Chapter 2: Drugs and the Body

Question 1

absorption

Answer 1

what happens to a drug from the time it enters the body until it enters the circulating fluid

Question 2

active transport

Answer 2

the movement of substances across a cell membrane; this process requires the use of energy

Question 3

chemotherapeutic agents

Answer 3

synthetic chemicals used to interfere with the functioning of foreign cell populations, causing cell death; this term is frequently used to refer to the drug therapy of neoplasms, but it also refers to drug therapy affecting any foreign cell

Question 4

critical concentration

Answer 4

the concentration a drug must reach in the tissues that respond to the particular drug to cause the desired therapeutic effect

Question 5

distribution

Answer 5

movement of a drug to body tissue; the places where a drug may be distributed depend on the drug’s solubility; perfusion of the area, cardiac output, and binding of the drug to plasma proteins

Question 6

enzyme induction

Answer 6

process by which the presence of a chemical causes increased activity of an enzyme system

Question 7

excretion

Answer 7

removal of a drug format he body; routes include the kidneys, skin, lungs, bile, and feces

Question 8

fire-pass effect

Answer 8

a phenomenon in which drugs given orally are carried directly to the liver after absorption, where they may be largely inactivated by liver enzymes before they can enter the general circualtion

Question 9

glomerular filtration

Answer 9

the passage of water and water-soluble components from the plasma into the renal tubule

Question 10

half-life

Answer 10

the time it takes for the amount of drug in the body to decrease to one-half of the peak level it achieved

Question 11

hepatic microsomal system

Answer 11

liver enzymes tightly packed together in the hepatic intracellular structure, responsible for the biotransformation of chemicals, including drugs

Question 12

loading dose

Answer 12

a dose higher than what is usually used for treatment, administered to allow the drug to reach the critical concentration sooner

Question 13

passive diffusion

Answer 13

movement of substances across a semipermeable membrane with the concentration gradient; this process does not require energy

Question 14

pharmacodynamics

Answer 14

the study of the interactions between the chemical components of living systems and the foreign chemicals, including drugs, that enter living organisms; the way a drug affects a body

Question 15

pharmacogenomics

Answer 15

the study of genetically determined variations in the response to drugs

Question 16

pharmacokinetics

Answer 16

the way a medication travels through the body, including absorption, distribution, biotransformation, and excretion; how the body acts on the drug

Question 17

placebo effect

Answer 17

documented effect of the mind on drug therapy; if a person perceives that a drug will be effective, the drug is much more likely to actually be effective

Question 18

receptor sites

Answer 18

specific areas on cell membranes that react with certain chemicals to cause an effect within the cell

Question 19

selective toxicity

Answer 19

property of a chemotherapeutic agent that affects only systems found in foreign cells without affecting healthy human cells (e.g., specific antibiotics can affect certain proteins or enzyme systems used by bacteria but not those used by human cells)

Question 20

therapeutic index

Answer 20

a ratio comparing the blood concentration at which a drug becomes toxic with the concentration at which the drug is effective