Skeletal system and Joints (Types of bone cells and short description of…
Skeletal system and Joints
Structural components of a typical synovial joint and a short description of each component.
Synovial joints: "joint eggs" Are the most lovable joints of the body, and all are diarthroses(freely movable).
Bursae and tendon sheaths: contain synovial fluid and often are associated with synovial joints.
Tendon sheath: is essentially an elongated bursa that wraps around a tendon like a bun around a hot dog.
Bursa: “purse,” is a flattened fibrous sac lined by a synovial membrane.
Articular disc:occur in the temporomandibular (jaw) joint, sternoclavicular joint, knee joint, and a few others .
Nerves and Vessels:Synovial joints are richly supplied with sensory nerve fibers that innervate the articular capsule.
Reinforcing ligaments:Some synovial joints are reinforced and strengthened by bandlike ligaments.
Synovial fluid:The viscous liquid inside the joint cavity is called synovial fluid because it resembles raw egg white (ovum = egg).
Weeping lubrication:nourishes the cells in the articular cartilages (cartilage is avascular) and lubricates the free surfaces of these cartilages, allowing the adjoining bones to move across each other with a minimum of friction.
Articular capsule:The joint cavity is enclosed by a two-layered articular capsule, or joint capsule.
Joint cavity: A feature unique to synovial joints, the joint cavity is a potential space that holds a small amount of synovial fluid.
Synovial membrane:composed of loose connective tissue.
Fibrous layer:dense irregular connective tissue is continuous with the periosteum layer of the joining bones.
Articular cartilage:The ends of the opposing bones are covered by articular cartilages composed of hyaline cartilage.
Classification, structure and function of fibrous and cartilaginous joint
Cartilaginous joints: The articulating bones are united by cartilage.
Symphyses: A joint where fibrocartilage unites the bones.
Function: is a fibrocartilaginous fusion between two bones.
Synchondroses: A joint where hyaline cartilage unites the bone.
constitute important postnatal longitudinal growth centers of the cranial base.
Fibrous joint: the bones are connected by fibrous tissue, namely dense regular connective tissue.
Gomphoses: "bolt" Is a peg-in socket joint.
Function: Short connecting fibers period metal ligaments.
Syndesmoses: "ligament" The bones are connected exclusively by ligaments, bands of fibrous tissue longer than those that occur in sutures.
Function: short connecting fibers.
Sutures: "seams" the bones are tightly bound by minimal amount of fibrous tissue.
Function: very short interconnecting fibers.
Types of bone cells and short description of each
Oseoclasts: Are derived from a lineage of white blood cells.
Osteocytes: Function to keep the bone matrix healthy.
Osteoblasts: are cells that actively produce and secrete the organic components of the bone matrix.
Osteogenic: Are stem cells that differentiate into the bone-forming osteoblast.
Components of a typical long bone and short description of each component
Short bones: roughly cub-shaped
Long Bones: are considerably longer than they are wide.
Nutrient arteries-: accompanied by one or two veins, enters the bone through the nutrient foramen.
Perforating fibers-: thick bundles of collagen that run from the periosteum into the bone matrix.
Endosteum-: Internal bone surfaces are covered by a much thinner connective tissue membrane.
medullary cavity-:The very center of the diaphysis of long bones contains no bone tissue at all.
Compact bone: covers all bone surface.
Periosteum: "around the bone" covers the entire outer surface of each bone except on the ends of the epiphyses, where articular cartilage occurs.
Songy bone: formed inside all bones.
Articular cartilage: The joint surface of each epiphysis is covered with a thin layer of hyaline cartilage.
Epiphyses: are the bone ends.
Diaphysis: or shaft, forms the long axis of a long bone.