Describe the function and components of the mucosal barrier of the stomach. Protects the stomach from autodigestion Components Thick coating of bicarbonate-rich mucus Tight junctions of the epithelial cells Plasma membrane of gastric glands are impermeable to HCl.
World Range & Habitat. Sea lampreys, Petromyzon marinus, are found only in the Mediterranean and North Atlantic, in the coastal seas off the North East USA, Nova Scotia, southern Greenland, the UK, Ireland and Scandinavia. They are also found in the Great Lakes and enters inland freshwater rivers and streams to breed.
Abstract. Hagfish and lampreys are the only living representatives of the jawless vertebrates (agnathans), and compared with jawed vertebrates (gnathostomes), they provide insight into the embryology, genomics, and body plan of the ancestral vertebrate.e did not find any nucleotide substitutions in the mature sequence of any vertebrate miRNA that is shared between gnathostomes and lampreys to the exclusion of hagfish (or between hagfish and gnathostomes to the exclusion of lamprey).