Sympathetic post-ganglionic transmission

Question

BlackTom AI · Accepted Answer

Question restatement: The topic is sympathetic post-ganglionic transmission, and we must evaluate which description correctly characterizes the signalling pathways involved for adrenergic receptors.
Option a: 'Acts only through the PLC-beta signalling pathway' would imply that all sympathetic post-ganglionic transmission uses PLC-beta exclusively. This is misleading because beta adrenergic receptors typically couple to Gs proteins that stimulate adenylate cyclase and increase cAMP, not PLC-beta, so this option ignores the well-established cAMP pathway for beta receptors.
Option b: 'Acts only through the Adenylate cyclase / cAMP signalling pathway' would ignore the fact that alpha-adrenergic receptors commonly couple to Gq proteins that activate PLC-beta and generate inositol trisphosphate (IP3) and diacylglycerol (DAG). Since alpha receptors can signal through PLC-beta, a statement asserting exclusivity to cAMP would be incomplete.
Option c: 'Involves beta adrenergic receptors acting through the Adenylate cyclase / cAMP signalling pathway and alpha adrenergic receptors acting through or the PLC-beta pathway' presents a mixed model: beta receptors signaling via AC/cAMP and alpha receptors signaling via PLC-beta (the Gq pathway). This aligns with the canonical dichotomy where beta receptors predominantly use the cAMP route, while alpha-1 receptors often engage PLC-beta signaling. The wording also allows for the alpha pathway to be active via PLC-beta, which is consistent with known alpha-1 signaling.
Option d: 'Involves alpha adrenergic receptors acting through the Adenylate cyclase / cAMP signalling pathway and beta adrenergic receptors acting through or the PLC-beta pathway' flips the typical coupling: alpha receptors are not predominantly linked to AC/cAMP signaling; they are primarily associated with PLC-beta via Gq. Similarly, beta receptors are not primarily coupled to PLC-beta. Hence this option misattributes the main pathways to each receptor type.
Option e: 'Involves alpha or beta adrenergic receptors that act either through the Adenylate cyclase / cAMP signalling pathway or the PLC-beta pathway' suggests that either receptor type can independently choose between pathways in all cases. In physiology, while there is diversity, the typical associations are more specific (beta with cAMP, alpha with PLC-beta). This option is overly vague and does not reflect the common, receptor-specific coupling patterns, making it an inaccurate generalization.
Overall, option c accurately reflects the complementary signalling roles of beta receptors via adenylate cyclase / cAMP and alpha receptors via PLC-beta, while the other choices correspond to oversimplifications or misattributions of receptor–pathway couplings.

Sympathetic post-ganglionic transmissionSingle choice

Similar Questions

Question at position 62 True or False: Stimulation of alpha-1 receptors on the heart will result in an increased heart rate.TrueFalse

Stimulation of beta-1 receptors on cardiac muscle cells will result in:

True or false: Stimulation of alpha receptors will cause vasoconstriction in arterioles.

The alpha and beta receptors belong to which division of the ANS?

Sympathetic nervous system postganglionic fibres synapse on:

Delivering adrenaline via an 'Epi Pen' during anaphylactic shock has which of the following benefits?

Adrenaline acts on:

Question at position 1 A firm competing in a single-product market in a single geographic location does not need a corporate-level strategy regarding product diversity or an international strategy to deal with geographic diversity.TrueFalse

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler