CHAPTER 6: THE SKELETAL SYSTEM. Copyright 2010 Pearson Education, Inc.

Transcription

1 CHAPTER 6: THE SKELETAL SYSTEM

2 SKELETAL CARTILAGE

3 Figure 6.1 The bones and cartilages of the human skeleton. Cartilage in Intervertebral disc Cartilage in external ear Cartilages in nose Articular Cartilage of a joint Costal cartilage Epiglottis Thyroid cartilage Cricoid cartilage Larynx Trachea Lung Respiratory tube cartilages in neck and thorax Pubic symphysis Meniscus (padlike cartilage in knee Articular joint) cartilage of a joint Bones of skeleton Axial skeleton Appendicular skeleton Cartilages Hyaline cartilages Elastic cartilages Fibrocartilages

4 GROWTH OF CARTILAGE

5 Intervertebral discs are made of which type of cartilage? 1) Elastic cartilage 2) Fibrocartilage 3) Hyaline cartilage

6 BONE CLASSIFICATION

7 AXIAL VS. APPENDICULAR

8 Figure 6.1 The bones and cartilages of the human skeleton. Cartilage in Intervertebral disc Cartilage in external ear Cartilages in nose Articular Cartilage of a joint Costal cartilage Epiglottis Thyroid cartilage Cricoid cartilage Larynx Trachea Lung Respiratory tube cartilages in neck and thorax Pubic symphysis Meniscus (padlike cartilage in knee Articular joint) cartilage of a joint Bones of skeleton Axial skeleton Appendicular skeleton Cartilages Hyaline cartilages Elastic cartilages Fibrocartilages

9 Figure 6.2 Classification of bones on the basis of shape. (a) Long bone (humerus) (c) Flat bone (sternum) (b) Irregular bone (vertebra), right lateral view (d) Short bone (talus)

10 FUNCTIONS OF BONES

11 True or false: Every bone has the same primary functions. 1) True 2) False

12 BONE STRUCTURE GROSS STRUCTURE

13 Figure 6.3 The structure of a long bone (humerus of arm). Articular cartilage Proximal epiphysis Spongy bone Epiphyseal line Periosteum Compact bone Endosteum Compact bone Diaphysis Medullary cavity (lined by endosteum) (b) Yellow bone marrow Compact bone Periosteum Perforating (Sharpey s) fibers Distal epiphysis (a) Nutrient arteries (c)

14 Figure 6.5 Flat bones consist of a layer of spongy bone sandwiched between two thin layers of compact bone. Spongy bone (diploë) Compact bone Trabeculae

15 The connective tissue surrounding a bone is called the 1) Diaphysis 2) Endosteum 3) Epiphysium 4) Periosteum

16 True or false: Trabeculae are found in compact bone. 1) True 2) False

17 BONE STRUCTURE MICROSCOPIC ANATOMY

18 Figure 6.4 Comparison of different types of bone cells. (a) Osteogenic cell (b) Osteoblast (c) Osteocyte Stem cell Matrix-synthesizing cell responsible for bone growth Mature bone cell that maintains the bone matrix (d) Osteoclast Bone-resorbing cell

19 Figure 6.6 A single osteon. Structures in the central canal Artery with capillaries Vein Nerve fiber Lamellae Collagen fibers run in different directions Twisting force

20 Figure 6.7 Microscopic anatomy of compact bone. Compact bone Spongy bone Central (Haversian) canal Osteon (Haversian system) Circumferential lamellae Perforating (Volkmann s) canal Endosteum lining bony canals and covering trabeculae (a) Lamellae Perforating (Sharpey s) fibers Periosteal blood vessel Periosteum Nerve Vein Artery Canaliculi Osteocyte in a lacuna (b) Lamellae Central canal Lacunae (c) Interstitial lamellae Lacuna (with osteocyte)

21 The cells which build new bone are: 1) Osteoblasts 2) Osteogenic cells 3) Osteoclasts 4) Osteocytes

22 Osteocytes receive their nutrition from fluid in the, which are connected to the larger. 1) Canaliculi / central canal 2) Lamellae / lacunae 3) Osteoblasts / lacunae

23 BONE STRUCTURE CHEMICAL COMPOSITION OF BONE

24 Hydroxyapatite is part of the component of bone. 1) Cellular 2) Organic 3) Inorganic

25 OSTEOGENESIS INTRAMEMBRANOUS OSSIFICATION

26 Figure 6.8 Intramembranous ossification. Mesenchymal cell Collagen fiber Ossification center Osteoid Osteoblast Mesenchyme condensing to form the periosteum Trabeculae of woven bone Blood vessel Osteoblast Osteoid Osteocyte Newly calcified bone matrix 1 Ossification centers appear in the fibrous 2 Bone matrix (osteoid) is secreted within the connective tissue membrane. fibrous membrane and calcifies. Selected centrally located mesenchymal cells cluster Osteoblasts begin to secrete osteoid, which is calcified and differentiate into osteoblasts, forming an within a few days. ossification center. Trapped osteoblasts become osteocytes. Fibrous periosteum Osteoblast Plate of compact bone Diploë (spongy bone) cavities contain red marrow 3 Woven bone and periosteum form. 4 Lamellar bone replaces woven bone, just deep to Accumulating osteoid is laid down between embryonic the periosteum. Red marrow appears. blood vessels in a random manner. The result is a network Trabeculae just deep to the periosteum thicken, and are later (instead of lamellae) of trabeculae called woven bone. replaced with mature lamellar bone, forming compact bone Vascularized mesenchyme condenses on the external face plates. of the woven bone and becomes the periosteum. Spongy bone (diploë), consisting of distinct trabeculae, persists internally and its vascular tissue becomes red marrow.

