Classification of Bones: by Shape 12/14 Long bones – Longer than wide (i.e. humerus, femur) Short bones – Cube-shaped bones (i.e. wrist and ankle) – Bones that form within tendons e.g. patella BIOL 105 Lab 4B-bone1 Lab 4B-BIO 105

Classification of Bones by Shape Flat bones Thin, flat, slightly curved (i.e. skull, sternum) Irregular bones -almost impossible to describe the shape Complicated shapes (i.e. vertebrae, hip)

Functions of Bones 1.Support: For the body and soft organs 2.Protection: For brain, spinal cord, and vital organs 3.Movement: Muscles attached to bones act as levers 4.Storage: Minerals (calcium and phosphorus) and growth factors Triglycerides (fat) 5.Blood cell formation (hematopoiesis) in marrow cavities 6.Hormone production

Gross anatomy : Compact bone – Dense outer layer Spongy (cancellous) bone – Honeycomb of trabeculae filled with bone marrow BIOL 105 Lab 5B-bone4

Long Bone Structure Diaphysis (shaft)-tube-like center of bone – Compact bone surrounds medullary (marrow) cavity – Medullary cavity in children contains red bone marrow; in adults contains yellow marrow (fat) Epiphyses-ends of long bones – Spongy bone interior – Epiphyseal line (remnant of growth plate)- separates diaphysis and epiphysis – Joint surfaces covered with articular (hyaline) cartilage BIOL 105 Lab 5B-bone5

Spongy Bone Trabeculae – No osteons – Contain irregularly arranged lamellae, osteocytes, and canaliculi – Capillaries in endosteum (innermost lining membrane) supply nutrients BIOL 105 Lab 5B-bone6

Membranes of Bone Periosteum—double layered; very strong, leathery, – Outer layer: dense regular connective tissue – Inner osteogenic layer Osteoblasts (bone-forming cells) Osteoclasts (bone-destroying cells) Osteogenic cells (stem cells) – Has nerve fibers, blood vessels, and lymphatic vessels which enter bone via nutrient foramina Endosteum – Delicate membrane on internal surfaces of bone; primarily areolar tissue – Also contains osteoblasts and osteoclasts BIOL 105 Lab 5B-bone7

Microscopic Anatomy of Bone: Compact Bone Haversian system, or osteon—structural unit – Lamellae Weight-bearing Column-like matrix tubes – Central (Haversian) canal Contains blood vessels and nerves BIOL 105 Lab 5B-bone8

Volkmann’s (Perforating) canals – At right angles to central canal – Connects blood vessels and nerves of periosteum with central canal Lacunae—small cavities that contain osteocytes Canaliculi— hair like canals that connect lacunae to each other and central canal BIOL 105 Lab 5B-bone9

10

Bone Markings: Depressions and Openings Meatus- canal-like passageway Fossa-shallow depression Sinus-cavity within a bone Groove-shallow depression Fissure-narrow, slit-like opening Foramen-opening through a bone BIOL 105 Lab 5B-bone11

Bone Markings: Projections Sites of muscle and ligament attachment 1.Tuberosity—rounded projection 2.Crest—narrow, prominent ridge 3.Trochanter—large, blunt, irregular surface 4.Line—narrow ridge of bone 5.Tubercle—small rounded projection 6.Epicondyle—raised area above a condyle 7.Spine—sharp, slender projection 8.Process—any bony prominence 9. Condyle -- Rounded articular projection BIOL 105 Lab 5B-bone12

Projections: help to form joints –Head---Bony expansion on a narrow neck –Facet--Smooth, nearly flat articular surface –Condyle--Rounded articular projection –Ramus--Armlike bar LABWORK 1. List, identify, and describe the different types of bones and long bone structure specifically. 2. List, identify, and describe items associated with the microscopic structure of bone tissue. BIOL 105 Lab 5B-bone13