ELAINE N. MARIEB EIGHTH EDITION 5 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation by Jerry L. Cook, Sam Houston University ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY The Skeletal System

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Skeletal System  Parts of the skeletal system 1. Bones (skeleton)3. Ligaments 2. Joints 4. Cartilages  Divided into two divisions 1. Axial skeleton head, neck, & trunk 2. Appendicular skeleton limbs, pectoral girdle, pelvic girdle.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Functions of Bones  Support framework for body  Protection of soft organs by skull, rib cage, vertebrae  Movement by attached muscles  Storage of minerals & fats; most important minerals are Ca + & Phosphorus  Blood cell formation – hematopoiesis, in marrow

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bones of the Human Body  The adult skeleton has 206 bones  Two basic types of bone tissue 1. Compact bone  Homogeneous - dense 2. Spongy bone  Small needle-like pieces of bone  Many open spaces Figure 5.2b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Bones on the Basis of Shape Figure 5.1

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Bones  Long bones a. Typically longer than wide b. Have a shaft with heads at both ends and a medullary cavity c. Contain mostly compact bone  Examples: femur, ulna, tibia, fibula, phalanges (fingers & toes), metacarpals (palm)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Bones  Short bones a. Generally cube-shape b. Contain mostly spongy bone, no cavity  Examples: carpals (wrist), tarsals (ankle)  Sesamoid – special type of short bone  a. Develop within tendons  Example: patella (kneecap)

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Bones  Flat bones a. Thin and flattened b. Usually curved c. Thin layers of compact bone around a layer of spongy bone  Examples: skull, ribs, sternum

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Classification of Bones  Irregular bones a. Irregular shape b. Do not fit into other bone classification categories  Example: vertebrae, coxal (hip), scapula c. Two or more different shapes; not specifically long or short.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Gross Anatomy of a Long Bone  Diaphysis a. shaft b. Composed of compact bone  Epiphysis a. Ends of the bone b. Composed mostly of spongy bone Figure 5.2a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structures of a Long Bone  Periosteum a. Outside covering of diaphysis b. Fibrous connective tissue membrane  Sharpey’s fibers a. Secure periosteum to underlying bone  Arteries a. Supply bone cells with nutrients Figure 5.2c

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structures of a Long Bone  Articular cartilage a. Covers the external surface of the epiphyses b. Made of hyaline cartilage (slippery surface) c. Decreases friction at joint surfaces Figure 5.2a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Structures of a Long Bone  Medullary cavity a. Cavity of the shaft b. Contains yellow marrow (stores fat) in adults c. Contains red marrow (for blood cell formation) in infants Figure 5.2a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Markings  Surface features of bones  Sites of attachments for muscles, tendons, & ligaments  Passages for nerves & blood vessels  Categories of bone markings  Projections and processes – grow out from the bone surface  Depressions or cavities – indentations

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Bone  Osteon (Haversian System) a. A unit of bone  Central (Haversian) canal a. Opening in the center of an osteon b. Carries blood vessels and nerves  Perforating (Volkman’s) canal a. Canal perpendicular to the central canal b. Carries blood vessels and nerves

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Bone Figure 5.3

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Bone  Lacunae  Cavities containing bone cells (osteocytes)  Arranged in concentric rings  Lamellae  Rings around the central canal  Sites of lacunae Detail of Figure 5.3

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of Bone  Canaliculi  Tiny canals through which bone cells indirectly receive nourishment  Radiate from the central canal to lacunae  Form a transport system Detail of Figure 5.3

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Changes in the Human Skeleton  In embryos, the skeleton is primarily hyaline cartilage  During development, much of this cartilage is replaced by bone  Cartilage remains in isolated areas a. Bridge of the nose b. Parts of ribs c. Joints

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Developmental Aspects of the Skeletal System  At birth, the skull bones are incomplete  Bones are joined by fibrous membranes called fontanelles (soft spots )  Fontanelles are completely replaced with bone within two years after birth.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Bone Growth  Epiphyseal plates allow for growth (in length) of long bone during childhood a. New cartilage is continuously formed b. Older cartilage becomes ossified  Cartilage is broken down  Bone replaces cartilage  Bones are remodeled and lengthened until growth stops a. Bones change shape somewhat b. Bones grow in width

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Long Bone Formation and Growth Figure 5.4a

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Long Bone Formation and Growth Figure 5.4b

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Types of Bone Cells  Osteocytes a. Mature bone cells  Osteoblasts a. Bone-forming cells  Osteoclasts a. Bone-destroying cells b. Break down bone matrix for remodeling and release of calcium (activity of osteoclasts increase when Ca + levels in blood drop.)  Bone remodeling is a process by both osteoblasts and osteoclasts.

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Repair of Bone Fractures 1. Hematoma (blood-filled swelling) is formed (Blood Clot) 2. Break is splinted by fibrocartilage to form a callus 3. Fibrocartilage callus is replaced by a bony callus 4. Bony callus is remodeled to form a permanent patch

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Stages in the Healing of a Bone Fracture Figure 5.5

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Axial and Appendicular Skeleton  Axial - Forms the longitudinal part of the body  Divided into three parts 1.Skull 2.Vertebral column 3.Bony thorax (ribs, sternum) (4).Hyoid  Appendicular 1. Limbs (appendages) 2. Pectoral Girdle a.clavicle b.scapula 3. Pelvic Girdle – (hips) a.ilium b.ischium c.pubic

Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Axial Skeleton Figure 5.6