Defecation Motor Program
Defecation Motor Program - Related Videos
11:49
An In Vitro Preparation for Eliciting and Recording Feeding Motor Programs with Physiological Movements in Aplysia californica
0 Views •
Cited by 24 •
2012
We describe a technique to extracellularly record and stimulate from nerves, muscles, and individual identified neurons in vitro while eliciting and observing different types of feeding behaviors in the feeding apparatus of Aplysia.
01:26
Feces Formation and Defecation
0 Views •
2025
After spending 3 to 10 hours in the large intestine, chyme loses a lot of water and becomes feces, the final product of digestion. Feces consist of undigested dietary fiber such as cellulose, mucus, sloughed-off epithelial cells, and microbes. The descending and sigmoid colon stores feces and uses haustral contractions to dry it out but retains enough water to give it a semi-solid texture. The mass peristalsis then pushes the feces into the rectum, which stretches the rectal walls to activate...
14:55
Methods to Quantify Pharmacologically Induced Alterations in Motor Function in Human Incomplete SCI
0 Views •
Cited by 17 •
2011
This video demonstrates modulation of reflex activity, volitional strength and ambulation through clinical and quantitative assessments in individuals with motor incomplete SCI as a result of acute oral administration of a serotonin reuptake inhibitor (SSRI).
08:45
An Introduction to Motor Control
0 Views •
2023
Motor control involves integration and processing of sensory information by our nervous system, followed by a response through our skeletal system to perform a voluntary or involuntary action. It is vital to understand how our neuroskeletal system controls motor behavior in order to evaluate injuries pertaining to general movement, reflexes, and coordination. An improved understanding of motor control will help behavioral neuroscientists in developing useful tools to treat motor disorders, such...
09:29
DC Motors
0 Views •
2023
Source: Ali Bazzi, Department of Electrical Engineering, University of Connecticut, Storrs, CT. The DC machine operates with DC currents and voltages as opposed to an AC machine, which requires AC currents and voltages. DC machines were the first to be invented and utilize two magnetic fields that are controlled by DC currents. The same machine can be easily reconfigured to be a motor or generator if appropriate field excitation is available, since the DC machine has two fields termed field...
FAQs
As fecal material distends the rectum, sensory pathways detect the change and activate spinal parasympathetic circuits. These neural responses promote rectal contraction and prepare the anal outlet by relaxing the internal anal sphincter. The sequence links a mechanical stimulus to coordinated propulsion, making sensory signaling an important starting point for effective elimination.
The internal anal sphincter responds to the motor program by relaxing, while the external anal sphincter remains under voluntary control. This difference allows the body to distinguish automatic outlet preparation from conscious timing. Effective elimination therefore depends not only on rectal propulsion, but also on appropriate voluntary relaxation of the external sphincter.
Pelvic-floor relaxation helps open the outlet after rectal contraction and internal sphincter relaxation have prepared the anal canal. Voluntary control permits this step to occur when elimination is appropriate rather than immediately after rectal distension. If relaxation is poorly coordinated, stool movement may become difficult despite activation of the upstream motor sequence.
Continence depends on retaining voluntary control over the external anal sphincter and pelvic floor while sensory and autonomic signals respond to rectal filling. Elimination requires the opposite timing: coordinated relaxation alongside rectal contraction. This balance explains why disruption of neural or muscular coordination can present as either obstructed defecation or fecal incontinence.
Clinicians can use the expected sequence as a framework for identifying where evacuation fails, including rectal contraction, internal sphincter relaxation, external sphincter relaxation, or pelvic-floor coordination. This approach is relevant when assessing constipation and obstructed defecation because symptoms may reflect impaired coordination rather than inadequate fecal propulsion alone.
The coordinated neural and muscular events of defecation provide the physiological context for anorectal manometry. By studying anorectal function, clinicians can relate symptoms to the behavior of the rectum and anal sphincters during the programmed sequence. The assessment can therefore contribute to evaluation of constipation, fecal incontinence, and other disorders of bowel control.
Understanding the sequence supports pelvic-floor rehabilitation by identifying the importance of coordinated voluntary relaxation rather than focusing only on stool movement. It also provides a framework for studying neurogenic bowel disorders, gastrointestinal motility, and autonomic control. These applications connect bedside evaluation with research into how neural circuits and anorectal muscles regulate bowel regularity and continence.