Protostomia (from Greek meaning mouth first) are a clade of animals. Together with the deuterostomes and other phyla, they make up the Bilateria, mostly comprising animals with bilateral symmetry and three germ layers.The major distinctions between deuterostomes and protostomes are found in embryonic development.In animals at least as complex as earthworms, the embryo forms a dent on one side, the blastopore, which deepens to become the archenteron, the first phase in the growth of the gut.ogether with the deuterostomes and other phyla, they make up the Bilateria, mostly comprising animals with bilateral symmetry and three germ layers. The major distinctions between deuterostomes and protostomes are found in embryonic development.
A barium enema, or lower gastrointestinal (GI) examination, is an X-ray examination of the large intestine (colon and rectum). The test is used to help diagnose diseases and other problems that affect the large intestine. To make the intestine visible on an X-ray picture, the colon is filled with a contrast material containing barium. This is done by pouring the contrast material through a tube inserted into the anus.
A barium swallow is a diagnostic test that involves a series of X-rays of the esophagus, stomach, and duodenum during and after drinking a barium solution. The duodenum is the first part of the small intestine; and the esophagus, stomach, and duodenum are collectively called the upper gastrointestinal (GI) tract or upper digestive system. You may also hear doctors refer to a barium swallow as an upper GI series or a barium meal.