The digestive tract of vertebrates requires a large surface area in order to absorb nutrients from a high protein diet. While most vertebrates, like humans, accomplish this by having long intestines covered in villi, the cartilaginous fish (sharks, skates and rays) have a unique spiral valve intestine enclosed within a short stretch of intestine. Using microCT-scanned images of developing embryos and the software programs CTan and CTvol, we analyzed differences in the pitch, helical and tangential angles of the spiral at different stages of its development in little skate Leucoraja erinacea embryos. The distance between the turns in the spiral (pitch) decreases along the anterior to posterior axis of the intestine. The helical angles are very sharp at the anterior position, and alternate between decreasing and increasing intensities depending on the stage of the spiral. The tangential angles complement the helical angles; they are initially low at the anterior position, and similar to the helical, increase and decrease towards the posterior. The degree of angle variation becomes very pronounced in the older embryo, as the whole spiral begins to curve in at the posterior end. The 3D analysis program Cloudcompare was used to reshape and edit the internal spiral and printed to better visualize the morphology of it. Understanding and characterizing the features of the spiral will help us understand the forces involved in generating the turns that lead to the spiral formation in the skate intestine.
Additional Speakers
Faculty Sponsors