Basic Sciences and Anatomy Flashcards

The glossopharyngeal nerve (CN IX) provides sensory innervation to the:

Answer: Posterior one-third of the tongue and pharynx

CN IX carries general and special sensory (taste) fibers from the posterior one-third of the tongue and general sensory fibers from the pharynx.

In the cardiovascular system, the sinoatrial (SA) node functions as:

Answer: The primary pacemaker of the heart

The SA node spontaneously depolarizes at 60 to 100 bpm under normal conditions, initiating each heartbeat and serving as the heart primary pacemaker.

Which respiratory muscle is the primary driver of normal quiet (tidal) breathing?

Answer: Diaphragm

The diaphragm accounts for approximately 70 to 80 percent of tidal volume generation during normal quiet breathing.

The functional residual capacity (FRC) is important in anesthesia because it:

Answer: Is the oxygen reserve that delays desaturation during apnea

FRC is the lung volume at end-expiration and represents the oxygen reservoir available during apnea; lower FRC leads to faster desaturation.

During a Valsalva maneuver, intrathoracic pressure increases, which initially causes:

Answer: A decrease in venous return leading to decreased cardiac output

Elevated intrathoracic pressure compresses the great veins, impeding venous return and reducing preload, transiently decreasing cardiac output.

The hepatic first-pass effect refers to:

Answer: Metabolism of orally administered drugs in the liver before reaching systemic circulation

After oral absorption, drugs pass through the portal circulation to the liver where they may be extensively metabolized, reducing the amount of active drug reaching systemic circulation.