WGU D345 Objective Assessment (Latest 2026 Update) Psychopharmacology for Advanced Psychiatric Mental Health Practice Guide| 100% Verified Questions & Answers | Grade A

WGU D345 Objective Assessment (Latest 2026 Update) Psychopharmacology for Advanced Psychiatric Mental Health Practice Guide| 100% Verified Questions & Answers | Grade A QUESTION Steps of Activation for G-Proteins Answer: 1. Neurotransmitter binds GPCR → conformational change. 2. G-protein activated: GDP on α is swapped for GTP. 3. α-subunit (with GTP) + βγ complex separate → both can affect target proteins. 4. Effector activated: o Adenylate cyclase → ↑ or ↓ cAMP. o Phospholipase C → produces IP₃ + DAG → ↑ intracellular Ca²⁺. o Ion channels may open/close indirectly. 5. Signal amplification: one NT binding → many second messengers. 6. Termination: GTP hydrolyzed back to GDP → system resets. QUESTION Clinical Significance of G-Proteins Answer: · Many psychiatric and cardiovascular drugs act on GPCRs (antidepressants, antipsychotics, beta-blockers). · Dysregulation contributes to schizophrenia, depression, anxiety, and addiction. QUESTION Pharmacokinetics (PK) Answer: PK = ADME → Absorb, Distribute, Metabolize, Excrete. Definition What the body does to the drug Absorption - How the drug enters the bloodstream.Affected by: route (oral, IV, IM, subcutaneous), pH, gastric emptying, intestinal motility, first-pass metabolism. Distribution - How drug moves into tissues.Affected by: blood flow, protein binding (albumin), lipid solubility, tissue permeability, body fat. Metabolism (Biotransformation) - How the body breaks down the drug.Affected by: liver enzymes (CYP450), age, genetics, liver disease, enzyme inducers/inhibitors. Excretion - How the drug leaves the body.Affected by: kidney function (GFR, tubular secretion), urine pH, bile/fecal elimination, half-life. QUESTION Pharmacodynamics (PD) Answer: PD = RDE → Receptors, Dose-response, Effect What the drug does to the body Mechanism of action, receptor binding, dose-response Mechanism of Action → How the drug interacts with receptors (agonist, antagonist, partial agonist). Dose-Response Relationship → Efficacy (max effect) vs Potency (dose required for effect). Therapeutic Window → Balance between desired effect and toxicity. Factors affecting PD:Receptor number & sensitivity (upregulation/downregulation).Patient age (infants & elderly respond differently).Tolerance (chronic use reduces effect).Drug interactions (synergism, antagonism).Genetic variations in receptors (pharmacogenomics).Pathological state (e.g., receptor desensitization in depression, altered neurotransmission in schizophrenia). QUESTION Factors affecting PK and PD Answer: Age: neonates (immature metabolism/excretion), elderly (reduced clearance, altered receptor sensitivity). Body composition: fat vs muscle affects distribution. Gender & hormones: can alter metabolism and receptor sensitivity. Genetics: affects CYP450 metabolism (PK) & receptor response (PD). Comorbidities: liver/kidney disease alter PK; neurologic/cardiovascular disease may alter PD. Drug interactions: enzyme induction/inhibition (PK) and synergism/antagonism at receptors (PD). Tolerance & dependence: PK tolerance (increased metabolism) or PD tolerance (receptor downregulation). QUESTION Agonist Answer: A drug that binds to a receptor and activates it fully Mimics the natural ligand → produces full biological response Example: Morphine at μ-opioid receptors (pain relief, euphoria) QUESTION Antagonist Answer: A drug that binds to a receptor but does not activate it Blocks the natural ligand or agonist from binding → no activation Example: Naloxone (blocks opioids at μ-opioid receptor) QUESTION Partial Agonist Answer: Binds to receptor and partially activates it, even at full dose Lower efficacy than a full agonist; can act as antagonist in presence of full agonist Example: Buprenorphine (partial μ-opioid agonist: analgesia with ceiling effect, less risk of respiratory depression) QUESTION Inverse Agonist Answer: Binds to receptor and produces the opposite effect of an agonist Stabilizes receptor in its inactive state, reducing baseline activity Example: Some antihistamines (e.g., loratadine at H1 receptor) are inverse agonists rather than "pure antagonists" QUESTION Depolarization Answer: Cell membrane potential becomes less negative (moves toward +) → neuron "fires" Sodium (Na⁺) channels open → Na⁺ rushes into cell Basis of action potential initiation (e.g., when threshold is reached at axon hillock) QUESTION Repolarization Answer: Return of membrane potential toward resting state (~ -70mV) Potassium (K⁺) channels open → K⁺ flows out of cell Essential for resetting neuron to fire again QUESTION (Hyperpolarization) Answer: (bonus term) Membrane becomes more negative than resting potential Continued K⁺ efflux or Cl⁻ influx Makes neuron less likely to fire (inhibition) QUESTION Neuron Action Potential Terms Mnemonic Answer: Agonist = Go (activates receptor). Antagonist = Against (blocks receptor). Partial Agonist = Part-time (some activation, weaker effect). Inverse Agonist = Inverse (opposite effect, pushes receptor below baseline). Depolarization = Na⁺ In ("influx excites