Bone Tissue Flashcards
6 Functions of the skeletal system
support, protect, movement, mineral homeostasis, blood cell production, triglyceride storage
7 Parts of a long bone
diaphysis, epiphyses, metaphyses, articular cartilage, periosteum, medullary cavity, endosteum
Diaphysis
long bone shaft
Epiphyses
proximal and distal ends of the long bone
Metaphyses
region between the diaphysis and epiphysis; contains an epiphyseal (growth) plate
Epiphyseal plate
layer of hayline cartilage that allows the diaphysis of the bone to grow in length; becomes epiphyseal line when growth stops
Articular cartilage
thin layer of hyaline cartilage covering the part of the epiphysis where the bone forms a joint; reduces friction and absorbs shock
Periosteum
tough connective tissue sheath with blood supply that surrounds bone surface wherever it is not covered by articular cartilage; protects bone, assists in fracture repair, nourishes, attachment point for ligaments and tendons
What attaches periosteum to underlying bone?
perforating fibers (Sharpey’s fibers)
Medullary (marrow) cavity
hollow cavity with diaphysis that contains fatty yellow bone marrow and blood vessels in adults
Endosteum
thin membrane that lines medullary cavity
What is the most abundant mineral salt in osseous tissue?
calcium phosphate
4 Cells in bone tissue
osteoprogenitor, osteoblasts, osteocytes, osteoclasts
Osteoprogenitor
undergo cell division and develop into osteoblasts; found along the inner portion of the periosteum, in the endosteum, and in the canals within bone that contain blood vessels
Osteoblasts
synthesize and secrete collagen fibers and other compounds to form ECM, initiate calcification; mature into osteocytes
What is calcification?
as mineral salts are deposited in the framework formed by the collagen fibers of the ECM, they crystallize and the tissue hardens
Osteocytes
mature bone cells, maintain daily homeostasis (eg. exchange of nutrients and wastes with blood)
Osteoclasts
releases powerful lysosomal enzymes and acids on the side of the cell that faces the bone surface that digest the protein and mineral components of underlying ECM (bone resorption); help regulate blood calcium levels
Compact bone
found beneath the periosteum of all bones and makes up the bulk of the diaphysis of long bones, provides protection and support
How are osteons arranged in compact bone?
aligned in the same direction and are parallel to the length of the diaphysis
Concentric lamallae
circular plates of mineralized ECM of increasing diameter, surrounding a small network of blood vessels and nerves located in the central canal
Lacunae
spaces between lamallae that contain osteocytes