endochondral ossification Indirect Most bones from this way From hyaline

Step 4- bone remodels itself spongy bone sandwiches the compact bone. endochondral ossification- Indirect Most bones from this way From hyaline cartilage then grow into bones Step 1: Mesenchyme→Chondroblast→Hyaline Cartilage Step 2: Cartilage calcifies; perichondrium become osteoblasts Periosteal bone collar Forms (outer edges) Step 3: Primary Ossification Blood supply create cells to differentiate into Osteoblasts Step 4.Then osteoclasts digest the spongy bone creating the medullary cavity. Step 5. By birth the penetration of nutrient arteries into the epiphyseal areas results in secondary ossification centers with spongy bone Step 6- Remaining Hyaline cartilage becomes Growth plate = the epiphyseal plate Step 7-As humans approach the end of adolescence , an interaction of action of HGH, thyroid hormones and sex hormones trigger the “closure” or calcification of epiphyseal plates into bony remnants- Epiphyseal line Step 8- Only remaining cartilage becomes the Articulated cartilage at the epiphysis What are the functions of the skeletal system? ● Support and Lever Action (for movement) ● Protect Organ Skull Ribs ● Blood cell production ◦ RBC’s & WBC’s ● Stores calcium Ca++ needed by all cells, especially muscle cells What are the indications that bone is alive? I norganic mineral Protein Mineral is Calcium Phosphate Protein is Collagen Bone is rigid but not brittle they heal/repair when broken grow produce RBC Be able to diagram and label a typical long bone.

Epiphyses Diaphases Medullary cavity Nutrient chord Spongy bone Compact bone Articulated cartilage Epiphyseal line Endosteum Periosteum Characteristics Cartilage Bone Mechanical Properties Rigid but Flexible Hard and strong Mature Cell Chondrocytes (from chondroblasts) Osteocytes Composition of Matrix Protein Protein + Ca3(PO4) Vascularization Avascular Vascular Growth/Repair slow fast Membrane Perichondrium pariosteum Nerve Innervation no yes What are the types of bone? ● Long bones ● Sesamoid Sesamoid bone– small round & flat from within tendons ● Flat bones (have two parallel plates of compact bone with a thin layer of spongy bone sandwiched in between them. (ex Skull) Types of fractures: simple (inside skin) compound (breaks through the skin) complete- 2 pieces incomplete- little cracks greenstick- bowes/bends comminuted shattared transverse spiral Process of healing a bone fractures.