Contraction and distension during stripes

Left, simultaneous video from two cameras of the same small intestine, corresponding to the two boxed sections of the DMap in Figure 5. Right, corresponding DMaps: the moving green line indicates the temporal position in the video. Vertical green scale bars are 1 cm and horizontal green scale bar is 5 s. During a stripe contracting portions of the intestine force fluid into non-contracting portions, causing them to distend. Upper (proximal) video: dark-light (DL) banded stripes correspond to active contraction followed by distension. Notice the v-wave mid-way through the video. Lower (distal) video: light-dark (LD) banded stripes result purely from passive movement of luminal fluid. The proximal, actively contracting segment forces fluid down into the distal segment, so distending it and creating a light band. As the proximal segment then relaxes, the distal fluid reverses course as it is sucked upward and this suction creates a dark band that follows the light. The downward, then upward movement of fluid with each stripe can be tracked by shed mucosa (moving white material) in the lumen. [CD-1, Trendelenburg, 80 M carbenoxolone].