Search results
Results from the WOW.Com Content Network
In practice, fish anatomy and fish physiology complement each other, the former dealing with the structure of a fish, its organs or component parts and how they are put together, such as might be observed on the dissecting table or under the microscope, and the latter dealing with how those components function together in living fish. The ...
Fish fall into two main groups: fish with bony internal skeletons and fish with cartilaginous internal skeletons. Fish anatomy and physiology generally includes a two-chambered heart, eyes adapted to seeing underwater, and a skin protected by scales and mucous. They typically breathe by extracting oxygen from water through gills.
In humans, cervical vertebrae are the smallest of the true vertebrae and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process, through which the vertebral artery, vertebral veins, and inferior cervical ganglion pass. The remainder of this article focuses upon ...
Chondrichthyes (/ k ɒ n ˈ d r ɪ k θ i iː z /; from Ancient Greek χόνδρος (khóndros) 'cartilage' and ἰχθύς (ikhthús) 'fish') is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage.
The cleithrum (pl.: cleithra) is a membrane bone which first appears as part of the skeleton in primitive bony fish, where it runs vertically along the scapula. [1] Its name is derived from Greek κλειθρον = " key (lock) ", by analogy with " clavicle " from Latin clavicula = "little key".
Fish bone is any bony tissue in a fish, although in common usage the term refers specifically to delicate parts of the non-vertebral skeleton of such as ribs, fin spines and intramuscular bones. Not all fish have fish bones in this sense; for instance, eels and anglerfish do not possess bones other than the cranium and the vertebrae.
All vertebrate jaws, including the human jaw, evolved from early fish jaws. The appearance of the early vertebrate jaw has been described as "perhaps the most profound and radical evolutionary step in the vertebrate history". [4] [5] Fish without jaws had more difficulty surviving than fish with jaws, and most jawless fish became extinct.
The skeleton of the head of a perch Parts of a pike's head. 1: liver, 2: gill arch, 3: palate with sharp teeth, 4: in the middle a heart, 5: fragment of spinal cord, 6: brain, 7: spherical lens, 8: scale. Fish heads, either separated or still attached to the rest of the fish, are sometimes used in culinary dishes, or boiled for fish stock.