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Quadrate Bone
The quadrate bone is a skull bone in most tetrapods, including amphibians, sauropsids ( reptiles, birds), and early synapsids. In most tetrapods, the quadrate bone connects to the quadratojugal and squamosal bones in the skull, and forms upper part of the jaw joint. The lower jaw articulates at the articular bone, located at the rear end of the lower jaw. The quadrate bone forms the lower jaw articulation in all classes except mammals. Evolutionarily, it is derived from the hindmost part of the primitive cartilaginous upper jaw. Function in reptiles In certain extinct reptiles, the variation and stability of the morphology of the quadrate bone has helped paleontologists in the species-level taxonomy and identification of mosasaur squamates and spinosaurine dinosaurs. In some lizards and dinosaurs, the quadrate is articulated at both ends and movable. In snakes, the quadrate bone has become elongated and very mobile, and contributes greatly to their ability to swallow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skull Anapsida 1
The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent parts: the neurocranium and the facial skeleton, which evolved from the first pharyngeal arch. The skull forms the frontmost portion of the axial skeleton and is a product of cephalization and vesicular enlargement of the brain, with several special senses structures such as the eyes, ears, nose, tongue and, in fish, specialized tactile organs such as barbels near the mouth. The skull is composed of three types of bone: cranial bones, facial bones and ossicles, which is made up of a number of fused flat and irregular bones. The cranial bones are joined at firm fibrous junctions called sutures and contains many foramina, fossae, processes, and sinuses. In zoology, the openings in the skull are called fenestrae, the most prominent of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinosauridae
Spinosauridae (or spinosaurids) is a clade or Family (taxonomy), family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. Spinosaurid fossils have been recovered worldwide, including Africa, Europe, South America, and Asia. Their remains have generally been attributed to the Early Cretaceous, Early to early Late Cretaceous. Spinosaurids were large Bipedalism, bipedal carnivores. Their crocodilian-like skulls were long, low, and narrow, bearing conical teeth with reduced or absent Glossary of dinosaur anatomy#serrations, serrations. The tips of their upper and Glossary of dinosaur anatomy#mandible, lower jaws fanned out into a spoon-shaped structure similar to a Rosette (design), rosette, behind which there was a Glossary of dinosaur anatomy#subnarial gap, notch in the upper jaw that the expanded tip of the lower jaw fit into. The Glossary of dinosaur anatomy#bony nostrils, nostrils of spinosaurids were retracted to a position further back on the head than in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossicles
The ossicles (also called auditory ossicles) are three irregular bones in the middle ear of humans and other mammals, and are among the smallest bones in the human body. Although the term "ossicle" literally means "tiny bone" (from Latin ''ossiculum'') and may refer to any small bone throughout the body, it typically refers specifically to the malleus, incus and stapes ("hammer, anvil, and stirrup") of the middle ear. The auditory ossicles serve as a kinematic chain to transmit and amplify ( intensify) sound vibrations collected from the air by the ear drum to the fluid-filled labyrinth ( cochlea). The absence or pathology of the auditory ossicles would constitute a moderate-to-severe conductive hearing loss. Structure The ossicles are, in order from the eardrum to the inner ear (from superficial to deep): the malleus, incus, and stapes, terms that in Latin are translated as "the hammer, anvil, and stirrup". * The malleus () articulates with the incus through the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columella (auditory System)
In the auditory system, the columella contributes to hearing in amphibians, reptiles and birds. The columella form thin, bony structures in the interior of the skull and serve the purpose of transmitting sounds from the eardrum. It is an evolutionary Homology (biology), homolog of the stapes, one of the Evolution of mammalian auditory ossicles, auditory ossicles in mammals. In many species, the extracolumella is a cartilaginous structure that grows in association with the columella. During development, the columella is derived from the dorsal end of the Pharyngeal arch, hyoid arch. Evolution The evolution of the columella is closely related to the evolution of the Temporomandibular joint, jaw joint. It is an ancestral homolog of the stapes, and is derived from the Hyomandibula, hyomandibular bone of fishes. As the columella is derived from the hyomandibula, many of its functional relationships remain the same. The columella resides in the air-filled tympanic cavity of the middl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, ''regardless'' of current functional differences. Evolutionary biology explains homologous structures as retained heredity from a common descent, common ancestor after having been subjected to adaptation (biology), adaptive modifications for different purposes as the result of natural selection. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this from Aristotle's biology onwards, and it was explicitly analysed by Pierre Belon in 1555. A common example of homologous structures is the forelimbs of vertebrates, where the bat wing development, wings of bats and origin of avian flight, birds, the arms of primates, the front flipper (anatomy), flippers of whales, and the forelegs of quadrupedalis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stapes
