The beak, bill, and/or rostrum is an external anatomical structure of birds that is used for eating and for preening, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young. The terms beak and rostrum are also used to refer to a similar mouth part in some ornithischians, pterosaurs, turtles, cetaceans, dicynodonts, anuran tadpoles, sirens, pufferfishes, billfishes and cephalopods.
Although beaks vary significantly in size, shape, color and texture, they share a similar underlying structure. Two bony projections—the upper and lower mandibles—are covered with a thin keratinized layer of epidermis known as the rhamphotheca. In most species, two holes known as nares lead to the respiratory system.Beak (disambiguation)
A beak is an anatomical structure of birds, which serves as the mouth and jaws.
Beak may also refer to:
Beak, a type of molding
Barnell Bohusk, a Marvel Comics character formerly known as Beak
Beak, a Beanie Buddy kiwi bird
Beak (botany), a pointed projection on various parts of plants
Beak, an old-fashioned slang term for the headmaster of a school or a magistrate
Beak, slang term for the drug cocaine
Beak (band), a music group formed by Geoff Barrow, Billy Fuller, and Matt Williams
Beak Island, in the Prince Gustav Channel
A member of the teaching staff at Charterhouse School or Harrow School
Beak (bivalve), the oldest point of a shell of a bivalve mollusc
The neuraxis or sometimes neuroaxis is the axis of the central nervous system. It denotes the direction in which the central nervous system lies. During embryological development, the neuraxis is bent by various flexures, contributing to the mature structure of the brain and spinal cord.
Embryonic development can help in understanding the structure of the adult brain because it establishes a framework on which more complex structures can be built. First, the neural tube establishes the anterior–posterior dimension of the nervous system, which is called the neuraxis. The embryonic nervous system in mammals can be said to have a standard arrangement. Humans (and other primates, to some degree) make this complicated by standing up and walking on two legs.
The anterior–posterior dimension of the neuraxis overlays the superior–inferior dimension of the body. However, there is a major curve between the brain stem and forebrain, which is called the cephalic flexure. Because of this, the neuraxis starts in an inferior position—the end of the spinal cord—and ends in an anterior position, the front of the cerebrum. This may be confusing, and can be illustrated when looking at a four-legged animal standing up on two legs. Without the flexure in the brain stem, and at the top of the neck, that animal would be looking straight up instead of straight in front.Rostrum
Rostrum may refer to:
Any kind of a platform for a speaker:
Australian Rostrum, an association of Australian public speaking clubs
Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects
Rostrum (ship), a form of bow on naval ships
Rostrum of corpus callosum, a commissural fiber
Rostrum Records, an American record label
The Rostrum, the official monthly magazine of the National Forensic League
International Rostrum of Composers