Food intake in the nematode Caenorhabditis elegans requires two distinct feeding motions, pharyngeal pumping and isthmus peristalsis. Bacteria, the natural food of C. elegans, activate both feeding motions (Croll, 1978; Horvitz et al., 1982; Chiang et al., 2006). The mechanisms by which bacteria activate the feeding motions are largely unknown. To understand the process, we studied how serotoni...

Undisturbed gastrointestinal motility or peristalsis is critical for effective digestion and absorption of our food and its ingredients. Peristaltic waves in the gut are propelled by the circular and longitudinal layers of smooth muscle cells in the different segments of the gastrointestinal tract. The initiation and regulation of peristalsis is a complex process which, secondary to smooth musc...

I t was first shown by Friedl~inder ~ that a decapitated piece of earthworm would perform normal peristalsis, with perfect coordination between the segments, if it were pulled forward over a rough surface. This experiment proved that the brain was not necessary to locomotion but did not dearly decide the question as to whether the impulse to movement was given by sensory stimulation of the inte...

Women suffering from infertility in association with mostly mild endometriosis were subjected to vaginal sonography of uterine peristalsis during the menstrual period, the early, mid- and late follicular phases, and the mid-luteal phase of the menstrual cycle. The data obtained were compared with those of healthy controls. Women with endometriosis displayed a marked uterine hyperperistalsis tha...

Correspondence to: Professor R K Mittal, Section of Gastroenterology 111D, 3350 La Jolla Village Drive, San Diego, California 92161, USA; [email protected] _________________________ T he function of the oesophagus is relatively straightforward—to transport the swallowed food into the stomach. In order to meet this functional need, the design of the oesophagus is simple; a relatively straight mus...

In ureter peristalsis, the orientation of the contracting smooth muscle cells is essential, yet current descriptions of orientation and composition of the smooth muscle layer in human as well as in rat ureter are inconsistent. The present study aims to improve quantification of smooth muscle orientation in rat ureters as a basis for mechanistic understanding of peristalsis. A crucial step in ou...

Oesophageal manometry revealed 'interrupted peristalsis'--proximal sequential contraction with simultaneous pressure increases in the mid-oesophagus and sequential contraction distally--and abnormally slow distal propagation of peristalsis in seven of a consecutive series of 12 patients with idiopathic diffuse oesophageal spasm (IDOS). These two abnormalities occurred together in six patients. ...

The aquatic oligochaete Lumbriculus variegatus has a segmented, dorsal blood vessel (DBV) that acts as a peristaltic pump to move blood through the animal’s closed circulatory system. We conducted a kinematic study using videography and computational modeling as a first step toward understanding the control of DBV pulsation. Results suggested that pulse rates were highest in the posterior segme...

In this study, for the first time, we consider longitudinal motion of walls during peristalsis in a distensible tube and how affects backward (or retrograde) flow, i.e. peristaltic reflux. Building on analytical model developed by Shapiro et al. ( J. Fluid Mech. , vol. 37, no. 4, 1969, pp. 799–825) based lubrication theory, as two-dimensional infinite sinusoidal wavetrain. We develop an objecti...