The temporomandibular joint is a bilateral ginglymoarthrodial synovial joint whose articular surfaces are covered by fibrocartilage rather than hyaline cartilage, permitting both rotation and translation.

Middle meningeal artery

Branch of the maxillary artery that enters the cranium through the foramen spinosum; tearing in temporal bone fracture produces an epidural hematoma.

Submandibular ganglion

Parasympathetic ganglion suspended from the lingual nerve; relay site for chorda tympani secretomotor fibers to the submandibular and sublingual salivary glands.

Phosphofructokinase-1

Rate-limiting enzyme of glycolysis converting fructose-6-phosphate to fructose-1,6-bisphosphate; activated by AMP and fructose-2,6-bisphosphate, inhibited by ATP and citrate.

Competitive inhibition

Inhibitor binds reversibly at the enzyme active site, raising apparent Km while leaving Vmax unchanged; the inhibition is overcome by increasing substrate concentration.

Bohr effect

Rightward shift of the oxyhemoglobin dissociation curve caused by increased PCO2, decreased pH, increased temperature, or increased 2,3-BPG, reducing hemoglobin oxygen affinity.

SGLT2

Sodium-glucose cotransporter in the proximal convoluted tubule that reabsorbs most filtered glucose; its inhibition increases urinary glucose excretion.

Aldosterone action

Mineralocorticoid acting on the distal tubule and collecting duct to increase sodium reabsorption and potassium secretion, thereby expanding extracellular fluid volume.

Resting membrane potential

Approximately -70 mV in most neurons and muscle cells, established mainly by potassium leak conductance and maintained by the electrogenic Na+/K+ ATPase.

Vitamin C and collagen

Ascorbic acid is a cofactor for prolyl and lysyl hydroxylase; deficiency reduces collagen cross-linking and causes scurvy with bleeding gums and poor wound healing.

Na+/K+ ATPase

Electrogenic pump moving three sodium ions out of the cell and two potassium ions in per ATP hydrolyzed, maintaining ionic gradients and the resting membrane potential.

Streptococcus mutans

Principal cariogenic bacterium; uses glucosyltransferase to build glucans from sucrose, adheres to the acquired pellicle, and produces acid from fermentable carbohydrate.

Lipopolysaccharide endotoxin

Outer membrane component of gram-negative bacteria; lipid A activates TLR4, triggering cytokine release, fever, and potentially septic shock.

Type IV hypersensitivity

Cell-mediated delayed hypersensitivity mediated by T cells and macrophages, peaking at 48-72 hours; examples include the tuberculin reaction and contact dermatitis.

Porphyromonas gingivalis

Gram-negative, black-pigmented anaerobic rod strongly associated with chronic periodontitis; fimbriae, gingipains, and lipopolysaccharide drive periodontal tissue destruction.

Autoclave parameters

Moist-heat sterilization at 121 degrees Celsius and 15 psi for 15-20 minutes, which destroys bacteria, viruses, and spores; standard for dental instruments.

Leukoplakia

Predominantly white patch of oral mucosa that cannot be rubbed off and cannot be classified clinically as any other disease; considered potentially malignant.

Granuloma

Nodular aggregate of activated epithelioid macrophages, often with multinucleated giant cells and lymphocytes, characteristic of chronic granulomatous inflammation.

Squamous cell carcinoma

Most common oral malignancy, arising from stratified squamous epithelium; risk factors include tobacco, alcohol, and betel quid; often presents as a nonhealing ulcer.

Universal tooth 1

In the universal numbering system, tooth 1 is the maxillary right third molar; numbering proceeds to tooth 32, the mandibular right third molar.

FDI quadrant 3

In FDI notation the first digit indicates the quadrant (3 = mandibular left) and the second the tooth position from the midline, giving teeth 31 through 38.

Maxillary first molar anatomy

Typically has three roots (mesiobuccal, distobuccal, palatal) and four canals, because the mesiobuccal root usually contains two separate canals.

Angle Class II

Mandibular first molar lies distal to its Class I position; the mesiobuccal cusp of the maxillary first molar occludes mesial to the mandibular buccal groove.

Canine guidance

Occlusal scheme in which working-side canines contact during lateral excursion and disclude the posterior teeth, reducing lateral forces on molars.

Curve of Spee

Anteroposterior curvature of the occlusal plane, concave upward in the mandible, running from the canine through the molars toward the condyle.

Bennett movement

Lateral bodily shift of the mandible toward the working side during lateral excursion; the nonworking condyle moves forward, downward, and medially.

Mandibular first molar eruption

Erupts at approximately 6 years of age, making it the first permanent tooth to erupt; it does not replace a deciduous predecessor.