Related Experiment Video
Updated: May 2, 2026
11:46
Urinary Bladder Distention Evoked Visceromotor Responses as a Model for Bladder Pain in Mice
Published on: April 27, 2014
17.6K
Rectal reservoir and sensory function studied by graded isobaric distension in normal man
S Akervall1, S Fasth, S Nordgren
1Department of Surgery II, Sahlgrenska sjukhuset, University of Göteborg, Sweden.
Gut
|April 1, 1989
Summary
This study reveals how the rectum expands and senses pressure during distension. It highlights that rectal reflexes and sensory thresholds vary significantly among individuals, impacting rectal compliance.
Area of Science:
- Gastroenterology
- Physiology
- Colorectal Function
Background:
- Understanding rectal compliance and sensory feedback is crucial for diagnosing defecation disorders.
- The dynamic response of the rectum to distension influences its reservoir function.
Purpose of the Study:
- To investigate rectal expansion and sensory function under graded isobaric rectal distension.
- To determine pressure thresholds for rectal filling, urge to defecate, and rectoanal reflexes.
Main Methods:
- 36 healthy volunteers underwent rectal distension (5-60 cm H2O).
- Simultaneous recording of anal pressure and external anal sphincter electromyography (EMG).
Main Results:
- Rectal distension induced reflex contractions and gradual volume increase.
- Pressure threshold for rectal filling was 12 cm H2O, coinciding with rectoanal inhibition.
- Urge to defecate occurred at 28 cm H2O, near maximal rectal contraction and external anal sphincter reflex thresholds.
- Significant interindividual variation in rectal compliance was observed.
Conclusions:
- The dynamic rectal response to distension demonstrates a graded reflex adjustment suitable for a reservoir function.
- Rectal compliance varies widely in healthy individuals.
- Sensory and reflex thresholds show relative consistency in volume but variation in pressure.
