Basic Sciences and Anatomy Flashcards

Which neurotransmitter is the primary inhibitory neurotransmitter in the central nervous system?

Answer: Gamma-aminobutyric acid (GABA)

GABA is the primary inhibitory neurotransmitter in the CNS. Most sedatives and anxiolytics (benzodiazepines, barbiturates, propofol) act by potentiating GABA-A receptor activity.

The blood-brain barrier (BBB) affects drug distribution because:

Answer: Lipid-soluble drugs cross it more easily than water-soluble drugs

The BBB consists of tight junctions between cerebral capillary endothelial cells. Lipid-soluble, unionized, protein-unbound drugs traverse it most readily.

The autonomic nervous system parasympathetic response is best described as:

Answer: Rest-and-digest, slowing heart rate and increasing gastrointestinal activity

Parasympathetic activation (via acetylcholine/muscarinic receptors) decreases heart rate, increases GI motility, promotes salivation, and conserves energy.

The inferior alveolar nerve (IAN) block targets the nerve before it enters the:

Answer: Mandibular foramen

The IAN block is deposited near the mandibular foramen on the medial surface of the ramus, where the nerve enters the mandibular canal.

During rapid IV administration of lidocaine, which central nervous system toxic effect appears first?

Answer: Circumoral numbness and tinnitus (early warning signs)

Local anesthetic toxicity follows a progression: early CNS excitatory signs (tinnitus, metallic taste, circumoral numbness) precede seizures, then CNS depression and cardiovascular collapse.

Which anatomical landmark is used to identify the correct needle insertion point for a posterior superior alveolar (PSA) nerve block?

Answer: Mucobuccal fold above the maxillary second molar

The PSA block needle is inserted at 45 degree angles in the mucobuccal fold distal to the maxillary second molar to anesthetize the PSA nerve.