Skeletal System
system comprised of all the bones, their cartilage, ligaments, and tendons.
Red bone marrow
one marrow located that produces red and white blood cells and platelets.
Yellow bone marrow
bone marrow that stores triglycerides.
Hemopoiesis
the process in which red bone marrow produces red blood cells, white blood cells, and platelets.
Diaphysis
the shaft or body section of the bone.
Epiphyses
the proximal and distal ends of the bone.
Metaphyses
the section of bone between the diaphysis and epiphyses.
Epiphyseal plate
Growth plate, made of cartilage, gradually ossifies into the epiphyseal line.
Epiphyseal line
a line of cartilage present at the junction of the diaphysis and epiphyses; a remnant of the epiphyseal plate.
Articular cartilage
Hyaline cartilage attached to bones at articulating joints.
Periosteum
a tough connective tissue surrounding the bone surface where it is not covered by articular cartilage
Medullary cavity
this cavity is the hollow, cylindrical space within the diaphysis that contains yellow bone marrow in adults.
Endosteum
membranous lining of the hollow cavity of the bone; contains bone-forming cells.
Osseus Tissue
also called bone tissue.
Hydroxyapatite
Hardy crystals consisting of calcium and phosphate that form the bone matrix.
Calcification
process that hardens bones by adding calcium phosphate and collagen.
Osteogenic cells
are the unspecialized stem cells that develop into osteoblasts.
Osteoblasts
bone building cells
Osteocytes
mature bone cells
Osteoclasts
bone-destroying cells
Compact bone tissue
type of bone tissue with few spaces and is the strongest form of osseous tissue.
Osteons
structural units of mature compact bone
Central canal
longitudinal channel in the center of each osteon; contains blood vessels, nerves, and lymphatic vessels; also known as the Haversian canal
Concentric lamellae
Calcified extracellular matrix arranged in multiple layers or rings; makes up the osteons
Lacune
spaces in bone matrix that house mature osteocytes
Canaliculi
extensions of the lacunae and are filled with extracellular fluid.
Spongy bone tissue
type of bone tissue that does not contain osteons; always located in the interior of bones; consists of trabeculae.
Trabeculae
lamellae arranged in irregular lattice in thin columns in spongy bone tissue.
Periosteal arteries
These arteries enter at numerous points to supply the compact bone.
Perforating canals
structures through which blood vessels enter and exit the bone shaft.
Interstitial lamellae
remains of old osteons that have been partially destroyed.
Circumferential lamellae
outer surface of compact bone; thin plates that extend around the bone.
Nutrient artery
large artery that enters compact bone near the middle of the diaphysis to deliver blood.
Nutrient foramen
a hole near the center of the diaphysis in which the nutrient artery and vein passes through.
Metaphyseal arteries
enter the metaphyses of a long bone and, together with the nutrient artery, supply the red bone marrow and bone tissue of the metaphyses.
Epiphyseal arteries
enters the epiphyses of a long bone and supplies red marrow and bone tissue of the epiphysis.
Nutrient veins
vein that enters the compact bone near the middele of the diaphysis to carry away blood.
Epiphyseal veins
veins that carry blood away from long bones
Metaphyseal veins
veins that exit through the metaphysis.
Periosteal veins
small veins that exit through the periosteum.
Ossification
the process of bone formation.
Mesenchyme
embryonic connective tissue from which all other connective tissues arise.
Intramembranous ossification
the process of bone formation directly within mesenchyme.
Endochondral ossification
the process of bone formation within hyaline cartilage that develops from mesenchyme.
Ossification centre
area in the cartilage model of a future bone where the cartilage cells hypertrophy, secrete enzymes that calcify their extracellular matrix, and die, and the area they occupied is invaded by osteoblasts that then lay down bone.
Chondroblast
immature cells that secrete the extracellular matrix of cartilage.
Hyaline cartilage model
a model produced by chondroblasts secreting cartilage extracellular matrix.
Perichondrium
a covering that develops around the hyaline cartilage model.
Primary ossification centre
the region that develops in the mid-region of the cartilage model where osseous tissue will replace cartilage.
Secondary ossification centre
the region that develops in the epiphyses, where bone replaces cartilage.
Bone remodelling
the ongoing replacement of old osseous tissue by new osseous tissue
Sex hormones
progestrone, estrogen, and testosterone
Parathyroid hormone
a hormone of the parathyroid gland that regulates the metabolism of calcium and phosphorus in the body.
Calcitonin
hormone from the thyroid gland that has the potential to decrease blood calcium level.
Long bone
bone of greater length than width and consists of a shaft and two extremities.
Short bone
cube shaped bone.
Flat bone
thin bone that can afford considerable protection.
Irregular bone
bone of complex shape and cannot be grouped into other categories.
Sesamoid bone
bone shaped like a sesame seed.