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bones and skeletal
bones and skeletal tissues
Question | Answer |
---|---|
________ occucrs within the marrow caviites of the bones | hematopoiesis (blood cell formation) |
compact bone also called lamellar bone | dense outer layer that is smooth to the naked eye |
spongy bone | internal honeycomb of trabeculae filled with red or yellow marrow |
long bones consist of _______ and ______ | diaphysis and epiphysis |
diaphysis | tubular shaft that forms the axis of long bones; composed of compact bone that surrounds the medullary cavity |
yellow bone marrow | (fat) contained in the medullary cavity |
epiphysis | expanded ends of the long bones; exterior is compact bone and interior is spongy bone |
joint surface | covered with articular (hyaline) cartilage |
epiphyseal line | separates the diaphysis from the epiphysis |
osteoblasts | bone forming cells |
osteocytes | mature bone cells |
osteoclasts | large cells that resorb or break down bone matrix |
mesenchyme --> osteoblast --> osteocyte --> osseous (bone) --> compact and spongy bone | osteogenic cells - develops into an osteoblast; osteoblast - forms bone matrix; osteocyte - maintains bone tissue; osteoclast- functions in resorption, teh breakdown of bone matrix. |
periosteum | part of bone memebrane that is double layered protective membrane covers all but joint surfaces in long bones; |
inner osteogenic layer | located on periosteum. composed of osteoblasts and osteoclasts |
sharpey's fibers (collagen) | secures the periosteum to the underlying bone |
endosteum | delicate membrane covering internal surfaces of bone |
short, irregular and flat bones | no diaphysis or epiphysis. contain bone marrow b/w the trabeculae, but no marrow cavity like long bone. |
osteon or haversian system | structural unit of compact bone |
osteon | little hollow weight-bearing pillars placed next to each other in compact bone |
lamella | osteons contain lamella that contain collagen fibers giving compact bone its tensile strength. |
collagen fibers | solubal gelatin white fibers of cross linked connective tissue; collagen fibers in adjacent lamella run in opposite direction to allow bone to withstand torsion. it gives the bones its tensile strength and allow bone to resist stretch and twisting |
haversian canal | central canal containing blood vessels |
volkmann's canals | channels lying at the right angles to the central canal, connecting blood supply of the periosteum to that of teh haversian canal. direct communication with medulla provided by blood vessels in volkmann's canal |
chemical composition of bone | organic 35% (osteoblasts, osteoclasts, osteocytes, osteoid). inorganic 65% (calcium phosphate crystals and other mineral salts) |
osteiod | consists of ground substance and collagen fibers made by osteoblasts. |
calcium phosphate crystals | responsible for bone hardness and its resistance to compression |
skeletal cartilages | contain no blood vessels or nerves |
3 types of skeltal cartilages | hyaline, fibrocartilage, and elastic. all 3 types contain cells called chondrocytes encased in lacunae containing ground substances |
hyaline cartilage | most abundant skeletal cartilage. present in articular, costal, respiratory, and nasal cartilages |
elastic cartilage | similar to hyaline but contains elastic fibers. found in external ear and epiglottis |
fibrocartilage | highly compressed with great tensile strength. contains collagen fibers. found in menisci of the knee and in intervertebral discs |
remodeling units | osteoblasts and osteoclasts. involves bone deposition and bone resorption. occurs at the surface of periosteum and endosteum |