Whats the difference between the two?

Which conduction structure is known as the “gatekeeper” between atria and ventricles? Purkinje fibers Bundle of His AV node SA node I picked bundle of his for the answer because the book says that's the "gatekeeper" (pg. 210) and I got it wrong, but google and the feedback says AV node. Wondering which is correct.

Patients with alcoholism are prone to subdural hematomas and GI bleeding because: A) they fall more frequently than sober people B) their blood clotting mechanisms are impaired C) they are at high risk for violent assaults D) alcoholics are immunocompromised

A 24-year-old male is found unresponsive next to an empty bottle of amitriptyline (a tricyclic antidepressant). He is pale, diaphoretic, HR 140, BP 82/50, RR 10 and shallow, SpO₂ 88%. His ECG shows a wide QRS complex with frequent PVCs. What drug should be administered? A) Administer mag sulfate B) Administer sodium bicarb C) Administer calcium chloride D) Administer atropine

A 34‑year‑old patient presents with agitation, dilated pupils, tachycardia, and dry skin. Which toxidrome is most likely? A. Cholinergic B. Anticholinergic C. Sympathomimetic D. Opioid know any examples of these meds?