What is the Leb?

kranium is the upper bone structure of the skull, including everything except the jaw or jaw. Kranium protects the brain and head and promotes facial structures such as eyes and ears, and holds them in the right place to get sensory information most effectively. Animals that have a skull are known together as Kraniates.

kranium is not the only bone, but many. They are connected to the batch, rather than joints that allow very small movement. Human skulls consist of 21 bones and are divided into a neurocranium or cerebral case that surrounds and protects the brain, and spanchnocranium that supports facial structures.

bones in the neocranium are front bone, occipital bone, sphenoid bone, ethmoid bone, two parietal bones and two time bones. In addition to the jaw includes two Maxilly, two palatine bones, two zygomatic bones, two nasal bones, two lachrymal bones, two lower nasal conchae and Vomer's bone. Kranium also contains paranasal cavities that are passage -filled passagesChem communicating with nasal passages inside the nostril.

Amnote, group of animals including mammals, birds and reptiles, can be classified according to the type of skull. Some amnote have bilateral symmetrical holes, called temporary phenestrae, in the time bone of the skull. Animals without temporary fenestrae are classified as anapsids. Turtles are the only living anapsids.

Synapsides have one small low opening on each side of the skull, while diapsids have two holes on each side. Both groups are very diverse. The euryapsids, which are now extinct, had a high opening on each side of the skull. They evolved from diapsids, but lost the lower opening. Mammals are considered to be synapers, although they have to develop no longer temporary phenestrae.

Kranium fish are less well developed than amnote skulls. Most fish skulls have a reduced structure and consist mainly of cartilage rather than bones. LAmprey eels have the easiest Leb of all living cranietes, consisting only of the free structure of cartilage fibers that do not completely say the brain. Fish for rays or actinopterygia have well formed and bony skulls than other fish varieties.