Bone Biology
Human Skeleton 9/12 Notes
Bone Biology
Bone Biology * Bone is both a tissue and an organ. It is a specific type of biological tissue with its own unique chemical and molecular structure. Bone is a unique combination of organic and inorganic components. * Two levels of study * Macroscopic: gross morphological features * Microscopic: aka histology, study of tissues * Two levels of histology * Cellular * Molecular
Bone Biology – Macroscopic * All bone in adult skeleton is found in two basic configurations: * Compact (cortical) bone * Very dense * Seemingly solid bone * Found on outer surface of all bones * In tubular (long and short) bones it is concentrated on walls of shafts * Subchondral bone is a variant of compact bone found at joints and covered by cartilage during life, it is smoother and shinier and lacks osteons and haversian systems * Cancellous (spongy, trabecular) bone * More porous * Honeycomb structure * Formed by bony columns (trabeculae) separated by large spaces * Found: under joint surface, at ends of tubular bones, inside flat bones (skull), inside vertebral bodies, at insertion sites for large tendons * Molecular and cellular structure identical in cancellous and compact bone * Only difference is porosity and distribution * Components of tubular bones, described according to centers of ossification * Diaphysis (shaft): main portion of tubular bone, primary ossification center of the bone * Epiphysis (ends): form joint surfaces, secondary ossification center of the bone * Metaphysis: expanded, flared ends of shafts, site of growth plates and fusion of diaphysis and epiphysis * Forces acting on surface of tubular bone * Diaphysis (hollow tube with thick walls): good as a solid cylinder for resistance and weight bearing, the thicker the cortical walls the stronger the cylinder * Epiphysis (joint surfaces): forces applied over a broad
Bone Biology
Bone Biology * Bone is both a tissue and an organ. It is a specific type of biological tissue with its own unique chemical and molecular structure. Bone is a unique combination of organic and inorganic components. * Two levels of study * Macroscopic: gross morphological features * Microscopic: aka histology, study of tissues * Two levels of histology * Cellular * Molecular
Bone Biology – Macroscopic * All bone in adult skeleton is found in two basic configurations: * Compact (cortical) bone * Very dense * Seemingly solid bone * Found on outer surface of all bones * In tubular (long and short) bones it is concentrated on walls of shafts * Subchondral bone is a variant of compact bone found at joints and covered by cartilage during life, it is smoother and shinier and lacks osteons and haversian systems * Cancellous (spongy, trabecular) bone * More porous * Honeycomb structure * Formed by bony columns (trabeculae) separated by large spaces * Found: under joint surface, at ends of tubular bones, inside flat bones (skull), inside vertebral bodies, at insertion sites for large tendons * Molecular and cellular structure identical in cancellous and compact bone * Only difference is porosity and distribution * Components of tubular bones, described according to centers of ossification * Diaphysis (shaft): main portion of tubular bone, primary ossification center of the bone * Epiphysis (ends): form joint surfaces, secondary ossification center of the bone * Metaphysis: expanded, flared ends of shafts, site of growth plates and fusion of diaphysis and epiphysis * Forces acting on surface of tubular bone * Diaphysis (hollow tube with thick walls): good as a solid cylinder for resistance and weight bearing, the thicker the cortical walls the stronger the cylinder * Epiphysis (joint surfaces): forces applied over a broad