Skeletal System, Osteon

Red bone marrow

A highly vascularized connective tissue located in microscopic spaces between trabeculae of spongy bone tissue.

Osteoclast

A large, mulinuclear cell that resorbs (destroys) bone matrix

Osteoblast

Cell formed from an osteogenic cell that participates in bone formation by secreting some organic components and inorganic salts

Epiphyseal Plate/Line

First - the hyaline cartilage plate in the metaphysis of a lone bone; site of lengthwise growth of bones. Second, The remnant of the first in the metaphysis of a long bone.

Structures of the osteon

Osteon, Lamellae, Central (Haversian) canal, Perforating (Volkmann's) canal, Lacunae, Osteocytes, Canaliculi, Periosteum, Endosteum

Canaliculi

Small channel or canal, as in bones, thwere they connect lacunae.

Endosteum

The membrane that lines the medullary (marrow) cavity of bones, consisting of osteogenic cells and scattered osteoclasts.

Irregular Bone

a bone that has a complex shape that doesn't fit into the other categories of bone (eg vertebrae and hips)

Bone Shapes

long, short, flat, irregular

Flat Bone

thin, usually curved bones located in skull, sternum, ribs, scapulae

Central Haversion Canal

A microscopic tube running the length of the spinal cord in the grey commissure. A circular channel running longitudinally in the center of an osteon (haversian system) of mature compact bone, containing blodd and lymphatic vessels and nerves.

Perforating (Volkmann's) Canal

A minute passageway by means of which blood vessels and nerves from the periosteum penetrate into compact bone.

Lacunae

A small, hollow spaces, such as those found in bones in which the osteocytes lie.

Short Bone

A type of bone that is roughly cube shaped. The carpals are short bones.

Compact (dense) bone tissue

Bone tissue that contains few spaces between osteons (haversian systems); forms the external portion of all bones and the bulk of the diaphysis (shaft) of long bones; is found immediately deep to the periosteum and external spongy bone.

Spongy (cancellous) Bone tissue

Bone tissue that that consists of an irregular latticework of thin plates of bone called trabeculae; spaces between trabeculae of some bones are filled with red bone marrow; found inside short, flat, and irregular bones and in the epiphses (ends) of long bones.

Lamellae

Concentric rings of hard, calcified extracellular matrix found in compact bone.

Structures of the long bone

Diaphysis, Epiphysis, Epiphyseal Plate/Line, Medullary Cavity, Bone Marrow

Osteocytes

Located in the lacunae, these are mature osteoblasts, which monitor and maintain the bone matrix.

Osteon

The basic unit of structure in adult compact bone, consisting of a central (haversian) canal with it's concertrically arranged lamellae, lacunae, osteocytes, and canaliculi. Also called haversian system.

Periosteum

The covering of a bone that consists of connective tissue, osteogenic cells, and osteoblasts; is essential for bone growth, repair and nutrition. Anchored to the bone by bundles of collagen called perforating or Sharpy's fibers.

Epiphysis

The end of the long bones, usually larger in diameter than the shaft (diaphysis)

Long Bone

The most common class of bone in the body, long bones have a well-defined shaft (the diaphysis) and two well-defined ends (the epiphyses). Fingers, Humerus, phallanges. Bones that are longer than are wide.

Diaphysis

The shaft of the long bone

Medullary Cavity

The space within the diaphysis of a bone that contains yellow bone marrow. Also called marrow cavity.

What types of tissues make up the skeletal system

osseous tissue, epithelial tissue, dense irregular collagenous tissue, and adipose tissue