Basic Sciences Flashcards

In the context of EDAIC pharmacology, the volume of distribution (Vd) of a drug is best described as:

Answer: A theoretical volume relating dose to plasma concentration

Vd = Dose / Cp, a theoretical construct reflecting how extensively a drug distributes into tissues relative to plasma.

Which enzyme is responsible for the metabolism of remifentanil, giving it an ultra-short context-sensitive half-time?

Answer: Non-specific blood and tissue esterases

Remifentanil contains an ester linkage hydrolyzed by ubiquitous non-specific esterases in blood and tissues, making its elimination independent of organ function.

The Frank-Starling mechanism describes the relationship between:

Answer: Ventricular end-diastolic volume and stroke volume

The Frank-Starling law states that stroke volume increases as end-diastolic volume (preload) increases, up to a physiological limit.

Which region of the nephron is the PRIMARY site of sodium reabsorption under aldosterone's influence?

Answer: Distal tubule and collecting duct

Aldosterone acts on principal cells of the distal tubule and collecting duct to upregulate Na+/K+-ATPase and ENaC channels, increasing sodium reabsorption.

Minimum alveolar concentration (MAC) of a volatile anesthetic is defined as the concentration that prevents movement in response to surgical incision in what percentage of patients?

Answer: 50%

MAC is the alveolar concentration at 1 atm that prevents purposeful movement in 50% of patients in response to a standard noxious stimulus.

Type II pneumocytes differ from Type I pneumocytes in that they:

Answer: Produce surfactant and can regenerate Type I cells

Type II pneumocytes secrete pulmonary surfactant to reduce alveolar surface tension and serve as progenitor cells capable of regenerating Type I cells after injury.

Which ion channel is responsible for the pacemaker current (If) in the sinoatrial node?

Answer: HCN (hyperpolarization-activated cyclic nucleotide-gated) channel

The funny current (If) flows through HCN channels activated by hyperpolarization, carrying a mixed Na+/K+ inward current that drives spontaneous phase 4 depolarization.