The pharmacokinetics of a drug involve its passage
through various cellular membranes. Understanding the
transport mechanisms and the physicochemical
properties of molecules and membranes is essential to
comprehend the distribution of drugs in the human body.
Regarding the passage of drugs through membrane
barriers, judge the following statements as true (T) or
false (F):
(__)The plasma membrane is fluid and flexible, due to the
presence of microdomains, such as "lipid rafts," and is
organized with proteins that function as structural
anchors, receptors, ion channels, and transporters.
(__)The Na+/K+-ATPase pump is an important example
of facilitated diffusion, which is one of the therapeutic
targets of digoxin used in the treatment of heart failure.
(__)In passive transport, the drug moves by diffusion
following a concentration gradient, depending on its
solubility in the lipid bilayer, the concentration gradient,
the partition coefficient, and the membrane area.
Select the alternative in which the respective order of
judgment is correct: