Biology Circulation / Transport ETEA 2023 Retake
PMDC Verified Question 23 of 54
The sinoatrial node is located in the ____ wall of the right atrium.
A
Lower dorsal
B
Upper dorsal
C
On the interatrial septum
D
Near the coronary sinus
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Upper dorsal
Concept:

The anatomical placement of the SA node ensures that the electrical signal sweeps downwards across the atria.

Formula:

None

Solution:

  • The Sinoatrial (SA) node is a cluster of specialized pacemaker cells.


  • It is situated in the upper dorsal (superior-posterior) wall of the right atrium, precisely near the opening of the superior vena cava.


  • This high position allows the depolarization wave to efficiently travel downward toward the AV node.


Why other options are incorrect:

  • Near the coronary sinus / lower dorsal: This is the location of the Atrioventricular (AV) node, not the SA node.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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