Biology Circulation / Transport UHS 2022
PMDC Verified Question 32 of 54
Flow of blood in the capillaries is adjusted by:
A
Heart directly
B
Pre-capillary sphincters
C
Meta-arteriole
D
Valves
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Pre-capillary sphincters
Concept:

Microcirculation must be finely tuned to match the metabolic demands of specific tissues at any given moment.

Formula:

None

Solution:

  • At the junction between metarterioles and true capillaries, there are rings of smooth muscle known as pre-capillary sphincters.


  • By contracting or relaxing, these sphincters act as valves to restrict or permit blood flow into the capillary beds based on local chemical signals.


Why other options are incorrect:

  • The heart provides systemic pressure but cannot dictate localized flow to individual capillary beds. Vein valves only prevent backflow.

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.

Previous Question All Circulation / Transport MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App