The ''stapes'' or stirrup is a bone in the middle ear of humans and other tetrapods which is involved in the conduction of sound vibrations to the inner ear. This bone is connected to the oval window by its annular ligament, which allows the footplate (or base) to transmit sound energy through the oval window into the inner ear. The ''stapes'' is the smallest and lightest bone in the human body, and is so-called because of its resemblance to a stirrup (). Structure The ''stapes'' is the third bone of the three ossicles in the middle ear and the smallest in the human body. It measures roughly , greater along the head-base span. It rests on the oval window, to which it is connected by an annular ligament and articulates with the ''incus'', or anvil through the incudostapedial joint. They are connected by anterior and posterior limbs (). Development The ''stapes'' develops from the second pharyngeal arch during the sixth to eighth week of embryological life. The central ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incus
The ''incus'' (: incudes) or anvil in the ear is one of three small bones (ossicles) in the middle ear. The incus receives vibrations from the malleus, to which it is connected laterally, and transmits these to the stapes medially. The incus is named for its resemblance to an anvil (). Structure The incus is the second of three ossicles, very small bones in the middle ear which act to transmit sound. It is shaped like an anvil, and has a long and short crus extending from the body, which articulates with the malleus. The short crus attaches to the posterior ligament of the incus. The long crus articulates with the stapes at the lenticular process. The superior ligament of the incus attaches at the body of the incus to the roof of the tympanic cavity. The incus is Homology (biology), homologous to the quadrate bone found in other tetrapods. Function Vibrations in the middle ear are received via the tympanic membrane. The malleus, resting on the membrane, conveys vibrations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malleus
The ''malleus'', or hammer, is a hammer-shaped small bone or ossicle of the middle ear. It connects with the incus, and is attached to the inner surface of the eardrum. The word is Latin for 'hammer' or 'mallet'. It transmits the sound vibrations from the eardrum to the ''incus'' (anvil). Structure The malleus is a bone situated in the middle ear. It is the first of the three ossicles, and attached to the eardrum (tympanic membrane). The head of the malleus is the large protruding section, which attaches to the incus. The head connects to the neck of malleus. The bone continues as the handle (or manubrium) of malleus, which connects to the tympanic membrane. Between the neck and handle of the malleus, lateral and anterior processes emerge from the bone. The bone is oriented so that the head is superior and the handle is inferior. Development Embryologically, the malleus is derived from the first pharyngeal arch along with the ''incus''. In humans it grows from Meckel's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Ear
The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear). The mammalian middle ear contains three ossicles (malleus, incus, and stapes), which transfer the vibrations of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear is also known as the tympanic cavity and is surrounded by the tympanic part of the temporal bone. The auditory tube (also known as the Eustachian tube or the pharyngotympanic tube) joins the tympanic cavity with the nasal cavity ( nasopharynx), allowing pressure to equalize between the middle ear and throat. The primary function of the middle ear is to efficiently transfer acoustic energy from compression waves in air to fluid–membrane waves within the cochlea. Structure Ossicles The middle ear contains three tiny bones known as the ossicles: '' malleus'', ''incus'', and '' stapes''. The ossicles were given their Latin names f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals
A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which their ancestors diverged in the Carboniferous Period over 300 million years ago. Around 6,640 extant species of mammals have been described and divided into 27 orders. The study of mammals is called mammalogy. The largest orders of mammals, by number of species, are the rodents, bats, and eulipotyphlans (including hedgehogs, moles and shrews). The next three are the primates (including humans, monkeys and lemurs), the even-toed ungulates (including pigs, camels, and whales), and the Carnivora (including cats, dogs, and seals). Mammals are the only living members of Synapsida; this clade, together with Sauropsida (reptiles and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Python Daudin, 1803
Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (programming language), a widely used high-level programming language * Python, a native code compiler for CMU Common Lisp * Python, the internal project name for the PERQ 3 computer workstation People * Python of Aenus (4th-century BCE), student of Plato * Python (painter) (ca. 360–320 BCE), vase painter in Poseidonia * Python of Byzantium (4th-century BCE), orator, diplomat of Philip II of Macedon * Python of Catana Python of Catana, Magna Graecia, was a dramatic poet of the time of Alexander the Great, Alexander, whom he accompanied into Asia, and whose army he entertained with a satyric drama, called ''Agen ()'' when they were celebrating the Dionysia on t ..., poet who accompanied Alexander the Great * Python Anghelo (1954–201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skull
The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent parts: the neurocranium and the facial skeleton, which evolved from the first pharyngeal arch. The skull forms the frontmost portion of the axial skeleton and is a product of cephalization and vesicular enlargement of the brain, with several special senses structures such as the eyes, ears, nose, tongue and, in fish, specialized tactile organs such as barbels near the mouth. The skull is composed of three types of bone: cranial bones, facial bones and ossicles, which is made up of a number of fused flat and irregular bones. The cranial bones are joined at firm fibrous junctions called sutures and contains many foramina, fossae, processes, and sinuses. In zoology, the openings in the skull are called fenestrae, the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
