THE SKELETAL SYSTEM The Skeletal System The skeletal

THE SKELETAL SYSTEM

The Skeletal System The skeletal system includes: Bones Cartilages Joints Ligaments Other connective tissues Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Skeletal System Functions of the Skeletal System Support against gravity Storage Calcium, phosphorous Fat Blood cell production Protection of soft internal organs Leverage for muscle action Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Structure of Bone (Osseous Tissue) Specialized 2% of bone weight Strong flexible matrix Calcium cells phosphate crystals Two-thirds of bone weight Collagen fibers Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Structure of Bone Macroscopic Features of Bone General shapes of bones Long bones (e. g. , humerus) Short bones (e. g. , carpal bones) Flat bones (e. g. , parietal bone) Irregular bones (e. g. , vertebra) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Structure of Bone Shapes of Bones Figure 6 -1

The Structure of Bone Features in a Long Bone Diaphysis (shaft) Compact (dense) bone Marrow cavity Epiphyses Spongy (ends) (cancellous) bone Articular cartilage Periosteum (covering) Endosteum (lining) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Structure of Bone The Structure of a Long Bone Figure 6 -2

The Structure of Bone Microscopic Features of Bone Periosteum Outer fibrous layer Inner cellular layer Osteocytes Within lacunae (holes) in matrix Between lamellae of matrix Branches within canaliculi Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Structure of Bone Microscopic Features of Bone Osteon—Basic functional unit of compact bone; columnar in shape Strong in long axis of bone Concentric layers of osteocytes Concentric layers of matrix (lamellae) Central (Haversian) canal Axial tunnel for blood vessels Perforating canal Radial tunnel for blood vessels Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Structure of Bone Structure of a Typical Bone Figure 6 -3(a)

The Structure of Bone Structure of a Typical Bone Figure 6 -3(b)

The Structure of Bone Microscopic Features of Spongy Bone No osteons Lamellae as trabeculae Arches, rods, plates of bone Branching network of bony tissue Strong in many directions Red marrow (blood forming) spaces Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Structure of Bone Cells in Bone Osteocytes Mature bone cells between lamellae Osteoclasts Source of acid, enzymes for osteolysis Calcium homeostasis Osteoblasts Responsible for osteogenesis (new bone) Source of collagen, calcium salts Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Formation and Growth Intramembranous Ossification—Process of converting other tissues to bone Forms flat bones of skull, mandible, clavicle Stem cells differentiate to osteoblasts Produces spongy bone, then compact bone Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Formation and Growth Bone Formation in 16 -Week-Old Fetus Figure 6 -4

Bone Formation and Growth Endochondral Ossification Most bones formed this way Cartilage model replaced by bone Replacement begins in middle (diaphysis) Replacement follows in ends (epiphyses) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies. Enlarging chondrocytes within calcifying matrix Cartilage model Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -5 2 of 6

Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies. Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone. Enlarging chondrocytes within calcifying matrix Epiphysis Diaphysis Bone formation Cartilage model Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -5 3 of 6

Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies. Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone. Blood vessels penetrate the cartilage. New osteoblasts form a primary ossification center. Enlarging chondrocytes within calcifying matrix Epiphysis Diaphysis Marrow cavity Primary ossification center Bone formation Blood vessel Cartilage model Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -5 4 of 6

Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies. Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone. Blood vessels penetrate the cartilage. New osteoblasts form a primary ossification center. The bone of the shaft thickens, and the cartilage near each epiphysis is replaced by shafts of bone. Enlarging chondrocytes within calcifying matrix Epiphysis Diaphysis Marrow cavity Primary ossification center Bone formation Blood vessel Marrow cavity Blood vessel Cartilage model Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -5 5 of 6

Chondrocytes at the center of the growing cartilage model enlarge and then die as the matrix calicifies. Newly derived osteoblasts cover the shaft of the cartilage in a thin layer of bone. Blood vessels penetrate the cartilage. New osteoblasts form a primary ossification center. The bone of the shaft thickens, and the cartilage near each epiphysis is replaced by shafts of bone. Blood vessels invade the epiphyses and osteoblasts form secondary centers of ossification. Articular cartilage Enlarging chondrocytes within calcifying matrix Epiphysis Diaphysis Epiphyseal cartilage Marrow cavity Primary ossification center Bone formation Blood vessel Marrow cavity Blood vessel Secondary ossification center Cartilage model Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -5 6 of 6

