Echinodermata, Hemichordata and Xenoturbellida form the clade Ambulacraria. The present phylum Priapulida also has a deuterostomic development, despite being otherwise placed within the protostomes. In both deuterostomes and protostomes, a zygote first develops into a hollow ball of cells, called a blastula.In deuterostomes, the early divisions occur parallel or perpendicular to the polar axis. This is called radial cleavage, and also occurs in certain protostomes, such as the lophophorates.chinodermata, Hemichordata and Xenoturbellida form the clade Ambulacraria. The present phylum Priapulida also has a deuterostomic development, despite being otherwise placed within the protostomes. In both deuterostomes and protostomes, a zygote first develops into a hollow ball of cells, called a blastula.
In this test you drink some barium liquid. The barium liquid is often fruit-flavoured so it is pleasant to drink. You stand in front of an X-ray machine whilst X-ray pictures are taken as you swallow. This test aims to look for problems in the gullet (oesophagus).
Barium meal. This is similar to a barium swallow (above) but aims to look for problems in the stomach and duodenum such as ulcers, polyps, tumours, etc. You drink some barium liquid, but you then lie on a couch whilst X-ray pictures are taken over your abdomen. It may take a little longer to do than a barium swallow.his test is similar to a barium follow through. However, instead of drinking the barium liquid, a thin tube is passed down your gullet (oesophagus), through the stomach and into the first part of the small intestine.