a drug that competes for the same receptor site as another drug or natural substance and that enhances or stimulates the receptor's functional properties
Agonist
a drug that competes for the same receptor site as another drug or natural substance but dows not produce a physiologic effect by itself
Antagonist
the absence or lack of normal tone or strength
Atony
a group of sympathomimetic amines, including dopamine, norepinephrine, and epinephrine
Catecholamine
a glycoprotein hormone secreted mainly by the kidney; it acts on stem cells of the bone marrow to stimulate red blood cell production
Erythopoietin
abnormally low potassium concentration in the blood
Hypokalemia
abnormally high concentration of urea, creatinine, and other nitrogenous end products of proein and mino acid metabolism in the blood
Uremia
lack of voluntary control over the normal excretion of urine