Bone Formation and Growth Appositional Bone Growth Figure 6 -6

Bone Formation and Growth Requirements for Normal Bone Growth Minerals Calcium, phosphate Vitamins Vitamin D 3 Vitamin C Vitamin A Hormones Growth Hormone Sex hormones, thyroid hormone, others Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Remodeling/Homeostasis Role of Remodeling in Support Remodeling—Continuous breakdown and reforming of bone tissue Shapes reflect applied loads Mineral turnover enables adapting to new stresses Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Remodeling/Homeostasis What you don’t use, you lose. Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Remodeling/Homeostasis and Mineral Storage Bones store calcium Contain 99% of body calcium up to two kg calcium Hormones control storage/release PTH, calcitriol release bone calcium Calcitonin stores bone calcium Blood levels kept constant Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Bone Remodeling/Homeostasis Injury and Repair Fracture—A crack or break in a bone Steps in fracture repair Fracture hematoma Mitoses in periosteum, endosteum Internal callus External callus Bone remodeling Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops. Bone fragments An internal callus forms as a network of spongy bone unites the inner edges, and an external callus of cartilage and bone stabilizes the outer edges. Spongy bone Cartilage of internal of external callus The cartilage of the external callus has been replaced by bone, and struts of spongy bone now unite the broken ends. Fragments of dead bone and the areas of bone closest to the break have been removed and replaced. External callus Fracture hematoma Dead bone A swelling initially marks the location of the fracture. Over time, this region will be remodeled, and little evidence of the fracture will remain. New bone Periosteum Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Internal callus External callus Figure 6 -7 1 of 5

Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops. Bone fragments Fracture hematoma Dead bone Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -7 2 of 5

Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops. Bone fragments An internal callus forms as a network of spongy bone unites the inner edges, and an external callus of cartilage and bone stabilizes the outer edges. Spongy bone Cartilage of internal of external callus Fracture hematoma Dead bone New bone Periosteum Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -7 3 of 5

Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops. Bone fragments An internal callus forms as a network of spongy bone unites the inner edges, and an external callus of cartilage and bone stabilizes the outer edges. Spongy bone Cartilage of internal of external callus The cartilage of the external callus has been replaced by bone, and struts of spongy bone now unite the broken ends. Fragments of dead bone and the areas of bone closest to the break have been removed and replaced. Fracture hematoma Dead bone New bone Periosteum Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Internal callus External callus Figure 6 -7 4 of 5

Immediately after the fracture, extensive bleeding occurs. Over a period of several hours, a large blood clot, or fracture hematoma, develops. Bone fragments An internal callus forms as a network of spongy bone unites the inner edges, and an external callus of cartilage and bone stabilizes the outer edges. Spongy bone Cartilage of internal of external callus The cartilage of the external callus has been replaced by bone, and struts of spongy bone now unite the broken ends. Fragments of dead bone and the areas of bone closest to the break have been removed and replaced. External callus Fracture hematoma Dead bone PLAY A swelling initially marks the location of the fracture. Over time, this region will be remodeled, and little evidence of the fracture will remain. New bone Periosteum Internal callus Steps in the Repair of a Fracture Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings External callus Figure 6 -7 5 of 5

Aging and the Skeletal System Osteopenia—Less than normal ossification (mineral content) in bone Osteopenia starts before age 40 Women lose 8% per decade Men lose 3% per decade Spongy bone most affected Epiphyses Vertebrae Jaws Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

An Overview of the Skeleton Surface Features of Bones Table 6 -1 (2 of 2)

An Overview of the Skeleton Skeletal Divisions Axial skeleton Skull Thoracic cage and sternum Vertebral column Appendicular skeleton Upper, lower limbs Pectoral girdle Pelvic girdle Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

An Overview of the Skeleton The Skeleton Figure 6 -8(a)

An Overview of the Skeleton The Skeleton Figure 6 -8(b)

An Overview of the Skeleton The Axial and Appendicular Divisions of the Skeleton. Figure 6 -9

