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Chapter 6

컨트롤 버튼이 '내비게이션' 모드로 변경되었습니다.
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  • Major functions of the skeletal system

    The skeletal system provides support, protection, movement, mineral storage, blood cell production, and energy storage.

  • Classification of bones by shape

    Bone shapes include sutural, irregular, short, flat, long, and sesamoid bones.

  • Sutural bones

    Small, flat, irregularly shaped bones found between flat bones of the skull; borders fit like a jigsaw puzzle.

  • Flat bones

    Thin, parallel surfaces; provide protection and large surface area for muscle attachment; examples include skull roof, sternum, ribs, scapulae.

  • Irregular bones

    Complex shapes with ridges or notches; examples include vertebrae, pelvic bones, and some skull bones.

  • Long bones

    Relatively long and slender; found in arms, legs, palms, soles, fingers, and toes; femur is the largest and heaviest.

  • Short bones

    Boxlike in appearance; examples include carpal (wrist) and tarsal (ankle) bones.

  • Sesamoid bones

    Small, round, flat bones developing within tendons near joints; patellae (kneecaps) are universal sesamoid bones.

  • Bone markings: projections and openings

    Projections serve as attachment points for muscles and ligaments or form joints; openings allow passage of blood vessels and nerves.

  • Examples of bone projections

    Trochanter, crest, spine, head, neck, line, tubercle, tuberosity, facet, condyle, and trochlea.

  • Examples of bone openings and depressions

    Sinus, foramen, fissure, meatus, canal, sulcus, and fossa.

  • Structure of a long bone

    Consists of a diaphysis (shaft) of compact bone surrounding a medullary cavity, and epiphyses (ends) mostly of spongy bone; metaphysis is the region between.

  • Structure of flat bones

    Consist of spongy bone (diploë) sandwiched between two layers of compact bone (cortex).

  • Bone tissue characteristics

    Dense connective tissue with a solid extracellular matrix of collagen fibers and calcium salts; contains osteocytes in lacunae connected by canaliculi.

  • Types of bone cells and functions

    Osteogenic cells (stem cells), osteoblasts (build bone matrix), osteocytes (maintain matrix), osteoclasts (resorb bone matrix).

  • Compact bone structure

    Organized into osteons with central canals containing blood vessels; lamellae are concentric layers of matrix; perforating canals connect osteons.

  • Spongy bone structure

    Lacks osteons; composed of trabeculae forming an open network; spaces filled with red or yellow bone marrow.

  • Periosteum and endosteum

    Periosteum covers outer bone surfaces with fibrous and cellular layers; endosteum lines medullary cavity and trabeculae, active in growth and repair.

  • Endochondral ossification

    Bone forms by replacing hyaline cartilage; primary ossification center forms in diaphysis, secondary centers in epiphyses; epiphyseal plate allows growth in length.

  • Intramembranous ossification

    Bone develops directly from mesenchymal tissue; forms dermal bones like mandible and clavicles; involves ossification centers and spicule formation.

  • Bone remodeling

    Continuous process involving osteoclasts resorbing bone and osteoblasts forming new bone; maintains bone strength and mineral homeostasis.

  • Effects of exercise on bone

    Weight-bearing exercise stimulates osteoblasts, increasing bone density and strength; inactivity leads to rapid bone loss.

  • Nutritional and hormonal effects on bone

    Calcium, phosphorus, vitamins D, C, A, K, B12, and hormones like growth hormone, thyroxine, estrogen, testosterone, parathyroid hormone, and calcitonin regulate bone growth and maintenance.

  • Calcium homeostasis and hormones

    Parathyroid hormone increases blood calcium by stimulating osteoclasts and reducing excretion; calcitonin lowers blood calcium by inhibiting osteoclasts and increasing excretion.

  • Types of bone fractures

    Include transverse, displaced, compression, spiral, epiphyseal, comminuted, greenstick, Colles, and Pott’s fractures.

  • Steps in fracture repair

    Fracture hematoma formation, callus formation (internal and external), spongy bone formation, and compact bone formation.

  • Effects of aging on the skeletal system

    Bone mass decreases (osteopenia), increasing fragility; osteoporosis is severe bone loss, especially in postmenopausal women; cancer can accelerate bone loss.