Mature osteoblasts that have become embedded in the BONE MATRIX. They occupy a small cavity, called lacuna, in the matrix and are connected to adjacent osteocytes via protoplasmic projections called canaliculi.
Bone-forming cells which secrete an EXTRACELLULAR MATRIX. HYDROXYAPATITE crystals are then deposited into the matrix to form bone.
A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.
The continuous turnover of BONE MATRIX and mineral that involves first an increase in BONE RESORPTION (osteoclastic activity) and later, reactive BONE FORMATION (osteoblastic activity). The process of bone remodeling takes place in the adult skeleton at discrete foci. The process ensures the mechanical integrity of the skeleton throughout life and plays an important role in calcium HOMEOSTASIS. An imbalance in the regulation of bone remodeling's two contrasting events, bone resorption and bone formation, results in many of the metabolic bone diseases, such as OSTEOPOROSIS.
The process of bone formation. Histogenesis of bone including ossification.
The inner and longer bone of the FOREARM.
Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts.
A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.
A circular structural unit of bone tissue. It consists of a central hole, the Haversian canal through which blood vessels run, surrounded by concentric rings, called lamellae.
The process by which cells convert mechanical stimuli into a chemical response. It can occur in both cells specialized for sensing mechanical cues such as MECHANORECEPTORS, and in parenchymal cells whose primary function is not mechanosensory.
Bone loss due to osteoclastic activity.
A large multinuclear cell associated with the BONE RESORPTION. An odontoclast, also called cementoclast, is cytomorphologically the same as an osteoclast and is involved in CEMENTUM resorption.
A parathyroid hormone receptor subtype that recognizes both PARATHYROID HORMONE and PARATHYROID HORMONE-RELATED PROTEIN. It is a G-protein-coupled receptor that is expressed at high levels in BONE and in KIDNEY.
Extracellular substance of bone tissue consisting of COLLAGEN fibers, ground substance, and inorganic crystalline minerals and salts.
A membrane-bound metalloendopeptidase that may play a role in the degradation or activation of a variety of PEPTIDE HORMONES and INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS. Genetic mutations that result in loss of function of this protein are a cause of HYPOPHOSPHATEMIC RICKETS, X-LINKED DOMINANT.
The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.
An abnormal hardening or increased density of bone tissue.
The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.
Thin outer membrane that surrounds a bone. It contains CONNECTIVE TISSUE, CAPILLARIES, nerves, and a number of cell types.
The growth and development of bones from fetus to adult. It includes two principal mechanisms of bone growth: growth in length of long bones at the epiphyseal cartilages and growth in thickness by depositing new bone (OSTEOGENESIS) with the actions of OSTEOBLASTS and OSTEOCLASTS.
The physical state of supporting an applied load. This often refers to the weight-bearing bones or joints that support the body's weight, especially those in the spine, hip, knee, and foot.
X-RAY COMPUTERIZED TOMOGRAPHY with resolution in the micrometer range.
Macromolecular organic compounds that contain carbon, hydrogen, oxygen, nitrogen, and usually, sulfur. These macromolecules (proteins) form an intricate meshwork in which cells are embedded to construct tissues. Variations in the relative types of macromolecules and their organization determine the type of extracellular matrix, each adapted to the functional requirements of the tissue. The two main classes of macromolecules that form the extracellular matrix are: glycosaminoglycans, usually linked to proteins (proteoglycans), and fibrous proteins (e.g., COLLAGEN; ELASTIN; FIBRONECTINS; and LAMININ).
An alloy of 60% cobalt, 20% chromium, 5% molybdenum, and traces of other substances. It is used in dentures, certain surgical appliances, prostheses, implants, and instruments.
A transmembrane protein belonging to the tumor necrosis factor superfamily that specifically binds RECEPTOR ACTIVATOR OF NUCLEAR FACTOR-KAPPA B and OSTEOPROTEGERIN. It plays an important role in regulating OSTEOCLAST differentiation and activation.
A hereditary disorder characterized by HYPOPHOSPHATEMIA; RICKETS; OSTEOMALACIA; renal defects in phosphate reabsorption and vitamin D metabolism; and growth retardation. Autosomal and X-linked dominant and recessive variants have been reported.