The Axial Division: The Skull Bones of the Cranium Frontal bone Forehead, Parietal Sides, bones roof Occipital bone Foramen Temporal Sides, superior surface of orbits magnum bones base Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Axial Division: The Skull Bones of the Cranium (continued) Sphenoid Bridge bone between cranial and facial bones Ethmoid bone Cribriform plate Nasal septum Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Axial Division: The Skull The Adult Skull (Part I) Figure 6 -10

The Axial Division: The Skull Bones of the Face Maxillary bones Zygomatic arch (with temporal bones) Mandible Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Axial Division: The Skull Bones of the Face (continued) Palatine bones The Vomer Nasal bones Lacrimal bones Inferior nasal conchae Nasal complex Nasal septum Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Axial Division: The Skull Bones of the Face (continued) Paranasal sinuses Frontal Sphenoidal Ethmoidal Palatine Maxillary Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

The Axial Division: The Skull The Adult Skull (Part II) Figure 6 -11(a)

The Axial Division: The Skull The Adult Skull (Part II) Figure 6 -11(b)

The Axial Division: The Skull Sectional Anatomy of the Skull Figure 6 -12(a)

The Axial Division: The Skull Sectional Anatomy of the Skull Figure 6 -12(b)

The Axial Division: The Skull Sectional Anatomy of the Skull Figure 6 -12(c)

The Axial Division: The Skull The Paranasal Sinuses Figure 6 -13

Axial Division: The Skull of a Newborn Figure 6 -15(a)

Axial Division: The Skull of a Newborn Figure 6 -15(b)

Cleft Lip Unilateral incomplete Unilateral complete Bilateral Complete

Cleft Lip

Prevalence of cleft lip Native Americans: 3. 74/1000 Japanese: 0. 82/1000 to 3. 36/1000 Chinese: 1. 45/1000 to 4. 04/1000 Caucasians: 1. 43/1000 to 1. 86/1000 Latin Americans: 1. 04/1000 Africans: 0. 18/1000 to 1. 67/1000

Cleft Palate Incomplete cleft palate Complete unilateral lip & palate cleft Complete bilateral lip & palate cleft

Vertebral Column/Thoracic Cage Vertebral Column (Spine) 26 7 Bones Cervical vertebrae (C 1 to C 7) 12 Thoracic vertebrae (T 1 to T 12) 5 Lumbar vertebrae (L 1 to L 5) Sacrum Coccyx (tailbone) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Vertebral Column/Thoracic Cage Spinal Curvature Alignment of body weight Primary curves Thoracic Sacral Secondary curves Cervical Lumbar Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Vertebral Column/Thoracic Cage The Vertebral Column Figure 6 -16

Vertebral Column/Thoracic Cage Vertebral Anatomy Body Arch Transverse, spinous processes Pedicle, lamina Vertebral foramen Vertebral canal Articular processes Articular facets Intervertebral discs Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Vertebral Column/Thoracic Cage Regional Differences in Vertebrae Cervical Oval body Transverse foramina Thoracic Heart-shaped body Lumbar Massive (heaviest loading) Blade-like transverse processes Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Vertebral Column/Thoracic Cage Typical Vertebrae of the Cervical, Thoracic, and Lumbar Regions Figure 6 -17(a)

Vertebral Column/Thoracic Cage Typical Vertebrae of the Cervical, Thoracic, and Lumbar Regions Figure 6 -17(b)

Vertebral Column/Thoracic Cage Typical Vertebrae of the Cervical, Thoracic, and Lumbar Regions Figure 6 -17(c)

Vertebral Column/Thoracic Cage The Atlas and Axis Figure 6 -18

Vertebral Column/Thoracic Cage Functions of Sacrum Protects pelvic organs Base articulates with lumbar vertebra Apex articulates with coccyx Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Vertebral Column/Thoracic Cage The Sacrum and Coccyx Figure 6 -19(a)

Vertebral Column/Thoracic Cage The Sacrum and Coccyx Figure 6 -19(b)

Vertebral Column/Thoracic Cage Components of Thoracic Cage Thoracic vertebrae Ribs Seven pairs of true ribs Cartilaginous joint with sternum Five pairs of false ribs Sternum Manubrium, body, xiphoid process Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Vertebral Column/Thoracic Cage The Thoracic Cage Figure 6 -20(a)

