Large Intestine
The large intestine starts from the cecum and the ileocecal valve, which serves as the junction between the small and large intestines. The areas of the large intestine that need to be identified are the cecum, spiral colon, ileocecal valve, tranverse, descending, and sigmoid colon, and the rectum.
In the photo to the top, the Cecum is circled in red. the Cecum in our pig was not fully green (more grey), like the rest of the colon, but from observing other fetal pigs, it is commonly green.
to Expose the ileocecal valve, we flipped this over. The photo to the bottom still shows circled the cecum, now view of its back. you can see that near the blue arrow, the food is traveling down a valve like structure, entering the cecum. therefore, the blue arrow is pointing at the ileocecal valve, which controls the movement of food from the small intestines to the large intestines. |
In this picture, the blunt probe is pointing to the spiral colon.
It is named for its spiral shape, and is easily spotted due to the unique shape. The spiral colon is the similar to the ascending colon in humans. The transverse colon and descending colon are the third and fourth parts of the large intestine, which undergo peristalsis to expel any leftover water and nutrients that were unable to be absorbed. |
The below picture shows mostly the transverse colon section of the large intestine (where red arrow points to). in the pigs, the transverse colon is very short, and exists to connect the spiral colon to the decending colon, which is shown by the blue arrow.
Sigmoid Colon and Rectum
The Sigmoid colon looks like a bump in the descending colon. it functions to connect the descending colon to the rectum and is a short transverse intestine. the photo beneath this box will show the sigmoid colon.
The Rectum is a short vertical intestine, that fills up with feces to be exerted out of the body through the anus. it is a chamber for feces before defecation. it is the part of the vertical line of colon after the sigmoid colon. this is pointed out by the red line in the picture to the left.
The Rectum is a short vertical intestine, that fills up with feces to be exerted out of the body through the anus. it is a chamber for feces before defecation. it is the part of the vertical line of colon after the sigmoid colon. this is pointed out by the red line in the picture to the left.
Anus
The anus' function is to control the expulsion of feces, or defecation, after digestion. It has two muscle layers, an external sphincter with skeletal muscle (voluntarily controlled) and an internal sphincter of smooth muscle (involuntarily controlled). It is fairly easy to find, just look at the butt of the pig. if you want to reveal the inner smooth muscle, you need to peel off the outer skin and sphincter (which we did not do)
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