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.
Barium is a soft metal belonging to the alkaline earth metals group. It is silvery-white and oxidizes very easily.Its chemical composition resembles calcium [See Periodic Table of the Elements ]. Barium is generally kept under an oxygen-free liquid such as petroleum.It can be decomposed after exposure to water or air.arium is a soft metal belonging to the alkaline earth metals group. It is silvery-white and oxidizes very easily.