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.
Bony fishes can swim forward and backward.   Gills:   Both cartilaginous and bony fish have gill slits but the bony fish also have gill covers (an operculum).   Reproduction:   In the Chondrichthyes the males have claspers which assist in copulation. Fertilisation is internal-almost unique among fish. Scales:   Cartilaginous fish have large scales called placoid scales. These have a bone like base embedded in the skin and a backward projecting enamel covered dentine spine. The whole thing has a central pulp cavity (rather like the structure of teeth). The epidermis and dermis form placoid scales.