Bones and Skeletal Tissues Exercise 9

Contains no blood vessels or nerves Skeletal Cartilage Contains no blood vessels or nerves Surrounded by the perichondrium (dense irregular connective tissue) that resists outward expansion Three types – hyaline, elastic, and fibrocartilage

Bones and Cartilages of the Human Body Figure 6.1

Classification of Bones Axial skeleton – bones of the skull, vertebral column, and rib cage Appendicular skeleton – bones of the upper and lower limbs, shoulder, and hip

Bulges, depressions, and holes that serve as: Bone Markings Bulges, depressions, and holes that serve as: Sites of attachment for muscles, ligaments, and tendons Joint surfaces Conduits for blood vessels and nerves

Bone Markings: Projections – Sites of Muscle and Ligament Attachment Tuberosity – rounded projection Crest – narrow, prominent ridge of bone Trochanter – large, blunt, irregular surface Line – narrow ridge of bone

Bone Markings: Projections – Sites of Muscle and Ligament Attachment Tubercle – small rounded projection Epicondyle – raised area above a condyle Spine – sharp, slender projection Process – any bony prominence

Bone Markings: Projections – Projections That Help to Form Joints Head – bony expansion carried on a narrow neck Facet – smooth, nearly flat articular surface Condyle – rounded articular projection Ramus – armlike bar of bone

Bone Markings: Depressions and Openings Meatus – canal-like passageway Sinus – cavity within a bone Fossa – shallow, basinlike depression Groove – furrow Fissure – narrow, slitlike opening Foramen – round or oval opening through a bone

Gross Anatomy of Bones: Bone Textures Compact bone – dense outer layer Spongy bone – honeycomb of trabeculae filled with yellow bone marrow

Long bones consist of a diaphysis and an epiphysis Diaphysis Structure of Long Bone Long bones consist of a diaphysis and an epiphysis Diaphysis Tubular shaft that forms the axis of long bones Composed of compact bone that surrounds the medullary cavity Yellow bone marrow (fat) is contained in the medullary cavity

Structure of Long Bone Figure 6.3

Periosteum – double-layered protective membrane Bone Membranes Periosteum – double-layered protective membrane Outer fibrous layer is dense regular connective tissue Inner osteogenic layer is composed of osteoblasts and osteoclasts Richly supplied with nerve fibers, blood, and lymphatic vessels, which enter the bone via nutrient foramina Secured to underlying bone by Sharpey’s fibers Endosteum – delicate membrane covering internal surfaces of bone

Structure of Short, Irregular, and Flat Bones Thin plates of periosteum-covered compact bone on the outside with endosteum-covered spongy bone (diploë) on the inside Have no diaphysis or epiphyses Contain bone marrow between the trabeculae

Structure of a Flat Bone Figure 6.4

Location of Hematopoietic Tissue (Red Marrow) In infants Found in the medullary cavity and all areas of spongy bone In adults Found in the diploë of flat bones, and the head of the femur and humerus

Microscopic Structure of Bone: Compact Bone Osteocytes – mature bone cells Lacunae – small cavities in bone that contain osteocytes Canaliculi – hairlike canals that connect lacunae to each other and the central canal

Microscopic Structure of Bone: Compact Bone Figure 6.6a, b

Chemical Composition of Bone: Organic Osteoblasts – bone-forming cells Osteocytes – mature bone cells Osteoclasts – large cells that resorb or break down bone matrix Osteoid – unmineralized bone matrix composed of proteoglycans, glycoproteins, and collagen

Chemical Composition of Bone: Inorganic Hydroxyapatites, or mineral salts Sixty-five percent of bone by mass Mainly calcium phosphates Responsible for bone hardness and its resistance to compression

Common Types of Fractures Table 6.2.1

Common Types of Fractures Table 6.2.2

Common Types of Fractures Table 6.2.3