27 OSTEOGENESIS ENDOCHONDRIAL OSSIFICATION

28 Figure 6.9 Endochondral ossification in a long bone. Week 9 Month 3 Birth Secondary ossification center Articular cartilage Spongy bone Childhood to adolescence Hyaline cartilage Area of deteriorating cartilage matrix Spongy bone formation Epiphyseal blood vessel Medullary cavity Epiphyseal plate cartilage Bone collar Primary ossification center Blood vessel of periosteal bud 1 Bone collar 2 Cartilage in the 3 The periosteal 4 5 forms around hyaline cartilage model. center of the diaphysis calcifies and then develops cavities. bud invades the internal cavities and spongy bone begins to form. The diaphysis elongates and a medullary cavity forms as ossification continues. Secondary ossification centers appear in the epiphyses in preparation for stage 5. The epiphyses ossify. When completed, hyaline cartilage remains only in the epiphyseal plates and articular cartilages.

29 The starting point for endochondrial ossification is called the 1) Medullary cavity 2) Periosteal bud 3) Primary ossification center 4) Bone collar

30 POSTNATAL BONE GROWTH AND REMODELING

31 Figure 6.10 Growth in length of a long bone occurs at the epiphyseal plate. Resting zone 1 Proliferation zone Cartilage cells undergo mitosis. Calcified cartilage spicule Osteoblast depositing bone matrix Osseous tissue (bone) covering cartilage spicules 2 Hypertrophic zone Older cartilage cells enlarge. 3 Calcification zone Matrix becomes calcified; cartilage cells die; matrix begins deteriorating. 4 Ossification zone New bone formation is occurring.

32 Figure 6.11 Long bone growth and remodeling during youth. Bone growth Bone remodeling Cartilage grows here. Cartilage is replaced by bone here. Cartilage grows here. Cartilage is replaced by bone here. Articular cartilage Epiphyseal plate Bone is resorbed here. Bone is added by appositional growth here. Bone is resorbed here.

33 Growth of bone length is due largely to increasing numbers of cells in the zone 1) calcification 2) hypertrophic 3) ossification 4) proliferation

34 CONTROL OF BONE REMODELING

35 Figure 6.12 Parathyroid hormone (PTH) control of blood calcium levels. Calcium homeostasis of blood: 9 11 mg/100 ml BALANCE BALANCE Stimulus Falling blood Ca 2+ levels Thyroid gland Osteoclasts degrade bone matrix and release Ca 2+ into blood. Parathyroid glands PTH Parathyroid glands release parathyroid hormone (PTH).

36 Figure 6.13 Bone anatomy and bending stress. Load here (body weight) Head of femur Tension here Compression here Point of no stress

37 Which of the following does NOT control bone growth or remodeling? 1) Growth hormone 2) Mechanical force 3) Parathyroid hormone 4) Thyroid hormone 5) Calcitonin

38 FRACTURES

39 Table 6.2 Common Types of Fractures (1 of 3)

40 Table 6.2 Common Types of Fractures (2 of 3)

41 Table 6.2 Common Types of Fractures (3 of 3)

42 The type of fracture which commonly occurs in porous bones subjected to a fall is a 1) Comminuted fracture 2) Compression fracture 3) Spiral fracture 4) Epiphyseal fracture 5) Depression fracture 6) Greenstick fracture

43 BONE REPAIR

44 Figure 6.15 Stages in the healing of a bone fracture. Hematoma Internal callus (fibrous tissue and cartilage) 1 A hematoma forms. 2 Fibrocartilaginous callus forms. External callus New blood vessels Spongy bone trabecula Bony callus of spongy bone Healed fracture 3 Bony callus forms. 4 Bone remodeling occurs.

45 True or false: if a bone breaks, it bleeds. 1) True 2) False

46 HOMEOSTATIC IMBALANCES

47 Figure 6.16 The contrasting architecture of normal versus osteporotic bone.

48 The disease which causes children to have soft, malformed bones due to vitamin D or calcium deficiency is 1) Rickets 2) Osteomalacia 3) Osteporosis 4) Paget s Disease

49 FETAL SKELETAL DEVELOPMENT

50 Figure 6.17 Fetal primary ossification centers at 12 weeks. Parietal bone Occipital bone Mandible Clavicle Scapula Ribs Frontal bone of skull Radius Ulna Humerus Vertebra Ilium Femur Tibia