1. Structure and Function of the Musculoskeletal System Chapter 41 Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.

2. 2 Skeletal System Forms the body Forms the body Supports tissues Supports tissues Permits movement by providing points of attachment for muscles Permits movement by providing points of attachment for muscles Site of blood cell formation Site of blood cell formation Mineral storage Mineral storage

3. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 3 Bone Rigid yet flexible connective tissue Rigid yet flexible connective tissue Constituents Constituents Cells Cells Fibers Fibers Ground substance Ground substance

4. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 4 Bone Tissue Osteoblasts Osteoblasts Derived from mesenchymal cells Derived from mesenchymal cells Produce type I collagen Produce type I collagen Respond to parathyroid hormone Respond to parathyroid hormone Produce osteocalcin Produce osteocalcin Synthesize osteoid Synthesize osteoid Nonmineralized bone matrix Nonmineralized bone matrix

5. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 5 Bone Tissue Osteocyte Osteocyte Transformed osteoblast surrounded in osteoid as it hardens from deposited minerals Transformed osteoblast surrounded in osteoid as it hardens from deposited minerals Osteoclast Osteoclast The major reabsorptive cell of the bone The major reabsorptive cell of the bone Large, multinucleated cells Large, multinucleated cells Contains lysosomes filled with hydrolytic enzymes Contains lysosomes filled with hydrolytic enzymes

6. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 6 Bone Matrix 35% organic and 65% inorganic 35% organic and 65% inorganic Collagen fibers Collagen fibers Calcium and phosphate minerals Calcium and phosphate minerals Proteoglycans Proteoglycans Glycoproteins Glycoproteins

7. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 7 Bone Tissue Compact (cortical) bone Compact (cortical) bone 85% of the skeleton 85% of the skeleton Haversian system Haversian system Haversian canal, lamellae, lucunae, osteocyte, and canaliculi Haversian canal, lamellae, lucunae, osteocyte, and canaliculi Spongy (cancellous) bone Spongy (cancellous) bone Lack haversian systems Lack haversian systems Trabeculae Trabeculae Periosteum Periosteum

8. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 8 Compact Bone

9. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 9 Bone 206 bones 206 bones Axial skeleton Axial skeleton 80 bones 80 bones Skull, vertebral column, thorax Skull, vertebral column, thorax Appendicular skeleton Appendicular skeleton 126 bones 126 bones Upper and lower extremities, the shoulder girdle, the pelvic girdle Upper and lower extremities, the shoulder girdle, the pelvic girdle

10. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 10 Skeleton

11. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 11Bones Long bones Long bones Diaphysis Diaphysis Metaphysis Metaphysis Epiphysis Epiphysis Epiphyseal plate Epiphyseal plate In a child epiphysis is separated from metaphysis by a cartilaginous growth plate. After puberty epiphyseal plate calcifies and epiphysis and metaphysis merge In a child epiphysis is separated from metaphysis by a cartilaginous growth plate. After puberty epiphyseal plate calcifies and epiphysis and metaphysis merge Epiphyseal line Epiphyseal line Medullary cavity Medullary cavity Endosteum Endosteum

12. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 12 Long Bone

13. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 13 Bones Flat bones Flat bones Short bones (cuboidal bones) Short bones (cuboidal bones) Irregular bones Irregular bones

14. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 14 Bone Remodeling Bone-remodeling units Bone-remodeling units Repairs microscopic injuries and maintains bone integrity Repairs microscopic injuries and maintains bone integrity Phases Phases Activation of the remodeling cycle Activation of the remodeling cycle Reabsorption Reabsorption Formation of new bone Formation of new bone

15. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 15 Bone Remodeling

16. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 16 Bone Wound Healing Hematoma formation Hematoma formation Procallus formation Procallus formation Callus formation Callus formation Callus replacement Callus replacement Remodeling Remodeling

17. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 17 Joints Site where two or more bones meet Site where two or more bones meet Promote stability and mobility of the skeleton Promote stability and mobility of the skeleton

18. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 18 Joints Joint classifications based on movement Joint classifications based on movement Synarthrosis Synarthrosis Immovable Immovable Amphiarthrosis Amphiarthrosis Slightly movable Slightly movable Diarthrosis Diarthrosis Freely movable Freely movable

19. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 19 Joints Joint classifications based on structure Joint classifications based on structure Fibrous Fibrous Usually synarthroses (immovable) Usually synarthroses (immovable) However, many allow some movement However, many allow some movement Degree of movement depends on the distance between the bones and the flexibility of the fibrous connective tissue Degree of movement depends on the distance between the bones and the flexibility of the fibrous connective tissue Sutures, syndesmoses, and gomphoses Sutures, syndesmoses, and gomphoses

20. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 20 Joints Joint classifications based on structure Joint classifications based on structure Cartilaginous Cartilaginous Symphysis Symphysis Bones are united by a pad or disk of fibrocartilage Bones are united by a pad or disk of fibrocartilage Example: symphysis pubis, intervetebral disks Example: symphysis pubis, intervetebral disks Synchondrosis Synchondrosis Bones are united by hyaline cartilage Bones are united by hyaline cartilage Example: joints between the ribs and the sternum Example: joints between the ribs and the sternum

21. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 21 Joints Classifications based on structure Classifications based on structure Synovial (most movable, most complex) contain: Synovial (most movable, most complex) contain: A fibrous joint capsule (articular capsule) A fibrous joint capsule (articular capsule) Synovial membrane that lines inner surface of joint capsule Synovial membrane that lines inner surface of joint capsule Joint cavity (synovial cavity), a space formed by the capsule Joint cavity (synovial cavity), a space formed by the capsule Synovial fluid, which fills the joint cavity and lubricates joint surface Synovial fluid, which fills the joint cavity and lubricates joint surface Articular cartilage, which covers and pads the articulating bony surfaces Articular cartilage, which covers and pads the articulating bony surfaces

22. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 22 Joints

23. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 23 Joints

24. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 24 Joints

25. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 25 Joints

26. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 26 Joints

27. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 27 Skeletal Muscles Millions of individual muscle fibers that contract and relax to facilitate movement Millions of individual muscle fibers that contract and relax to facilitate movement 75% water, 20% protein, 5% organic and inorganic compounds 75% water, 20% protein, 5% organic and inorganic compounds 350 named muscles (most are paired) 350 named muscles (most are paired) 2 to 60 cm long 2 to 60 cm long Fusiform muscles Fusiform muscles Pennate muscles Pennate muscles

28. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 28 Skeletal Muscles

29. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 29 Skeletal Muscles Whole muscle Whole muscle Fascia Fascia Epimysium Epimysium Tendon Tendon Perimysium Perimysium Fascicles Fascicles Endomysium Endomysium

30. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 30 Muscle Skeletal muscle Skeletal muscle Voluntary Voluntary Controlled directly by the central nervous system Controlled directly by the central nervous system Striated Striated The striated, or striped, pattern of skeletal muscle The striated, or striped, pattern of skeletal muscle Result from organization of muscle fibers into the contractile units called sarcomeres Result from organization of muscle fibers into the contractile units called sarcomeres Extrafusal Extrafusal Distinguishes skeletal muscle fibers from other contractile fibers Distinguishes skeletal muscle fibers from other contractile fibers

31. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 31 Muscle Motor unit (anterior horn cell, its axon, and its muscle fiber) Motor unit (anterior horn cell, its axon, and its muscle fiber) Anterior horn cell of the spinal cord Anterior horn cell of the spinal cord Axons of motor nerves branch out to innervate a specific group of muscle fibers; lower motor neurons Axons of motor nerves branch out to innervate a specific group of muscle fibers; lower motor neurons Functional unit of the neuromuscular system Functional unit of the neuromuscular system Innervation ratio Innervation ratio Sensory receptors Sensory receptors

32. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 32 Motor Units

33. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 33 Muscle Innervation ratio Innervation ratio Motor units per muscle Motor units per muscle The greater the innervation ratio of a particular organ, the greater its endurance The greater the innervation ratio of a particular organ, the greater its endurance Higher innervation ratios prevent fatigue Higher innervation ratios prevent fatigue Lower innervation ratios allow for precision of movement Lower innervation ratios allow for precision of movement

34. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 34Muscle Sensory receptors (send signals to the central nervous system) Sensory receptors (send signals to the central nervous system) Spindles Spindles Mechanoreceptors that lie parallel to muscle fibers Mechanoreceptors that lie parallel to muscle fibers Respond to muscle stretching Respond to muscle stretching Golgi tendon organs: dendrites that terminate and branch to tendons near the neuromuscular junction Golgi tendon organs: dendrites that terminate and branch to tendons near the neuromuscular junction Spindles, Golgi tendon organs, and free nerve endings report changes in muscle length, tension, velocity Spindles, Golgi tendon organs, and free nerve endings report changes in muscle length, tension, velocity System of afferent signals responsible for muscle stretch response and maintaining muscle tone System of afferent signals responsible for muscle stretch response and maintaining muscle tone

35. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 35 Muscle Fibers Myofibrils Myofibrils Myoblasts Myoblasts White muscle (type II fibers) White muscle (type II fibers) Red muscle (type I fibers) Red muscle (type I fibers) Muscle membrane Muscle membrane Sarcolemma and basement membrane Sarcolemma and basement membrane Sarcoplasm Sarcoplasm

36. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 36 Muscle Fibers Sarcotubular system Sarcotubular system Transverse tubules Transverse tubules Sarcoplasmic reticulum Sarcoplasmic reticulum Sarcomere Sarcomere Actin Actin Myosin Myosin Troponin-tropomyosin complex Troponin-tropomyosin complex

37. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 37 Myofibrils

38. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 38 Myofibrils

39. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 39 Muscle Fibers Creatine and creatine kinase Creatine and creatine kinase Phosphate, chloride, calcium, magnesium, sodium, potassium Phosphate, chloride, calcium, magnesium, sodium, potassium

40. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 40 Muscle Contraction Activation Activation Muscle fiber action potential Muscle fiber action potential Coupling Coupling Contraction Contraction Cross-bridge theory Cross-bridge theory Relaxation Relaxation

41. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 41 Muscle Contractions and Movement Types of contractions Types of contractions Isometric Isometric Isotonic Isotonic Eccentric Eccentric Concentric Concentric Muscle movement Muscle movement Agonist Agonist Antagonist Antagonist

42. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 42 Test of Bone Function Gait analysis Gait analysis Serum calcium and phosphorus Serum calcium and phosphorus X-rays X-rays Angiography Angiography Bone scanning Bone scanning

43. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 43 Test of Joint Function Arthrography Arthrography Arthroscopy Arthroscopy MRI MRI Synovial fluid analysis Synovial fluid analysis

44. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 44 Test of Muscular Function Serum creatine kinase Serum creatine kinase Myoglobin Myoglobin EMG EMG

45. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 45 Aging and the Musculoskeletal System Bones Bones Bone loss Bone loss Stiff, brittle, decreased strength Stiff, brittle, decreased strength Bone remodel time is lengthened Bone remodel time is lengthened Joints Joints Cartilage becomes more rigid, fragile, stiff Cartilage becomes more rigid, fragile, stiff Decreased range of motion Decreased range of motion

46. Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc. 46 Aging and the Musculoskeletal System Muscles Muscles Sarcopenia Sarcopenia Decrease in muscle strength and bulk Decrease in muscle strength and bulk Reduced oxygen intake, basal metabolic rate, and lean body mass Reduced oxygen intake, basal metabolic rate, and lean body mass