Vertebral Column/Thoracic Cage The Thoracic Cage Figure 6 -20(b)

Appendicular Division Pectoral Girdle (Shoulder Girdle) Components Scapulae (“shoulder blade”) Coracoid process Acromium Scapular spine Clavicles (“collar bone”) Functions Shoulder, arm movement Articulation for arm Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division The Clavicle Figure 6 -21

Appendicular Division The Scapula Figure 6 -22

Tuberosity Large, roughened elevation on a bony surface Condyle Rounded articular projection on the surface of a bone Trochlea A pulley Fossa Shallow depression in surface of bone Foramen Opening Sinus or passage through a bone

Appendicular Division Upper Limb Humerus Head articulates with scapula Muscles attach to Greater, lesser tubercles Deltoid tuberosity Medial, lateral epicondyles Distal condyle articulates with forearm Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division Upper Limb Anatomy Distal articulation of humerus Coronoid fossa Olecranon fossa Trochlea Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division The Humerus Figure 6 -23

Appendicular Division Bones of the Forearm Radius Lateral (thumb side) Head articulates with humerus Radial tuberosity attaches biceps brachii Participates in wrist joint Ulna Trochlear notch articulates with humerus Olecranon forms point of elbow Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division The Radius and Ulna Figure 6 -24

Appendicular Division Bones of the Wrist and Hand Two rows of carpal bones Proximal Distal articulation with radius articulation with metacarpal bones Proximal phalanges (finger bones) articulate with metacarpals Three Two phalanges/finger phalanges/thumb (pollex) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division Bones of the Wrist and Hand Figure 6 -25

Appendicular Division The Pelvic Girdle Formed by two hipbones formed by fusion of: Ilium Ischium Pubis Pubic Pelvis symphysis limit movement formed by coxae, sacrum, coccyx Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division The Pelvis Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -26(a)

Appendicular Division The Pelvis Figure 6 -26(b)

Appendicular Division The Pelvis Figure 6 -26(c)

Appendicular Division Differences in the Anatomy of the Pelvis in Males and Females Figure 6 -27

Appendicular Division Bones of the Lower Limb Femur (thighbone) Patella (kneecap) Tibia (shinbone) Fibula Ankle bones Foot bones Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division The Femur Figure 6 -28

Appendicular Division Bones of the Lower Limb Features Tibial of the tibia tuberosity Patellar tendon attachment Anterior crest Medial malleolus Features of the fibula Articulation of head with tibia Lateral malleolus Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division The Right Tibia and Fibula Figure 6 -29

Appendicular Division The Bones of the Ankle and Foot Ankle Seven tarsal bones Talus Joint with tibia, fibula Foot Calcaneus (heel bone) Major load-bearing bone Metatarsal bones Five phalanges (toes) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Appendicular Division The Bones of the Ankle and Foot Figure 6 -30(a)

Appendicular Division The Bones of the Ankle and Foot Figure 6 -30(b)

Articulations Classification of Joints (Articulations) Joint—Where two bones interact Three functional classes of joint Synarthroses Immovable Amphiarthroses Slightly movable Diarthroses Freely movable Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations Examples of Joints Synarthroses Suture Gomphosis Synchondrosis Amphiarthroses Syndesmosis Symphysis Diarthroses Synovial joints Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations Synovial Joints (Diarthroses) Epiphyses covered by articular cartilage Lubricated by synovial fluid Enclosed within joint capsule Other synovial structures include: Menisci Bursae Fat pads Ligaments Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations The Structure of Synovial Joints Figure 6 -31(a)

Articulations The Structure of Synovial Joints Figure 6 -31(b)

Articulations Synovial Joints: Movements Flexion Extension Hyperextension Abduction Adduction Circumduction Rotation Supination Pronation Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations Angular Movements Figure 6 -32(a)

Articulations Angular Movements Figure 6 -32(b)

Articulations Angular Movements Figure 6 -32(c)

Articulations Angular Movements Figure 6 -32(d)

Articulations Rotational Movements Figure 6 -33(a)

