Bone structure, classification and remodeling

primary functions of skeletal system

Support

Storage of Minerals (calcium), growth factors, and Fat/Lipids (in yellow marrow)

Blood Cell Formation in red marrow (Hematopoiesis)

Protection

Movement (force of motion)

Inorganic salt storage (Calcium & Phosphorus)

sesamoid bones

small and flat; develop inside tendons near joints of knees, hands, and feet Ex. patella

compact bone

Hard and dense, but not solid, bone tissue that is beneath the outer membrane of a bone. made of osteons

spongy bone

Layer of bone tissue having many small spaces and found just inside the layer of compact bone. made of trabeculae filled with yellow bone marrow

diaphysis

shaft of a long bone; covered in compact bone

epiphysis

ends of the ling bone; contains spongy bone

medullary cavity

cavity within the shaft of the long bones filled with bone marrow

epiphyseal line

separates diaphysis and epiphysis

periosteum

membrane that covers outer surface of bone

components of bone matrix

calcium phosphate (inorganic) and collagen fibers (organic)

calcium phosphate

makes bone hard and able to withstand compression; inorganic

collagen fibers

makes bone flexible, tough and able to twist and bend; organic

canaliculi

Small pathways "canals" for blood vessels; exchange nutrients and waste

osteocytes

Mature bone cells; in lacunae which is in layers of the lamellae and connected by canaliculi; maintain bone matrix

osteoblasts

bone makers; "build"; secrete osteoid to turn into osteocytes

osteoclasts

bone dissolvers; "break"; located in lacunae

osteon (Haversian system)

basic unit of compact bone; arranged in concentric lamellae

Central Canal (Haversian canal)

one of a network of tubes running through compact bone that contains blood vessels and nerves; runs lengthwise in a long bone

perforating canals

run perpendicular to central canals, connect osteons to each other to share nutrients; run widthwise in a long bone

lamellae

Concentric rings made up of groups of hollow tubes of bone matrix

Sharpey's fibers

connects periosteum to the rest of the bone at circumferential lamellae

endosteum

inner membrane that lines the medullary cavity of long bones

trabeculae

spiky, irregular latticework of thin bony plates in spongy bone tissue (letter C in the picture)

2 parts of the skeleton

axial skeleton and appendicular skeleton

Type of cartilage found at the joints

hyaline cartilage

osteogenic cells

bone stem cells

purpose of epiphyseal plate in long bone

"growth plate:; where bone growth occurs; becomes epiphyseal line when ossification is complete

Basic types of bone in the skeletal system

long bones, short bones, flat bones, irregular bones, sesamoid bones

long bones

longer than they are wide (ex: femur, humerus)

short bones

cube shaped bones of the wrist and ankle

flat bones

thin, flat, and curved; ex. the ribs, breastbone, and skull.

irregular bones

complicated shapes; ex. bones of the vertebrae and face

long bone labeled

Make sure you know the basic parts of the long bone.

osteon labeled

Make sure you know the basic parts of the osteon.

Osteon

structural unit of compact bone

Red bone marrow

active site of hematopoiesis, where new blood cells are produced, including red blood cells, white blood cells, and platelets. Found in flat bones

Yellow bone marrow

serves as a fat storage area, It contains adipocytes (fat cells). Found in long bones