A 43-kDa peptide which is a member of the connexin family of gap junction proteins. Connexin 43 is a product of a gene in the alpha class of connexin genes (the alpha-1 gene). It was first isolated from mammalian heart, but is widespread in the body including the brain.
A secreted member of the TNF receptor superfamily that negatively regulates osteoclastogenesis. It is a soluble decoy receptor of RANK LIGAND that inhibits both CELL DIFFERENTIATION and function of OSTEOCLASTS by inhibiting the interaction between RANK LIGAND and RECEPTOR ACTIVATOR OF NUCLEAR FACTOR-KAPPA B.
The thickest and spongiest part of the maxilla and mandible hollowed out into deep cavities for the teeth.
Messages between computer users via COMPUTER COMMUNICATION NETWORKS. This feature duplicates most of the features of paper mail, such as forwarding, multiple copies, and attachments of images and other file types, but with a speed advantage. The term also refers to an individual message sent in this way.
The study of natural phenomena by observation, measurement, and experimentation.
Force exerted when gripping or grasping.
Disciplines concerned with the interrelationships of individuals in a social environment including social organizations and institutions. Includes Sociology and Anthropology.
All of the divisions of the natural sciences dealing with the various aspects of the phenomena of life and vital processes. The concept includes anatomy and physiology, biochemistry and biophysics, and the biology of animals, plants, and microorganisms. It should be differentiated from BIOLOGY, one of its subdivisions, concerned specifically with the origin and life processes of living organisms.
Mechanical food dispensing machines.
Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.
A microtubule subunit protein found in large quantities in mammalian brain. It has also been isolated from SPERM FLAGELLUM; CILIA; and other sources. Structurally, the protein is a dimer with a molecular weight of approximately 120,000 and a sedimentation coefficient of 5.8S. It binds to COLCHICINE; VINCRISTINE; and VINBLASTINE.
A multifunctional calcium-calmodulin-dependent protein kinase subtype that occurs as an oligomeric protein comprised of twelve subunits. It differs from other enzyme subtypes in that it lacks a phosphorylatable activation domain that can respond to CALCIUM-CALMODULIN-DEPENDENT PROTEIN KINASE KINASE.
A flavoprotein enzyme that catalyzes the univalent reduction of OXYGEN using NADPH as an electron donor to create SUPEROXIDE ANION. The enzyme is dependent on a variety of CYTOCHROMES. Defects in the production of superoxide ions by enzymes such as NADPH oxidase result in GRANULOMATOUS DISEASE, CHRONIC.
Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
Bone diseases caused by pathogenic microorganisms.
Infections resulting from the implantation of prosthetic devices. The infections may be acquired from intraoperative contamination (early) or hematogenously acquired from other sites (late).
Infections with bacteria of the genus STAPHYLOCOCCUS.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
Serum glycoprotein produced by activated MACROPHAGES and other mammalian MONONUCLEAR LEUKOCYTES. It has necrotizing activity against tumor cell lines and increases ability to reject tumor transplants. Also known as TNF-alpha, it is only 30% homologous to TNF-beta (LYMPHOTOXIN), but they share TNF RECEPTORS.
Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.
A type of endoplasmic reticulum lacking associated ribosomes on the membrane surface. It exhibits a wide range of specialized metabolic functions including supplying enzymes for steroid synthesis, detoxification, and glycogen breakdown. In muscle cells, smooth endoplasmic reticulum is called SARCOPLASMIC RETICULUM.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Monomeric subunits of primarily globular ACTIN and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell.
The fluid secreted by the lacrimal glands. This fluid moistens the CONJUNCTIVA and CORNEA.
The amount of mineral per square centimeter of BONE. This is the definition used in clinical practice. Actual bone density would be expressed in grams per milliliter. It is most frequently measured by X-RAY ABSORPTIOMETRY or TOMOGRAPHY, X RAY COMPUTED. Bone density is an important predictor for OSTEOPOROSIS.
Process whereby a cell, bodily structure, or organism (animal or plant) receives or detects a gravity stimulus. Gravity sensing plays an important role in the directional growth and development of an organism (GRAVITROPISM).