Articulations Rotational Movements Figure 6 -33(b)

Articulations Special Movements Foot and ankle Inversion, eversion Dorsiflexion, plantar flexion Hand Opposition of thumb, palm Head Protraction, retraction Depression, elevation (jaw) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations Special Movements Figure 6 -34

Articulations Structural Classification of Synovial Joints Gliding (e. g. , vertebra–vertebra) Hinge (e. g. , knee) Pivot (e. g. , atlas–axis) Ellipsoidal (e. g. , distal radius) Saddle (e. g. , thumb) Ball-and-Socket (e. g. , hip) Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations Structural Classification of Synovial Joints Figure 6 -35(a)

Articulations Structural Classification of Synovial Joints Figure 6 -35(b)

Articulations Structural Classification of Synovial Joints Figure 6 -35(c)

Articulations Figure 6 -35(d)

Articulations Structural Classification of Synovial Joints Figure 6 -35(e)

Articulations Structural Classification of Synovial Joints Figure 6 -35(f)

Articulations Greater mobility = weaker joint Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations Intervertebral Articulations Two kinds join adjacent vertebrae Gliding joints Between superior and inferior articular processes Permit small movements Symphyseal joints Intervertebral discs composed of fibrocartilage Cushion and connect Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations The Shoulder Joint Ball-and-socket design frees movement Joint dislocates easily Bursae reduce friction Bursitis restricts motion, causes pain Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations The Shoulder Joint Figure 6 -37

Articulations The Elbow Joint Two articulations Humerus–radius Humerus–ulna Interlocking hinge design Limited movement Flexion and extension only Strong ligaments Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations The Elbow Joint Figure 6 -38

Articulations The Hip Joint Extremely strong, stable joint Many strong ligaments Tough joint capsule Bulky muscles Versatile movements Flexion, extension, adduction, abduction, circumduction, rotation Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations The Hip Joint Figure 6 -39

Articulations The Knee Joint Complex Three hinge joint separate articulations Femur-tibia (between condyles—lateral and medial) Femur-patella Fibrocartilage pads Ligaments Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings

Articulations The Knee Joint Figure 6 -40

The Skeletal System in Perspective Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 1 of 11

The Integumentary System • • Synthesizes vitamin D 3, essential for calcium and phosphorus absorption (bone maintenance and growth) Provides structural support Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 2 of 11

The Muscular System • • Stabilizes bone positions; tension in tendons stimulates bone growth and maintenance Provides calcium needed for normal muscle contraction; bones act as levers to produce body movements Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 3 of 11

The Nervous System • • Regulates bone position by controlling muscle contractions Provides calcium for neural function; protects brain, spinal cord; receptors at joints provide information about body position Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 4 of 11

The Endocrine System • • Skeletal growth regulated by growth hormone, thyroid hormones, and sex hormones; calcium mobilization regulated by parathyroid hormone and calcitonin Protects endocrine organs, especially in brain, chest, and pelvic cavity Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 5 of 11

The Cardiovascular System • • Provides oxygen, nutrients, hormones, blood cells; removes waste products and carbon dioxide Provides calcium needed for cardiac muscle contraction, blood cells produced in bone marrow Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 6 of 11

The Lymphatic System • • Lymphocytes assist in the defense and repair of bone following injuries Lymphocytes and other cells of the immune response are produced and stored in bone marrow Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 7 of 11

The Respiratory System • • Provides oxygen and eliminates carbon dioxide Movements of ribs important in breathing; axial skeleton surrounds and protects lungs Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 8 of 11

The Digestive System • • Provides nutrients, calcium, and phosphate Ribs protect portions of liver, stomach, and intestines Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 9 of 11

The Urinary System • • Conserves calcium and phosphate needed for bone growth; disposes of waste products Axial skeleton provides some protection for kidneys and ureters; pelvis protects urinary bladder and proximal urethra Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 10 of 11

The Reproductive System • • Sex hormones stimulate growth and maintenance of bones; surge of sex hormones at puberty causes acceleration of growth and closure of epiphyseal cartilages Pelvis protects reproductive organs of female, protects portion of ductus deferens and accessory glands in males Copyright © 2007 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 6 -41 11 of 11