Anatomy Physiology Lecture 6 Chapter 6 Osseous Tissue

Learning Objectives • Describe the functions of the skeletal system. • Classify bones and

The skeletal system includes • Bones of the skeleton • Cartilages, ligaments and other

Functions of the skeletal system • Support • Storage of minerals and lipids •

A Classification of Bones Bone shapes • Long • Flat • Short • Irregular

Bone structure = two types of bone • Compact bone (dense) • Spongy bone

Bone Histology Osseous tissue • Supporting tissue with a solid matrix • Crystals of

Cells in bone: • Osteocytes = mature bone cells • In lacunae • Connected

Compact bone and spongy bone • Basic unit of compact bone is an osteon

Bones and stress • Compact bone located where stresses are limited in direction •

The Distribution of Forces on a Long Bone

Bones are: • Covered by periosteum • Lined by endosteum Animation: Axial Dissections (check

Bone development and growth • Ossification = converting other tissue to bone • Calcification

Intramembranous ossification • Begins with osteoblast differentiation • Dermal bones produced • Begins at

Endochondral ossification • Cartilage model gradually replaced by bone at metaphysis • Increasing bone

Endochondral Ossification Animation: Endochondral Ossification (Check animations)

The Dynamic Nature of Bone continually changing • Remodeling • Exercise • Hormone levels

The skeleton is a calcium reserve • 99% body’s calcium in the skeleton •

Factors that Alter the Concentration of Calcium Ions in Body Fluids

Fracture repair • Fracture hematoma • External callus • Internal callus

Bone Markings (Surface Features) Bone markings • Are characteristic for each bone and each

Aging and the Skeletal System Effects of aging include • Osteopenia • Osteoporosis

You should now be familiar with: • The functions of the skeletal system. •

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Anatomy & Physiology Lecture 6 : Chapter 6 Osseous Tissue and Skeletal Structure Pages: 179 - 204 Lecturer: Dr. Barjis Room P 313 / P 307 Phone: (718) 260 -5285 E-Mail: ibarjis@citytech. cuny. edu Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Frederic H. Martini Fundamentals of

Learning Objectives • Describe the functions of the skeletal system. • Classify bones and identify the major markings. • Identify cell types in bone and list their functions. • Compare spongy and compact bone. • Compare intramembranous and endochondral ossification. • Discuss the effects of nutrition, hormones, exercise and aging on the bones. • Describe the types of fractures.

The skeletal system includes • Bones of the skeleton • Cartilages, ligaments and other connective tissues that stabilize and connect

Functions of the skeletal system • Support • Storage of minerals and lipids • Blood cell production • Protection • Leverage

A Classification of Bones Bone shapes • Long • Flat • Short • Irregular • Sesamoid • Sutural

Classification of Bones by Shape

Bone structure = two types of bone • Compact bone (dense) • Spongy bone (cancellous)

Bone Histology Osseous tissue • Supporting tissue with a solid matrix • Crystals of hydroxyapatite • Minerals deposited in lamellae • Covered by periosteum

Cells in bone: • Osteocytes = mature bone cells • In lacunae • Connected by canaliculi • Osteoblasts synthesize new matrix • Osteogenesis • Osteoclasts dissolve bone matrix • Osteolysis • Osteoprogenitor cells differentiate into osteoblasts

The Histology of Compact Bone

Compact bone and spongy bone • Basic unit of compact bone is an osteon • Osteocytes arranged around a central canal • Perforating canals extend between adjacent osteons • Spongy bone contains trabeculae

The Structure of Osseus Tissue

Bones and stress • Compact bone located where stresses are limited in direction • Spongy bone located where stresses are weaker or multi-directional

The Distribution of Forces on a Long Bone

Bones are: • Covered by periosteum • Lined by endosteum Animation: Axial Dissections (check the animations)

Bone development and growth • Ossification = converting other tissue to bone • Calcification = depositing calcium salts within tissues

Intramembranous ossification • Begins with osteoblast differentiation • Dermal bones produced • Begins at ossification center

Intramembranous Ossification

Endochondral ossification • Cartilage model gradually replaced by bone at metaphysis • Increasing bone length • Timing of epiphyseal closure differs • Appositional growth increases bone diameter

Endochondral Ossification

Endochondral Ossification Animation: Endochondral Ossification (Check animations)

Bone Growth at an Epiphyseal Cartilage

Appositional Bone Growth

The Circulatory Supply to a Mature Bone

The Dynamic Nature of Bone continually changing • Remodeling • Exercise • Hormone levels • Growth hormone and thyroxine increase bone mass • Calcitonin and PTH control blood calcium levels

A Chemical Analysis of Bone

The skeleton is a calcium reserve • 99% body’s calcium in the skeleton • Calcium ion concentration maintained by bones GI tract and kidneys • Calcitonin and PTH regulate blood calcium levels • Calcitonin decreases blood calcium levels • PTH increases blood calcium levels

Factors that Alter the Concentration of Calcium Ions in Body Fluids

Fracture repair • Fracture hematoma • External callus • Internal callus

Steps in the Repair of a Fracture

Bone Markings (Surface Features) Bone markings • Are characteristic for each bone and each individual • Markings include • Elevations • Projections • Depressions • Grooves and tunnels

Aging and the Skeletal System Effects of aging include • Osteopenia • Osteoporosis

The Effects of Osteoporosis

You should now be familiar with: • The functions of the skeletal system. • Bones and their major markings. • Cell types in bone and their functions. • Spongy and compact bone. • Intramembranous and endochondral ossification. • The effects of nutrition, hormones, exercise and aging on the bones. • The types of fractures.