SKELETAL SYSTEM Functions of the Skeletal System Bones

SKELETAL SYSTEM

Functions of the Skeletal System • • • Bones are made of OSSEOUS TISSUE Support Protection Movement Blood cell formation (bone marrow) - hematopoeisis Storage of organic and inorganic materials (salt, calcium, potassium, lipids…. )

ORGANIZATION • About 206 bones in the adult body • 2 Main Divisions – Axial & Appendicular

Axial Skeleton • • • Head, neck, trunk Skull Hyoid Bone Vertebral Column Thoracic Cage (ribs, 12 pairs) Sternum

Hyoid Bone The hyoid bone is unique because it is the only bone that is not attached to any other bones.

Appendicular Skeleton • Limbs & Bones that connect to the o Pectoral Girdle (shoulders) o Pelvic Girdle (hips)

BONE STRUCTURE - Long Bone 1. Epiphysis 2. Diaphysis 3. Articular Cartilage 4. Periosteum

Inside the Long Bone Medullary Cavity – hollow chamber filled with bone marrow Red Marrow (blood) Yellow Marrow (fat) Endosteum – lining of the medullary

Types of Bone Tissue Compact (wall of the diaphysis) Spongy (cancellous, epiphysis) - red marrow

Structure of a Long Bone Figure 6. 3 a-c

Review the Structure of a Long Bone Matching quiz at http: //www. mhhe. com/biosci/a p/holehaap/student/olc 2/chap 0 7 matching 01. html

Microscopic Structure MATRIX - where the bone cells live OSTEOCYTES - mature bone cells, enclosed in tiny chambers called LACUNAE OSTEOCYTES form rings (LAMELLAE) around a HAVERSIAN CANAL which houses blood vessels Osteocytes are linked by CANALICULI Haversian Canals are linked by VOLKMAN's CANALS

Compact Bone BONE COLORING!

Test Yourself Find the. . . Haversian Canal Volkman's Canal Lamellae Spongy Bone Compact Bone

BONE DEVELOPMENT & GROWTH 1. Intramembranous bones – flat, skull 2. Endochondral bones – all other ALL BONES START AS HYALINE CARTILAGE, areas graduallly turn to bone PRIMARY OSSIFICATION CENTER (shaft) SECONDARY OSSIFICATION CENTER (ends)

Bone Development & Growth EPIPHYSEAL DISK (growth plate) is a band of cartilage between the epiphysis and diaphysis These areas increase bone length as the cells ossify Cartilage becomes OSTEOBLASTS become OSTEOCYTES

RESORPTION OSTEOCLASTS - dissolve bone tissue to release minerals, process is called RESORPTION

Bone Growth

Bone Growth

Abnormal Bone Conditions • BONE SPURS: abnormal growth. Can occur on any bone (e. g. heel). • OSTEOPOROSIS: Increased activity of osteoclasts cause a break down bone, and the subsequent fewer minerals in the extracellular matrix make it fragile. The spongy bone especially becomes more porous. • Men get it as well as women. What’s the best way to prevent osteoporosis? Exercise! What does exercise do? Makes bones bigger. • The most common bone used for a bone graft is the iliac bone of the hip.

Rheumatoid arthritis is an autoimmune disease which causes joint stiffness and bone deformity Source: http: //www. thetimes. co. uk/tto/public/article 3233439. ece

SCOLIOSIS is a lateral curve in the spine

KYPHOSIS is a hunchback curve

LORDOSIS is a swayback in the lower region.

ANKYLOSIS is severe arthritis in the spine and the vertebrae fuse.