structure and function 6.1 Flashcards
cartilage
forerunner of most bones in embryonic development; forms a growth zone in bones of children. covers many joint surfaces in mature skeleton
skeletal system
composed of bones, cartilages and ligaments joined tightly to form a strong, flexible framework for body
ligaments
collagenous bands that hold bones together at joints
tendons
structurally similar to ligaments but attach muscle to bone
bone marrow
soft bloody or fatty material enclosed in bones
osseous tissue
hard, calcified tissue of bone
functions of skeletal system
support, protection, movement, blood formation, storage
osteogenic cells
stem cells that occur on bone surface, beneath fibrous connective tissue membranes that cover bone. give rise to osteoblasts. only bone cells that can divide and make more
osteoblasts
develop from osteogenic cells, lie in single layer to bone surface. synthesize organic matter of bone and deposit matrix
osteocytes
former osteoblasts that have become trapped in matrix they deposited. are in lacunae. pass nutrients, wastes, and chemical signals to each other through gap junctions
osteoclasts
large, multiple nuclei bone dissolving cells that develop from separate line of bone marrow stem cells. secrete hydrochloric acid and enzymes to dissolve osseous tissue
compact (dense) bone
forms outer shell that surrounds spongy bone. prevents bone marrow from seeping out, solid attachment surface for muscles, tendons, and ligaments. surface-parrallel layers. deeper-cylindrical units
diaphysis
shaft; elongated midsection of bone
epiphysis
expanded end of bone
periosteum
fibrous sheath that covers bone
