6 HUMAN ANATOMY fifth edition MARIEB MALLATT WILHELM

6 HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM Power. Point® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham PART 1 Bones and Skeletal Tissues Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Cartilage § Location and basic structure § Found throughout adult body § Ear and epiglottis § Articular cartilages and costal cartilage § Larynx, trachea, and nose § Intervertebral discs and pubic symphysis § Where do you find each type of cartilage? Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Cartilage § § Is abundant in embryo Is surrounded by perichondrium Consists primarily of water Resilient tissue – springs back to original shape Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Types of Cartilage – Covered in CH 4 § Hyaline cartilage – (glassy) § Elastic cartilage – contains many elastic fibers § Fibrocartilage – resists strong compression and strong tension § Most abundant cartilage § Provides support through flexibility § Able to tolerate repeated bending § An intermediate between hyaline and elastic cartilage Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Cartilages in the Adult Body Copyright © 2008 Pearson Education, Inc. , publishing as

Growth of Cartilage § Appositional growth § Chondroblasts in surrounding perichondrium produce new cartilage § Interstitial growth § Chondrocytes within cartilage divide and secrete new matrix Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Tissues in Bone § Bones contain several types of tissues § Dominated by bone CT § Contain nervous tissue and Blood CT § Contain cartilage in articular cartilages § Contain ET lining blood vessels Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Function of Bones § § § Support – provides hard framework Movement – skeletal muscles use bones as levers Protection of underlying organs Mineral storage – reservoir for important minerals Blood-cell formation – bone contains red marrow Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Classification of Bones § § § Long bones – longer than wide – a shaft plus ends Short bones – roughly cube-shaped Flat bones – thin and flattened, usually curved Irregular bones – various shapes, do not fit into other categories Give an example of each type of bone Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Classification of Bones Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Gross Anatomy of Bones § § Compact bone – dense outer layer of bone

Structure of a Typical Long Bone § § § Diaphysis – “shaft” of a bone Epiphysis – ends of a bone Blood vessels – well vascularized Medullary cavity – hollow cavity filled with yellow marrow Membranes § Periosteum, perforating fibers (Sharpey’s fibers), and endosteum Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Structure of a Long Bone Copyright © 2008 Pearson Education, Inc. , publishing as

Structure of Short, Irregular, and Flat Bones § Flat bones, short bones, and irregular bones § Contain bone marrow but no marrow cavity § Diploë § Internal spongy bone of flat bones Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6. 4

Gross Anatomy of Bones § Bone design and stress § Anatomy of a bone reflects stresses § Compression and tension greatest at external surfaces Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6. 5 a

Bone Markings § § Superficial surfaces of bones reflect stresses on them There are three broad categories of bone markings § Projections for muscle attachment § Surfaces that form joints § Depressions and openings Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Markings Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Table

Microscopic Structure of Compact Bones Copyright © 2008 Pearson Education, Inc. , publishing as

6 HUMAN ANATOMY fifth edition MARIEB | MALLATT | WILHELM Power. Point® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham PART 2 Bones and Skeletal Tissues Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Chemical Composition of Bone § 35% organic components § Composed of cells, fibers, and organic substances § Collagen – abundant § 65% inorganic mineral salts § Primarily calcium phosphate § Resists compression Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Development § Ossification (osteogenesis) – bone-tissue formation § Membrane bones – formed directly from mesenchyme § Intramembranous ossification § Other bones – develop initially from hyaline cartilage § Endochondral ossification Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Intramembranous Ossification Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure

Endochondral Ossification § § All bones except some bones of the skull and clavicles Bones are modeled in hyaline cartilage Begins forming late in the second month of embryonic development Continues forming until early adulthood Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Stages in Endochondral Ossification Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin

Anatomy of Epiphyseal Growth Areas § In epiphyseal plates of growing bones § Cartilage is organized for quick, efficient growth § Cartilage cells form tall stacks § Chondroblasts at the top of stacks divide quickly § Pushes the epiphysis away from the diaphysis § Lengthens entire long bone Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Anatomy of Epiphyseal Growth Areas § § Older chondrocytes signal surrounding matrix to calcify Older chondrocytes then die and disintegrate § Leaves long trabeculae (spicules) of calcified cartilage on diaphysis side § Trabeculae are partly eroded by osteoclasts § Osteoblasts then cover trabeculae with bone tissue § Trabeculae finally eaten away from their tips by osteoclasts Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Organization of Cartilage within Epiphyseal Plate of Growing Long Bone Copyright © 2008 Pearson

Postnatal Growth of Endochondral Bones § During childhood and adolescence § Bones lengthen entirely by growth of the epiphyseal plates § Cartilage is replaced with bone CT as quickly as it grows § Epiphyseal plate maintains constant thickness § Whole bone lengthens Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Hormonal Regulation of Bone Growth § Growth hormone – produced by the pituitary gland § Stimulates epiphyseal plates § § Thyroid hormone – ensures that the skeleton retains proper proportions Sex hormones (estrogen and testosterone) § Promote bone growth § Later induces closure of epiphyseal plates Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Postnatal Growth of Endochondral Bones § As adolescence draws to an end § Chondroblasts divide less often § Epiphyseal plates become thinner § Cartilage stops growing § Replaced by bone tissue § Long bones stop lengthening when diaphysis and epiphysis fuse Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Remodeling § Bone is dynamic living tissue § 500 mg of calcium may enter or leave the adult skeleton each day § Cancellous bone of the skeleton is replaced every 3 – 4 years § Compact bone is replaced every 10 years Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Postnatal Growth of Endochondral Bones § Growing bones widen as they lengthen § Osteoblasts – add bone tissue to the external surface of the diaphysis § Osteoclasts – remove bone from the internal surface of the diaphysis § Appositional growth – growth of a bone by addition of bone tissue to its surface Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Remodeling § Bone deposit and removal § Occurs at periosteal and endosteal surfaces § Bone remodeling § Bone deposition – accomplished by osteoblasts § Bone reabsorption – accomplished by osteoclasts Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Remodeling, Spongy Bone Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Osteoclast – A Bone-Degrading Cell § § § A giant cell with many nuclei Crawls along bone surfaces Breaks down bone tissue § Secretes concentrated HCl § Lysosomal enzymes are released Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6. 13 a

$Repair of Bone Fractures § § Simple and compound fractures Treatment by reduction §$

Stages of Healing a Fracture Copyright © 2008 Pearson Education, Inc. , publishing as

Common Types of Fractures Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin

Disorders of Bones § Osteoporosis § Characterized by low bone mass § Bone reabsorption outpaces bone deposition § Occurs most often in women after menopause Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Osteoporosis Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6.

Disorders of Bones § Osteomalacia § Occurs in adults – bones are inadequately mineralized § Rickets § Occurs in children – analogous to osteomalacia Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

Disorders of Bones § Paget’s disease § Characterized by excessive rate of bone deposition § Osteosarcoma § A form of bone cancer Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

The Skeleton Throughout Life § § § Cartilage grows quickly in youth Skeleton shows fewer chondrocytes in the elderly Bones are a timetable § Mesoderm § Gives rise to embryonic mesenchyme cells § Mesenchyme § Produces membranes and cartilage § Membranes and cartilage ossify Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings

The Skeleton Throughout Life § § Skeleton grows until the age of 18– 21 years In children and adolescents § Bone formation exceeds rate of bone reabsorption § In young adults § Bone formation and bone reabsorption are in balance § § In old age reabsorption predominates Bone mass declines with age Copyright © 2008 Pearson Education, Inc. , publishing as Benjamin Cummings