Apex Final 1 | 1960 Questions| With Complete Solutions 100% Verified Graded A+ (2024-2025

)) Types of nicotinic receptors - ANSWER--Nn: presynaptic (nerve cell) Nm: postsynaptic (muscle cell) Postsynaptic Nicotinic Receptors - ANSWER--Pentameric: 2 alpha, 1 beta, 1 delta, 1 epsilon subunits Each alpha subunit binds 1 ACh. Which subunits need to be occupied to open the nicotinic receptor - ANSWER--alpha and alpha the channel opens when both are occupied and Na+ & Ca++ flow in, K+ flows out. Acetylcholinesterase - ANSWER--Positioned around Nn and Nm nicotinic receptors. Hydrolyzes ACh almost immediately after binding. Ensure muscle contractions are discreet and not sustained. Extrajunctional receptors - ANSWER--Pathologic variant of ACh (nicotinic) receptors that have become denervated -resemble receptors present in fetal development = these are replaced by the adult subtype once innervation takes place -proliferate after muscle injury/disease/burns -the alpha 7 receptor is depolarized by both succ and its metabolite choline (choline makes a significant contribution to hyperkalemia) Presence of extrajunctional receptors predisposes patients to what? - ANSWER--Hyperkalemia Extrajuctional receptors reaction to NDNMB's - ANSWER--increased resistance = need to use higher doses Extrajunctional receptors reaction to succ - ANSWER--More sensitive - receptors stay open longer (more K+ leak) = this is why succ can cause hyperkalemia) 2 types of extrajunctional receptors (subunit makeup) - ANSWER--1-