instance_of dysostosis
A dysostosis is a disorder of the development of ___MASK95___ , in particular affecting ossification . Examples include craniofacial dysostosis , Klippel - Feil syndrome , and Rubinstein - Taybi syndrome . It is one of the two categories of constitutional disorders of ___MASK95___ ( the other being osteochondrodysplasia ) . When the disorder involves the joint between two bones , the term synostosis is often used . A ___MASK49___ is a naturally occurring ___MASK3___ compound , usually of crystalline form and abiogenic in origin . A ___MASK49___ has one specific ___MASK3___ ___MASK51___ , whereas a rock can be an aggregate of different minerals or mineraloids . The study of minerals is called mineralogy . Intramembranous ossification is one of the ___MASK40___ essential processes during fetal development of the gnathostome ( excluding chondrichthyans such as sharks ) skeletal ___MASK18___ by which rudimentary ___MASK95___ tissue is created . Intramembranous ossification is also an essential process during the natural healing of ___MASK95___ fractures and the rudimentary formation of bones of the head . Unlike endochondral ossification , which is the other process by which ___MASK95___ tissue is created during fetal development , cartilage is not present during intramembranous ossification . Osteoblasts ( from the Greek combining forms for " ___MASK95___ ",  -, " osteo -" and  , " blastan " " germinate ") are cells with a single ___MASK62___ that synthesize ___MASK95___ . However , in the process of ___MASK95___ formation , osteoblasts function in groups of connected cells . Individual cells cannot make ___MASK95___ . A group of organized osteoblasts together with the ___MASK95___ made by a unit of cells is usually called the osteon . Vertebrates comprise all ___MASK52___ of animals within the subphylum Vertebrata ( chordates with backbones ). Vertebrates represent the overwhelming majority of the phylum Chordata , with currently about 64 , 000 ___MASK52___ described . Vertebrates include the jawless fish and the jawed vertebrates , which include the cartilaginous fish ( sharks and rays ) and the bony fish . Endochondral ossification is one of the ___MASK40___ essential processes during fetal development of the mammalian skeletal ___MASK18___ by which ___MASK95___ tissue is created . Unlike intramembranous ossification , which is the other process by which ___MASK95___ tissue is created , cartilage is present during endochondral ossification . Endochondral ossification is also an essential process during the rudimentary formation of long bones , the growth of the length of long bones , and the natural healing of ___MASK95___ fractures . Cartilage is a resilient and smooth elastic ___MASK6___ , rubber - like padding that covers and protects the ends of long bones at the joints , and is a structural component of the ___MASK15___ cage , the ear , the nose , the bronchial tubes , the intervertebral discs , and many other body components . It is not as hard and rigid as ___MASK95___ , but it is stiffer and less flexible than muscle . ___MASK95___ remodeling ( or ___MASK95___ metabolism ) is a lifelong process where mature ___MASK95___ tissue is removed from the skeleton ( a process called " ___MASK95___ resorption ") and new ___MASK95___ tissue is formed ( a process called " ossification " or " new ___MASK95___ formation "). These processes also control the reshaping or replacement of ___MASK95___ following injuries like fractures but also micro - damage , which occurs during normal activity . Remodeling responds also to functional demands of the mechanical loading . The ___MASK88___ ( from Greek  , " skeletós " " dried up ") is the body part that forms the supporting structure of an ___MASK65___ . There are several different skeletal types : the exoskeleton , which is the stable outer shell of an ___MASK65___ , the endoskeleton , which forms the support structure inside the body , the hydroskeleton , and the cytoskeleton . A ___MASK95___ is a rigid organ that constitutes part of the vertebrate skeleton . Bones support and protect the various organs of the body , produce red and white blood cells , store minerals , provide structure and support for the body , and enable mobility . Bones come in a ___MASK31___ of shapes and sizes and have a complex internal and external structure . They are lightweight yet strong and hard , and serve multiple functions . White blood cells ( WBCs ), also called leukocytes or leucocytes , are the cells of the immune ___MASK18___ that are involved in protecting the body against both infectious ___MASK32___ and foreign invaders . All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells . Leukocytes are found throughout the body , including the blood and lymphatic ___MASK18___ . Ossification ( or osteogenesis ) in ___MASK95___ remodeling is the process of laying down new ___MASK95___ material by cells called osteoblasts . It is synonymous with ___MASK95___ tissue formation . There are two processes resulting in the formation of normal , healthy ___MASK95___ tissue : Intramembranous ossification is the direct laying down of ___MASK95___ into the primitive connective tissue ( mesenchyme ), while endochondral ossification involves cartilage as a precursor . In fracture healing , endochondral osteogenesis is the most commonly occurring process , for example in fractures of long bones treated by plaster of Paris , whereas fractures treated by open reduction and internal fixation with metal plates , screws , pins , rods and nails ___MASK89___ heal by intramembranous osteogenesis . Mesenchyme is a type of ___MASK6___ characterized by loosely associated cells that lack polarity and are surrounded by a large extracellular ___MASK20___ .