Practice Essentials. Perinatal asphyxia, more appropriately known as hypoxic-ischemic encephalopathy (HIE), is characterized by clinical and laboratory evidence of acute or subacute brain injury due to asphyxia. The primary causes of this condition are systemic hypoxemia and/or reduced cerebral blood flow (CBF) (see the image below).
Chondrichthyes (/kÉnËdrÉªkÎ¸É¨.iËz/ ; from Greek ÏÎ¿Î½Î´Ï- chondr- 'cartilage', á¼°ÏÎ¸ÏÏ ichthys 'fish') is a class that contains the cartilaginous fishes: they are jawed vertebrates with paired fins, paired nares, scales, a heart with its chambers in series, and skeletons made of cartilage rather than bone.he skeleton is cartilaginous. The notochord, which is present in the young, is gradually replaced by cartilage. Chondrichthyes also lack ribs, so if they leave water, the larger species' own body weight would crush their internal organs long before they would suffocate.
Teleosts, the bony fish, are some of the most abundant vertebrates on the planet with nearly 25,000 living species. In contrast, the chondrichthians represent only about 1,100 species of extant species of.In the past, however, the chondrichthians were much more abundant, according to the fossil record. The skull of a shark is made of only 10 cartilaginous elements while a bony fish skull has about 63 bones. 2  Bony fish have pleural ribs formed from dermal bone and sharks lack these ribs. 3  Unlike bony fish that have a protective bony plate covering their vulnerable gills, the gill slits of a shark are exposed and visible.